Application Finder

Corrosion of metals is a problem seriously affecting not only many industrial sectors, but also private life, resulting in enormous costs. In this application note, the results gained during electrochemical corrosion studies on different metals are compared to literature data.

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of mercury in metallic materials can be carried out by anodic stripping voltammetry (ASV) at a gold rotating disk electrode (Au-RDE).

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of lead and cadmium in metallic materials can be carried out by anodic stripping voltammetry (ASV) using ammonium oxalate buffer pH 2.

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of chromium(VI) in chromate coating on metallic materials can be carried out by adsorptive stripping voltammetry (AdSV) using DTPA (diethylenetriamine pentaacetic acid) as complexing agent.

This Application Note presents DPV as a sensitive, selective method for detecting heavy metals in water, detailing setup, parameters, and advantages over other techniques.

The metals Cd, Co, Cu, Fe, Ni, Pb, and Zn are determined in the sub-ppb range (limit of detection 0.05 µg/L) by means of stripping voltammetry. The DP-ASV method is used for Cd, Cu, Pb, and Zn whereas Co, Ni, and Fe are determined by means of the DP-CSV method (dimethylglyoxime or catechol complexes).Use of the VA Processor and the sample changer allows automatic determination of the above metal ions in one solution. The method has been specially developed for trace analysis in the manufacture of semiconductor chips based on silicon. It can naturally also be employed successfully in environmental analysis.

Determination of chloride, nitrite, nitrate, phosphate, and sulfate in an electroplating bath after inline elimination of heavy metals by cation exchange on the 793 IC Sample Prep Module using anion chromatography with conductivity detection after chemical suppression.

Feedwater for steam generation in boiling water reactors (BWR) needs to be analyzed for corrosion products. Presence of transition metals, mainly nickel and iron, indicates corrosion problems. Traces of these ions are determined using Inline Preconcentration (MiPCT). After separation, post-column reaction with 4-(2-pyridylazo)resorcinol (PAR) allows VIS detection at 510 nm.

The determination of chromium in metal plate samples using anion exchange chromatography with UV/VIS detection after post-column reaction with diphenylcarbazide as per IEC 62321 method for RoHS testing. This method provides procedures for the determination of the presence of chromium(VI) in colorless and colored chromate coatings on metallic samples.

The determination of transition metals by ion chromatography is possible with direct conductivity detection (see AN-C-137) as well as with UV/VIS detection after post-column reaction. Here, the cations are separated as anionic complexes and analyzed after post-column reaction with PAR with subsequent UV/VIS detection. Speciation determination of iron (separation of Fe(II) and Fe(III)) is possible with this procedure. For trace analysis, Metrohm Inline Preconcentration Technique (MiPCT) is applied.

This poster presents an approach that couples a Particle-Into-Liquid-Sampler (PILS) to a dual-channel ion chromatograph (IC) for measurement of aerosol anions and cations and a voltammetric measuring stand (VA) to determine the heavy metals. Feasibility of the PILS-IC-VA online system was demonstrated by collecting aerosol samples in Herisau Switzerland, at defined time intervals; air pollution events were simulated by burning lead- and cadmium-coated sparklers.

The International Standard ISO 17463 describes the determination of the anticorrosive properties of high impedance organic protective coatings on metals. This technique uses cycles composed of electrochemical impedance spectroscopy (EIS) measurements, cathodic polarizations and potential relaxation. This application note shows the compliance of the Metrohm Autolab PGSTAT M204 and flat cell with the standard ISO 17463.

Wine sometimes contains heavy metals which can be precipitated out by the addition of potassium ferrocyanide. Generally, these are quantities of iron ranging between 1 and 5 mg, and exceptionally up to 9 mg Fe/L. Zinc, copper, and lead – in descending order of content – may also be present. To estimate the quantity of potassium ferrocyanide necessary for the «décassage of the wine», only very complicated and relatively inaccurate methods have been described until now.This Bulletin permits accurate results to be obtained easily with a simple instrumentation. The results are available in a short time.

The Metrosep C 4 columns are mainly used for the separation of alkali and alkaline earth metal cations including ammonium and organic amines. Additionally transition metals may be determined.

In the following tables, the half-wave potentials or peak potentials of 90 metal ions are listed. The half-wave potentials (listed in volts) are measured at the dropping mercury electrode (DME) at 25 °C unless indicated otherwise.

The determination of heavy metal ions in a solution is one of the most successful application of electrochemistry. In this application note, anodic stripping voltammetry is used to measure the presence of two analytes, in a sample of tap water.

Metal-organic compounds are commonly used in organic chemistry, for example as Grignard reagents or as strong bases (e.g., butyl lithium compounds). The knowledge of the exact content of reactive species allows to better plan the required amounts for reactions preventing the waste of material or too low yields.This Application Note describes the analysis of metal organics by thermometric titration using 2-butanol as titrant. Due to the strongly exothermic nature of the reaction between 2-butanol with metal-organic compounds, a fast and quantitative analysis of these substances is possible.

Determination of cadmium, copper, lead, and zinc in alkaline plating baths by potentiometric titration with EDTA using the Cu-ISE.

Formaldehyde is determined polarographically at the DME in alkaline solution.

A measured amount of acidic hydrometallurgical leach liquor is treated with potassium oxalate solution to mask potential interference from Fe(III) and other metal ions, and then titrated with standard 1 mol/L NaOH solution.

A measured amount of acidic hydrometallurgical leach liquor is first treated with hydrogen peroxide to oxidize Fe(II) to Fe(III), then with potassium pyrophosphate solution to mask interference from Fe(III) and other metal ions. Ammonium acetate solution is then added as a pH modifier, before being titrated with standardized disodium dimethylglyoximate to an exothermic endpoint.

This Bulletin describes the complexometric potentiometric titration of metal ions. An ion-selective copper electrode is used to indicate the endpoint of the titration. Since this electrode does not respond directly to complexing agents, the corresponding Cu complex is added to the solution. With the described electrode, it is possible to determine water hardness and to analyze metal concentrations in electroplating baths, metal salts, minerals, and ores. The following metal ions have been determined: Al3+, Ba2+, Bi3+, Ca2+, Co2+, Fe3+, Mg2+, Ni2+, Pb2+, Sr2+, and Zn2+.

The Restriction of Hazardous Substances (RoHS) Directive 2002/95/EC stipulates maximum limits for the hazardous metals cadmium, lead and mercury as well as the hexavalent chromium and the brominated flame retardants in electrical and electronic products. To ensure compliance, reliable analysis methods are required.This poster deals with the wet-chemical determination of trace concentrations of the six RoHS-restricted substances in a wide variety of materials including metals, electrotechnical components, plastics and wires. After sample preparation according to IEC 62321, the metals lead, cadmium and mercury are best determined by anodic stripping voltammetry (ASV) and the flame retardants PBB and PBDE are quantified by direct-injection ion chromatography (IC) using spectrophotometric detection. Chromium(VI) can be determined either by adsorptive stripping voltammetry (AdSV) or IC. Both methods are very sensitive and meet prescribed RoHS limits.

Thermometric complexometric titration of metals is often performed with tetrasodium EDTA. This Application Note explains the standardization of tetrasodium EDTA titrant with copper.

Standardization of copper back-titrant using standard tetrasodium EDTA titrant in the determination of metals.

This work was carried out with a Metrosep C 2 - 150 separation column, the following eluent parameters being investigated: nitric, tartaric, citric and oxalic acid concentration and concentration of the complexing anion of dipicolinic acid (DPA). The aim was to determine the effect of these parameters plus that of the column temperature on the retention times of alkali metals, alkaline earth metals, ammonium and amines using ion exchange chromatography with non-suppressed conductivity detection. Due to similar affinities for the ion exchange column, transition metals are difficult to separate with the classical nitric, tartaric, citric and oxalic acid eluents. Partial complexation with the dipicolinate ligand significantly shortens the retention times and improves the separation efficiency. However, too strong complexation results in a rapid passage through the column and thus in a complete loss of separation. Apart from a change in the elution order of magnesium and calcium at high DPA concentrations, other non-amine cations are only slightly affected by the eluent composition. Irrespective of the tartaric acid and nitric acid concentration in the eluent, an increase in column temperature shortens the retention times and slightly improves the peak symmetries of organic amine cations, particularly in the case of the trimethylamine cation. In contrast, an increase in column temperature in the presence of DPA concentrations exceeding 0.02 mmol/L increases the retention time of the transition metals. Depending on the separation problem, variation of the pH value, the use of a complexing agent and/or an increase in column temperature are powerful tools for broadening the scope of cation chromatography.

Polarization resistance (Rp) can quantify the corrosion resistance of metals as an alternative to Tafel analysis. Its methodology and practical use as described in ASTM G59 are discussed.

This Process Application Note is dedicated to the online analysis of zinc, iron and sulfuric acid in several stages of the zinc production process. Additionally, traces of germanium, antimony, as well as several transition metals (e.g., Ni, Co, Cu, Cd) can be precisely determined (<50 µg/L) in the purification filtrates and reactor trains.

Comparative measurements show that the new Metrosep C 4 cation column has even better separation characteristics than the previous Metrosep C 2 and Metrosep Cation 1-2 column types. The Metrosep C 4 column has a clearly improved peak shape which leads to a better separation of the individual peaks. Using Metrosep C 4 the number of theoretical plates per meter was noticeably higher than that obtained on the Metrosep C 2 or C 1-2 column. Additionally for standard cations transition metals and amines, the Metrosep C 4 column shows better results with respect to peak shape, peak height, resolution and asymmetry factor. The clearly improved resolution of the C 4 column with its narrow and high peaks achieves baseline separation for six standard and six transition metal cations. Analysis times and peak areas obtained with the C 4 column are in the same range as those obtained with its predecessors.As a result of the latest production methods and materials, the promising Metrosep C 4 column excels by an outstanding separation performance for complex mixtures comprising standard cations, transition metal cations and amines.

Determination of nickel in refinery and plating solutions. When other metals capable of being complexed by EDTA are present, these will interfere and enhance the result for nickel.

Incineration flue gas requires treatment such as wet scrubbing. The 2060 VA Process Analyzer monitors heavy metals in the scrubbing water, ensuring compliance.

The presence of the hydrated ion [Fe(H2O)6]3+ can interfere with the determination of «free acid» due to the low pKa value (~2.2) of this ion. Ions of metals such as Fe, Cu, and Al can be masked effectively with fluoride, and permit the determination of the acid content by thermometric alkalimetric titration with good accuracy and precision.

This White Paper presents four different «green» sensors: the scTRACE Gold, screen-printed electrodes, the glassy carbon electrode, and the Bi drop electrode from Metrohm that can be used to determine low concentrations of heavy metals in different sample matrices, such as boiler feed water, drinking water, and sea water.

Corrosion refers to a process that involves deterioration or degradation of metal. The most common example of corrosion is the formation of rust on steel. Most corrosion phenomena are of electrochemical nature and consist of at least two reactions on the surface of the corroding metal.

Copper is one of the few metals which is available in nature also in its metallic form. This and the fact that it is rather easy to smelt led to intense use of this metal already in the so-called Copper and Bronze Age. Nowadays, it is more important than ever, because of its good electrical conductivity and its other physical properties. For plants and animals, it is an essential trace element; for bacteria, in contrast, it is highly toxic.This Application Bulletin describes the determination of copper by anodic stripping voltammetry (ASV) using the scTRACE Gold electrode. With a deposition time of 30 s, the limit of detection is about 0.5 μg/L.

The lithium-ion battery market is continuously growing due to the tremendous demand for battery powered consumer products. So-called «NCMs», a mixture of nickel, cobalt, and manganese oxides, have been gathering interest as cathode materials, replacing traditional compounds like cobalt oxides.Quality analysis of the post-sintered materials or recycled batteries can be performed by titration, as demonstrated in this Application Note. A fully automated analysis of the corresponding metals can be performed with OMNIS and its pipetting equipment.

Cu2+, Co2+, Ni2+, Zn2+, and Fe2+/Fe3+ are determined simultaneously. Interference due to the presence of other metals is mentioned, and methods given to eliminate it. The threshold of determination is ρ = 20 µg/L for Co and Ni, and ρ = 50 µg/L each for Cu, Zn, and Fe.

With the advent of electric automobiles, the demand for lithium batteries and with it the demand for lithium material will increase sharply. Brine lakes and hard silicate minerals are numbered among the most important sources of lithium. This Application Note addresses cation determination in seepage water from lithium minerals. Alkali and earth alkali metals are separated in the lithium digestions on the Metrosep C Supp 1 - 250/4.0 column, with subsequent conductivity detection after sequential suppression.

VoltIC Professional 1 is the perfect combination of voltammetry and ion chromatography for the fully automated, simultaneous analysis of anions, cations, and heavy metals (e.g., Zn, Cd, Pb, Cu). The multiple-parameter analysis uses the same "Liquid Handling" elements and a shared sample changer, thus saving on space and costs.

VoltIC pro I is the perfect combination of voltammetry and ion chromatography for the fully automated analysis of anions, cations, and heavy metals (e.g., Zn, Cd, Pb, Cu): comprehensive water analysis on a single system.

Quality and process control of biofuels require straightforward, fast and accurate analysis methods. Ion chromatography (IC) is at the leading edge of this effort. Traces of anions in a gasoline/ethanol blend can accurately be determined in the sub-ppb range after Metrohm Inline Matrix Elimination using anion chromatography with conductivity detection after sequential suppression. While the analyte anions are retained on the preconcentration column, the interfering organic gasoline/bioethanol matrix is washed away.Detrimental alkali metals and water-extractable alkaline earth metals in biodiesel are determined in the sub-ppm range using cation chromatography with direct conductivity detection applying automated extraction with nitric acid and subsequent Metrohm Inline Dialysis. Unlike high-molecular substances, ions in the high-ionic strength matrix diffuse through a membrane into the low-ionic water acceptor solution. In biogas reactor samples, low-molecular-weight organic acids stem from the biodegradation of organic matter. Their profile allows important conclusions concerning conversion in the anaerobic digestion reaction. Volatile fatty acids and lactate can be accurately determined by using ion-exclusion chromatography with suppressed conductivity detection after inline dialysis or filtration.

This Application Note describes the determination of total content of Ba, Ca, Mg, Pb and Zn in unused lubricating oil by means of the Optrode (610 nm). An excess of EDTA is first added to the metals. Afterwards, the excess EDTA is titrated back with magnesium chloride solution up to the end point of the indicator Eriochrome Black T.

For the determination of heavy metals in wine, UV digestion is required to mineralize the sample. The determination of platinum and rhodium is carried out with adsorptive stripping voltammetry (AdSV) at the HMDE.

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of chromium(VI) in electronic components can be carried out by polarography in ammonia buffer pH 9.6.

In gold mining, there is a tendency to switch from cyanide leaching to the much less toxic thiosulfate leaching process. Thiosulfate leaching is a sensitive process that requires more optimization of the components of the leach reaction to maximize gold recovery and reagent loss. Sulfite, thiosulfate, thiocyanate, and tetrathionate are separated on a Metrosep A Supp 5 - 250/4.0 column. Perchlorate is choosen as an eluent as most of the metal perchlorates are soluble in water. This avoids metal precipitation in the IC System.

Determination of free acid in solutions containing metal ions, particularly Fe(III).

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of chromium(VI) in polymer materials can be carried out by polarography in ammonia buffer pH 9.6.

The main sources of nickel pollution are electroplating, metallurgical operations, or leaching from pipes and fittings. Catalysts for the petroleum and chemical industries are major application fields for cobalt. In both cases, the metal is either released directly, or via the waste water-river pathway into the drinking water system. Therefore in the EU the legislation specifies 20 µg/L as the limit value for the Ni concentration in drinking water.The simultaneous and straightforward determination of nickel and cobalt is based on adsorptive stripping voltammetry (AdSV). The unique properties of the non-toxic Bi drop electrode combined with AdSV results in an excellent performance in terms of sensitivity.

Polyols are important raw materials in polyurethane production. Contamination in the raw materials have a great influence on reactions and impair the quality of the end product. Alkali metals are particularly strong catalysts for linear or branched reactions. A rapid and precise method for their simultaneous determination is ion chromatography following Inline Matrix Elimination.

Copper concentrate is an important raw material for copper mills. The concentrate is often contaminated with corrosive fluorine, which is why the fluorine concentration must be checked at regular intervals. A convenient and reliable determination method is Combustion IC in combination with sacrificing vial technology. The sample is placed inside the quartz combustion pipe in a horizontally positioned quartz vial, both ends of which are sealed with glass wool. During combustion, the quartz-destroying components (e.g., fluoride, alkali and earth alkali metals) that are released are captured by the quartz vial and the quartz wool, ensuring that they are thus unable to reach the quartz combustion pipe at all.Keyword: pyrohydrolysis

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of lead and cadmium in electronic components can be carried out by anodic stripping voltammetry (ASV) using ammonium oxalate buffer pH 2.

Heavy metals such as arsenic and mercury find their way into the ground water in many regions of the world, either through natural processes or as the result of human activities. Limit values are exceeded many times over, particularly for arsenic in drinking water, in many areas. This calls for a rigorous monitoring of water quality. The present whitepaper focuses on field determinations of arsenic, mercury, and copper – directly at the sampling site.

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of mercury in electronic components can be carried out by anodic stripping voltammetry (ASV) at a gold rotating disk electrode (Au-RDE).

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulated heavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC 62321 the determination of lead and cadmium in polymer materials can be carried out by anodic stripping voltammetry (ASV) using ammonium oxalate buffer pH 2.

The EU directive on «Restriction of Hazardous Substances» (RoHS) requires the testing of four regulatedheavy metals (Pb, Hg, Cd, Cr(VI)) in electrotechnical products. After sample preparation according to IEC62321 the determination of mercury in polymer materials can be carried out by anodic stripping voltammetry (ASV)at a gold rotating disk electrode (Au-RDE).

Determination of mono-, di-, and trimethanolamine (MMA, DMA, TMA respectively), in the presence of lithium, sodium, ammonium, potassium, magnesium, cesium, calcium, and strontium using cation chromatography with direct conductivity detection.

This Bulletin gives a survey of standard methods from the field of water analysis. You will also find the analytical instruments required for the respective determinations and references to the corresponding Metrohm Application Bulletins and Application Notes. The following parameters are dealt with: electrical conductivity, pH value, fluoride, ammonium and Kjeldahl nitrogen, anions and cations by means of ion chromatography, heavy metals by means of voltammetry, chemical oxygen demand (COD), water hardness, free chlorine as well as a few other water constituents.

Copper is arguably one of the most technologically relevant metals, especially for the semiconductor industry. The deposition process used in this industry is known as the dual-damascene process and it involves the electrodeposition of copper from an acidic cupric compound, in the presence of additives.This Application Note illustrates the use of the Autolab rotating ring disc electrode (RRDE) for the study of electrodeposition of copper and the detection of the Cu+ intermediate.

This Process Application Note deals with the online monitoring of calcium and sulfate in flue gas scrubbing solutions using titration. Other contaminants that can be measured are sulfite, chloride, and chlorine. Low concentrations of heavy metals such as cadmium, zinc, copper, and lead can be measured in the ppb/ppm range with the ADI 2045VA Process Analyzer using voltammetry.

The analytical challenges of environmental analysis increase in difficulty from year to year. As well as analysis of particularly toxic types of metals such as chromium(VI), highly diverse and partially persistent organic fluorine compounds (e.g., trifluoroacetic acid) are presently in focus. The analysis of toxic oxohalides such as bromate and perchlorate is also a current subject of investigation.

In most electrolytes the peak potentials of lead and tin are so close together, that a voltammetric determination is impossible. Difficulties occur especially if one of the metals is present in excess.Method 1 describes the determination of Pb and Sn. Anodic stripping voltammetry (ASV) is used under addition of cetyltrimethylammonium bromide. This method is used when:• one is mainly interested in Pb• Pb is in excess• Sn/Pb ratio is not higher than 200:1According to method 1, Sn and Pb can be determined simultaneously if the difference in the concentrations is not too high and Cd is absent.Method 2 is applied when traces of Sn and Pb are found or interfering TI and/or Cd ions are present. This method also uses DPASV in an oxalate buffer with methylene blue addition.

Corrosion in the water-steam circuit of power plants leads to shorter lifetimes of most metal components and potentially dangerous situations. Flow Accelerated Corrosion (FAC) is a specific case, leading to thinned pipes and elevated Fe concentrations in the circuit. Additionally, metal transport issues such as with Cu from copper heat exchangers can lead to deposition on the high pressure turbine blades, decreasing their efficiency. Current methods can monitor but not prevent these issues, and analysis times are extremely long (up to three weeks). In combination with the power plant’s Distributed Control System (DCS), online monitoring of Fe and Cu with the 2060 Process Analyzer from Metrohm Process Analytics ensures that corrosion can be controlled before it affects the power plant efficiency, ultimately decreasing downtime and lowering maintenance costs. Results are offered within 20 minutes, allowing fast adjustments to the water-steam circuit to protect company assets.

Anodizing metal surfaces improves resistance against corrosion and wear. Etching baths can be monitored precisely online with the 2060 TI Process Analyzer or 2026 HD Titrolyzer.

Silver is an important metal not only in jewelry and silverware but also in electrical conductors and contacts. The knowledge of the exact silver content in fine silver and silver alloys ensures that quality standards for jewelry and silverware are met. As for the plating industry, the knowledge of the amount of silver in silver plating baths helps to run the bath efficiently.While X-ray fluorescence (XRF) is a fast alternative to determine the silver content in fine silver and silver alloys, it can only determine the silver content of the outermost sections of the metal. In contrast, titration offers a more comprehensive solution considering the whole sample, thus preventing fraud by thick plating.This application bulletin describes the potentiometric determination of silver in fine silver and silver alloys accordingto EN ISO 11427, ISO 13756, GB/T 17823, and GB/T 18996 as well as in silver plating baths by a titration with potassium bromide or potassium chloride, respectively

This Application Bulletin describes the voltammetric determination of the elements iron, copper and vanadium. Fe as well as Cu and V can be determined as catechol complex at the HMDE by adsorptive stripping voltammetry (AdSV). Fe(II) and Fe(III) are determined as Fe(total) with the same sensitivity for both species in either phosphate buffer or PIPES electrolyte. Cu and V can be determined in PIPES buffer.The methods are primarily suitable for the investigation of ground, drinking and surface waters, in which the concentration of these metals is important. But the methods can naturally also be used for trace analysis in other matrices.The limit of detection for all three elements in PIPES buffer is 0.5 ... 1 µg/L, for iron in phosphate buffer it is approx. 5 µg/L.

Electroplating processes are used in several different industry sectors to protect the surface quality of various products against corrosion or abrasion and significantly improve their working life. It is essential to check the bath composition on a regular basis to ensure that the process is operating correctly. Typical examples of electroplating baths include alkaline degreasing baths or acidic or alkaline baths containing metals e.g. copper, nickel, or chromium, or components like chloride and cyanide. It is crucial that the chosen analysis technique fulfills high safety standards for these kinds of analyses and produces reliable results. The OMNIS Sample Robot system automatically pipettes and analyzes aggressive electroplating bath samples on different workstations, increasing the safety in the lab. This provides more reliable results in comparison to manual titration and is more time efficient as different parameters can be analyzed in parallel.

Determination of copper, principally in copper mining and refining solutions. The method may also be used fordetermination of purity of copper metal. Optimal results are obtained when aliquots containing copper in the rangeapproximately 3 - 6 mmol Cu are titrated.

Formaldehyde can be determined reductively at the DME. Depending on the sample composition it may be possible to determine the formaldehyde directly in the sample. If interferences occur then sample preparation may be necessary, e.g. absorption, extraction, or distillation.Two methods are described. In the first method formaldehyde is reduced directly in alkaline solution. Higher concentrations of alkaline or alkaline earth metals interfere. In such cases the second method can be applied. Formaldehyde is derivatized with hydrazine forming the hydrazone, which can be measured polarographically in acidic solution.

Heavy metals, particularly cadmium and lead, are known to be highly toxic to humans. Therefore, controlling the cadmium and lead content in drinking water is of utmost importance. In many countries, the limit in drinking water for cadmium is between 3–5 µg/L, and for lead it is between 5–15 µg/L. These trace concentrations can reliably be determined with the method described in this Application Bulletin. The determination is carried out by anodic stripping voltammetry (ASV) using the non-toxic Bi drop electrode in a slightly acidic electrolyte.

The analytical challenge treated by the present work consists in detecting sub-ppm quantities of bromide, sulfate, aliphatic monocarboxylic acids and several alkaline earth metals in the presence of very high concentrations of sodium and chloride. Bromide, sulfate, acetate and butyrate can be reliably determined by suppressed conductivity detection. Due to matrix effects, propionate can only be detected qualitatively. This drawback can be overcome by coupling the ion chromatograph (IC) to a mass spectrometric (MS) detector. This results in reduced matrix interferences and significantly enhanced sensitivities. The cations magnesium, barium and strontium are determined by non-suppressed conductivity detection.

Thallium and cadmium can be determined by anodic stripping voltammetry (ASV) at the HMDE (Tl) and polarography at the DME (Cd), respectively using aqueous hydrochloric acid as supporting electrolyte. Since Cd is present in high excess and would therefore interfere with the determination of thallium, a post electrolysis procedure is applied to remove the co-deposited metal from the mercury drop.

A corrosion inhibitor is a substance that reduces the corrosion rate of a metal. A corrosion inhibitor is usually added in a small concentration to the corrosive environment. This application note shows how Metrohm Autolab instruments can be used to check the quality of inhibitors.

Lithium is a soft alkali metal that is typically obtained from salt lake brines. Lithium is used for many applications, but especially for production of lithium-ion batteries in electric cars, mobile phones, and more. This Process Application Note presents a method to monitor lithium as well as other cations in brines by online process ion chromatography (IC), a multiparameter analytical technique that can measure ionic analytes in a wide range of concentrations.

The ASTM B825 is used to determine the corrosion and tarnish film on metal surfaces. This is achieved by using the so-called cathodic reduction method. With the help of a Metrohm Autolab PGSTAT302N and a Metrohm Autolab 1 L corrosion cell, a procedure to replicate the ASTM B825 is shown.

This Application Note presents a complementary method that allows a consecutive determination after the sample preparation (digestion) of both metal ions in one beaker with an optical sensor and xylenol orange as an indicator.

Nickel is widely used in stainless steel production. At high enough concentrations, it is known to cause allergic reactions when in contact with skin. Drinking water may be contaminated by taps which are made from metals containing nickel. The guideline value for nickel in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to 70 μg/L. National limit values of typically lower at e. g. 20 μg/L. Cobalt usually occurs associated with nickel and can be found in smaller concentrations besides nickel. Adsorptive stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) for the determination of nickel and cobalt in drinking water. While AAS (and competing methods) can only be performed in a laboratory, adsorptive stripping voltammetric determinations can be used in the laboratory or alternatively in the field with the 946 Portable VA Analyzer. The determination is carried out on a bismuth film applied to the scTRACE Gold electrode.

Ion chromatography mass spectrometry (IC-MS) is a powerful tool that can handle many challenging analytical tasks which cannot be performed adequately by IC alone. IC-MS is a robust, sensitive, and selective technique used for the determination of polar contaminants like inorganic anions, organic acids, haloacetic acids, oxyhalides, or alkali and alkaline earth metals. After separation of the sample components via IC, mass selective detection guarantees peak identity with low detection limits. The inclusion of automated Metrohm Inline Sample Preparation (MISP) allows not only water samples, but also chemicals, organic solvents, or post-explosion residues to be readily analyzed without need for extensive manual laboratory work. This White Paper explains the benefits of IC-MS over IC in certain cases, the hyphenation of IC and different MS systems, as well as related norms and standards.

Clay is used for the manufacture of roofing tiles. Quality controls during this process require the determination of halogen and sulfur content. This is ideally accomplished using Metrohm Combustion IC. With this method, the sulfur is determined as sulfate and the halogens as halogenides. Because clay often contains high contents of alkali and earth alkali metal ions that attack the pyrolysis tube, tungsten oxide is added prior to combustion.Keyword: pyrohydrolysis

This Application Note describes the simultaneous determination of the four most important analysis parameters of paint dryers – cobalt and solids contents, specific weight and viscosity – using a VIS-NIR analyzer. The visible range correlates with the metal content, while the NIR region provides the specific weight, viscosity and solids content.

Chrome plating is an important electroplating technique that covers metal or plastic surfaces with a thin layer of chromium for both protection and decoration purposes. The sulfate and sulfuric acid concentrations in the baths are important parameters in the coating process and require continuous monitoring. The anions in the chrome baths are separated on the Metrosep A Supp 5 - 250/4.0 column and are determined using conductivity detection in accordance with sequential suppression.

This Bulletin describes the simultaneous determination of gold and copper by potentiometric titration using an Fe(II) solution as titrant. Fe(II) reduces Au(III) directly to the free metal, whereas Cu(II) does not react. By the addition of fluoride ions the Fe(III) is complexed and a shift of the redox potential is effected. Afterwards, potassium iodide is added, thus reducing the Cu(II) to Cu(I), and the free iodine is again titrated with the Fe(II) solution using a Pt Titrode.Chemical reactions:Au(III) + 3 Fe(II) → Au + 3 Fe(III)2 Cu(II) + 2 I- → 2 Cu(I) + I2I2 + 2 Fe(II) → 2 I- + 2 Fe(III)

Speciation analysis is an important tool in analytical chemistry giving information about the quantitative distribution of different oxidation states of one and the same metal ion. The speciation of iron(II) and iron(III) (Fe 2+/Fe 3+) is achieved by ion chromatographic separation of their anionic dipicolinic acid complexes. Afterwards, post-column reaction with 4-(2-)pyridylazo-resorcinol (PAR) allows VIS detection at 510 nm.

In pressurized water reactors (PWRs), light water is used as coolant in the primary side. Boron (as boric acid) is added to the coolant to absorb neutrons, thus controlling reactivity. Lithium hydroxide assures the alkaline pH value to prevent corrosion. This application allows to measure lithium content besides high boric acid concentrations. AN-C-138 shows the respective trace metal determination on the same system setup.

Lanthanum (La) is a transition metal which oxidizes easily in air to lanthanum(III) oxide. This oxide, as well as salts resulting from its dissolution in acid and recrystallization, is a component of different catalysts. Here, a lanthanum(III) acetate solution prepared by dissolution of lanthanum(III) oxide in acetic acid, has to be tested for a sodium contamination. The high concentration of La3+ is complexed by the dipicolinic acid in the eluent and forms anionic complexes. These complexes are eluted in the front and therefore do not interfere with the sodium impurity as well as other cations such as ammonium and calcium.

Lithium is a soft metal which is used for many applications, such as production of high-temperature lubricants or heat-resistant glass. Furthermore, lithium is used in large quantities in for battery production. It is obtained from brines and high-grade lithium ores. Depending on the lithium concentration, extraction may or may not be economically viable.This Application Note demonstrates a method to determine the lithium concentration in brines by potentiometric titration. Lithium and fluoride precipitate in ethanol as insoluble lithium fluoride. Using ammonium fluoride as the titrant and a fluoride ion-selective electrode (ISE), determination via potentiometric titration is possible. This method is more reliable, faster, and less expensive than the determination of lithium in brine by other more sophisticated techniques such as atomic absorption spectroscopy (AAS).

This Bulletin describes the simultaneous potentiometric titration of free boric acid and free tetrafluoroboric acid in nickel plating baths. After addition of mannitol, the formed mannitol complexes are titrated with sodium hydroxide solution. The determination is carried out directly in the plating bath sample; nickel and other metal ions do not interfere.

The combination of ion chromatography and inductively coupled plasma mass spectrometry (IC-ICP/MS) is ideally suited for the detection of species of arsenic and mercury in their various oxidation levels and forms of chemical bonding. However, some species – as in the case of mercury – are reciprocally converted into one another during sample preparation, thus making a determination of the initial concentrations of the heavy metal species impossible. This article shows how these interconversions can be calculated with isotope dilution analysis and IC-ICP/MS in accordance with EPA method 6800.

To reduce the toxic effects of cadmium on the human body, as well as to limit the neurotoxic effects of lead, the provisional guideline values in the World Health Organization’s «Guidelines for Drinking-water Quality» are set to a maximum concentration of 3 µg/L for cadmium and 10 µg/L for lead. The completely mercury-free Bi drop electrode takes the next step towards converting voltammetric analysis into a non-toxic approach for heavy metal detection. Using this environmentally friendly sensor for anodic stripping voltammetry (ASV) allows the simultaneous determination of Cd and Pb in drinking water. The outstanding sensitivity is more than sufficient to monitor the provisional WHO guideline values.

Lead is known to be highly toxic and lead salts are easily absorbed by creatures. By interfering with enzyme reactions,lead can affect all parts of the human body. It can cause severe damage to brain and kidneys and can cross the bloodbrain barrier. Cases of chronic lead poisoning caused by lead metal used in the water piping system are well known. Therefore, the control of drinking water for lead content is of utmost importance. In many countries (e.g., EU, USA), the limit for lead in drinking water is between 10 and 15 μg/L. These concentrations can reliably be determined with the method described in this Application Bulletin. The determination is carried out by anodic stripping voltammetry at a silver film applied to the scTRACE Gold electrode.

Mercury and its compounds are toxic. The highest risk is posed by chronic poisoning with mercury compounds ingested with food. A significant part of the mercury present in the environment is of anthropogenic origin. Considerable sources are coal-fired power plants, steel, and nonferrous metal production, waste incineration plants, the chemical industry, or artisanal gold mining where the use of elemental mercury for the extraction of gold from the ore is still common. The guideline value for inorganic mercury in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to 6 μg/L.With a limit of detection (LOD) of 0.5 μg/L, anodic stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS).While AAS (and competing methods) can only be performed in a laboratory, anodic stripping voltammetry can be used conventionally in the laboratory or alternatively in the field with the 946 Portable VA Analyzer. The determination is carried out on the scTRACE Gold electrode.

A measured amount of acidic hydrometallurgical leach liquor is further acidified with sulfuric acid, prior to being titrated with standard potassium dichromate solution to an exothermic endpoint. Thus, 1 mol K2Cr207 ≡ 6 mol Fe2+.

A measured amount of acidic hydrometallurgical leach liquor is pH modified with a small amount of glacial acetic acid, and the Fe(III) content reduced to Fe(II) with iodide ion. The liberated iodine is titrated with standard thiosulfate solution to an exothermic endpoint. Thus, 1 mol Fe3+= 1 mol S2O32-.

A measured amount of acidic hydrometallurgical leach liquor is treated first with a complexing agent (sodium gluconate). It is then basified to ~pH 10.5 with a NH3 /NH4Cl buffer, prior to the addition of KCN solution to mask Fe(III). Caution! Do not add KCN to solutions of pH below 9! The Fe(III) is then reduced to Fe(II) by additon of ascorbic acid, prior to titrating the Mg content with standard Na4EDTA solution.

The presence of copper in fuel ethanol blends has gained considerable attention, since Cu2+ catalyzes oxidative reactions in gasoline leading to a deterioration of olefins and the formation of gum. Anodic stripping voltammetry (ASV), one of the most sensitive and accurate techniques for trace-metal analysis, has been demonstrated for the determination of Cu(II) in ethanol/gasoline blends without any sample pretreatment. Copper ions are first electrodeposited onto the surface of a hanging mercury drop electrode (HMDE) before the amalgamated copper is quantitatively stripped (anodically dissolved), a current-voltage curve being recorded.Experimental conditions such as deposition time and potential as well as the suitable electrolyte and reference electrode were determined in preliminary experiments. For synthetic samples spiked with Cu2+ (5…100 µg/L), recovery rates between 96 and 112% were obtained. The copper-spiked E85 sample provided a recovery of 100%. The relative standard deviations for Cu2+ concentrations of 5 µg/L and above were 8.0 and 5.5% respectively. Using a preconcentration time of 60 s at -0.7 V versus Ag/AgCl, a linear range of 0…500 µg/L with a detection limit of 2 µg/L was obtained.

This Application Bulletin describes two methods for the determination of iron at the Multi Mode Electrode.Method 1, the polarographic determination at the DME, is recommended for concentrations of β(Fe) > 200 μg/L. For this method the linear range is up to β(Fe) = 800 μg/L.For concentrations < 200 μg/LMethod 2, the voltammetric determination at the HMDE, is to be preferred. The detection limit for this method is β(Fe) = 2 μg/L, the limit of quantification is β(Fe) = 6 μg/L. The sensitivity of the method cannot be increased by deposition.Iron(II) and iron(III) have the same sensitivity for both methods.These methods have been elaborated for the determination of iron in water samples. For water samples with high calcium and magnesium concentrations such as, for example, seawater, a slightly modified electrolyte is used in order to prevent precipitation of the corresponding metal hydroxides. The methods can also be used for samples with organic loading (wastewater, beverages, biological fluids, pharmaceutical or crude oil products) after appropriate digestion.

Metal precipitation and cyanide recovery in the SART process (sulfidization, acidification, recycling, thickening) depend to a great extent on the sulfide concentration. Among the flow injection analysis methods coupled to wet-chemical analyzers, the combination of a gas diffusion cell with an ion chromatograph (IC) plus subsequent direct spectrophotometric detection has proven to be one of the most convenient methods of sulfide analysis.This paper deals with the determination of sulfide anions via the coupling of a gas diffusion cell to an IC with subsequent spectrophotometric detection.

Substrates for surface-enhanced Raman spectroscopy (SERS) are typically fabricated with complex (micro/nano)structures of noble metals, enabling trace level detection of analytes. Due to the high costs and reactivity of these SERS substrates, they often have a limited shelf life. Development of new substrate materials which minimize these issues yet maintain the same performance standards is a constant concern.Screen-printed electrodes can be easily fabricated using different metallic materials with the well-established screen-printing method, leading to mass production of versatile, cost-effective, and disposable devices. In this Application Note, the feasibility of using readily-available screen-printed metal electrodes as suitable substrates for the fast and sensitive detection of different chemical species by in situ electrochemical SERS (EC-SERS) is shown.

Corrosion of metallic components is an inherent problem for engines, because metals naturally tend to oxidize in the presence of water and/or acids. Increased acid content is indicated by a low pH value, and could lead to a variety of problems like a shorter storage life (stability) or a reduced buffer capacity of the used engine coolant or antirust.In this Application Note, engine coolants or antirust samples are dissolved in water, and the pH measurement using the Profitrode is carried out according to ASTM D1287.

Corrosion of metallic components is an inherent problem for engines, because metals naturally tend to oxidize in the presence of water and/or low pH value. The reserve alkalinity of engine coolants and antirusts is a measure of the buffering ability to absorb acidity. The reserve alkalinity is frequently used for quality control during production and often listed in the specifications of the coolants. A fast and accurate determination is therefore important.This Application Note describes the straightforward determination of reserve alkalinity according to ASTM D1121. Using a fully automated system allows an accurate and reliable determination due to the reduction of human errors. Furthermore, the operator is free to carry out other tasks increasing the efficiency of the laboratory.

Determination of aluminum in an acidic extract containing metals (e.g., alkali, alkaline earth, iron, chromium, molybdenum, etc.) using cation chromatography with UV detection after post-column reaction with Tiron.

Tin can be determined in wastewater by anodic stripping voltammetry (ASV) in oxalate buffer after addition of methylene blue. Samples with organic substances have to undergo UV digestion before analysis. Samples with higher concentrations of metals can be diluted before digestion.

The shelf life of foods and beverages depends among other things on the packaging material used. Metals are ideally suitable for packaging, as they can be laminated with various passivating and food-compatible layers. Electrochemical measurements such as Electrochemical Impedance Spectroscopy (EIS) make it possible to check the layers for damage.

The high-capacity Metrosep C 6 - 150/4.0 cation column convinces with outstanding separations, narrow peaks, and a multitude of available eluents. In this Note, the selectivity for alkali, earth alkali, and certain transition metals, in addition to methyl and ethanol amines, is shown using a nitric acid eluent and direct conductivity detection.

This document describes a very simple procedure that can be used to produce small deposits of platinum on a goldsubstrate. This simple procedure is based on an electrochemical process known as displacement deposition, during which the deposition of a noble metal occurs by the oxidation of a precursor metal adlayer deposited on the substrate, at open circuit potential (OCP).

The determination of cyanide and sulfide in the trace range requires an alkali eluent and amperometric detection. This Application Note describes a new column/eluent combination for optimized separation. The combination consists of the Metrosep A Supp 10 - 100/2.0 Microbore Column and a sodium hydroxide eluent that contains traces of EDTA for the complexation of the transition metals. This yields a better peak shape and detection limits below 0.05 µg/L.

Sulfide and cyanide are toxic anions. Their trace determination in any kind of water samples, especially in wastewater, is requied for safety reasons. However, metal traces present in the eluent can mask target anions due to complexation. The addition of a stronger complexing agent to the eluent mask these metal cations enabling interference free determaination. This application is mainly used for the analysis of cyanide and/or sulfide in water. However, it also fulfills the requirements of ASTM D2036 for the determination of total, amenable, weak acid dissociable cyanides. The determination of cyanide and sulfide require an alkaline eluent and amperometric detection. This Application Note describes a new column/eluent combination for optimized separation. The combination consists of the Metrosep A Supp 10 - 100/4.0 column and a sodium hydroxide eluent containing a trace of EDTA for transition metal complexation. This yields in better peak shape and detection limits below 0.1 μg/L.

The synthetic rubber known as Bromobutyl (BIIR) has many of the attributes of butyl rubber, but has better adhesion to other rubbers and metals, resulting in substantially faster cure rates. The simultaneous quantification of the bromine content, Mooney viscosity, volatile content, calcium stearate content, and functional bromide in BIIR can be easily performed with near-infrared spectroscopy (NIRS) without the use of chemicals.

Sulfur species are critical contaminants in ammonia gas. They can cause high-temperature sulfidation of metals, form aggressive complexes with other elements, or react subsequently in processes where the ammonia gas is used. The concentration of such impurities tends to be very low, but they may not exceed critical levels of 0.5 mg/L. Although this level is very close to the system blank of the Combustion IC system, the setup can be used to prove that such critical limits are not exceeded.

It is essential to know before starting the sample analysis if the electrode is in a good state or not. A well workingelectrode will increase the quality of your results, as the accuracy and precision will be increased. Furthermore, tedious error tracking can be omitted and no sample is wasted due to a defect or old electrode. There exist several ways how to check metal electrodes, e.g., measurement of redox potentials, potentiometric titration or bivoltammetric titration. This bulletin describes the best methods for the various by Metrohm available metal electrodes.

Ethanol, bio-ethanol and biofuel (E85) are increasingly used as substitutes for petroleum-based fuels. During storage, they often come into contact with metallic substrates or surfaces, e.g., in barrels, tanks, or other containers. Excessive concentrations of ions in the stored fuel promotes corrosion. Monitoring the total concentration of the ions present in the fuel matrix should be the first step of an effective anti-corrosion strategy.An easy, fast, and cost-effective method to determine the total amount of ions is by measuring the electrical conductivity according to DIN 15938.

Measures to monitor or prevent corrosion are crucial in nuclear power plants, where significant risks to health and safety can occur if corrosion is left unchecked. Anions corrode metals under high temperature and pressure, therefore their concentrations must be monitored at all times. The analytical challenge in the primary circuit is detection of anions in the μg/L range alongside gram quantities of boric acid and lithium hydroxide. Precise, reliable trace analysis requires the method to be automated as much as possible. The 2060 IC Process Analyzer from Metrohm Process Analytics can measure several anions from a single injection, with combined Inline Preconcentration and Inline Matrix Elimination to measure low anion concentrations precisely and reliably time after time.

Electrochemical Raman (EC-Raman) spectroscopy enhances comprehension of energy storage devices by tracking physicochemical changes. This note details EC-Raman findings during nickel-metal hydride (NiMH) battery charge and discharge simulations.

It is a comparatively easy matter to coat platinum electrodes with platinum black by electrolytic deposition of the metal from a platinizing solution.

The simultaneous ion chromatographic determination of trace-levels of lanthanides (or lanthanoides) was achieved by using either direct non-suppressed conductivity detection or UV/VIS detection after post-column reaction (PCR) with arsenazo III at 655 nm. Conductivity detection under isocratic conditions resulted in an overall analysis time of approx. 70 minutes. In contrast, the determination of the lanthanides via gradient elution and subsequent spectrophotometric detection of the arsenazo III-lanthanide(III) complexes was performed within 22 minutes. Besides the outstanding analysis time, UV/VIS detection excelled by its enhanced selectivity and sensitivity and did not suffer from interferences by ubiquitous non-lanthanide impurities such as iron(III) or other transition metals. For both conductivity and spectrophotometric detection, the inclusion of sample preconcentration steps lowered the limit of detection (LOD) to the sub-ppb range.

Gold leaching by cyanidation requires precise monitoring of cyanide and gold. Online process analyzers perform such measurements, improving safety and compliance.

The 2060 XRF Process Analyzer continuously monitors elemental concentrations online within zinc-nickel electroplating baths to precisely guide chemical dosing.

Complexing agents such as EDTA are used in soaps and other detergents in order to remove unwanted metal ions and to lower water hardness. The EDTA content in soaps and detergents can be determined using potentiometric titration with copper sulfate as titrant and the Cu-ISE as electrode.

This Application Note explains how the 2060 XRF Process Analyzer enables real-time chemical monitoring of copper, tin, and zinc concentrations in white bronze plating baths.

Zirconium can be analyzed quickly and easily in slightly acidic solutions with back titration. The ion-selective copper electrode is used in this Application Note to determine zirconium in aqueous solution.

"A sensitive methods to determine manganese is described. It is primarily suitable for the investigation of ground, drinking and surface waters, in which the concentration of manganese is important. The method can naturally also be used for trace analysis in other matrices.Manganese is determined in an alkaline borate buffer by the anodic stripping voltammetry (ASV). Interference by intermetallic compounds is prevented by the addition of zinc ions in the sample. The limit of determination lies at b(Mn) = 2 µg/L."

The 800 Dosino controlled by tiamo™ or Touch Control can be used universally for dosing and liquid handling tasks in both the analytical laboratory or directly in the synthesis laboratory. This poster looks at three typical liquid handling applications, the synthesis of metal-organic compounds, the preparation of standards, and the determination of pharmaceutical ingredients.

Hydrogen peroxide is used as a cleaning, oxidizing and bleaching agent. Depending on its purity, it may contain inorganic anions as well as organic acid anions, such as oxalate, phthalate, and dipicolinic acid. Dipicolinic acid is a complexing agent that binds transition metal cations and is sometimes added to increase the stability of hydrogen peroxide.

Free white paper describes the effective use of electrochemical techniques to measure corrosion and the effectiveness of inhibitors.

Pickling baths are used in the galvanic industry to clean steel surfaces and prevent corrosion through passivation. Maintaining specific Fe2+/Fe3+ and free acid/total acid ratios is vital to ensure the baths' optimal performance, which directly impacts the final product quality and reduces production costs by minimizing reagent consumption. This application presents a method to regularly monitor the acid and iron composition in pickling baths online by using a process analyzer from Metrohm Process Analytics.

Controlling Au(I) levels in gold plating baths is required for high quality. Voltammetric analysis with the Multi-Mode Electrode Pro is an efficient solution.

In power plants, corrosion is the primary factor leading to costly and critical downtimes. In a nuclear power plant, a separate water circuit known as the Pressurized Water Reactor (PWR) ensures radioactive material stays contained while still transferring heat and energy to the other circuits. Boric acid and lithium hydroxide are added specially to the PWR circuit in amounts which can complicate other analytical measurements. Lithium prevents corrosion and must be monitored, along with other cations such as zinc, nickel, and ammonium. In order to measure these cations online at sub-µg/L range in a single analysis, the 2060 IC Process Analyzer is offered with combined Inline Preconcentration and Inline Matrix Elimination. Several cations can be analyzed in a single injection, with automated sample preparation making precise and reliable measurements easier.

Nitrilotriacetate (NTA) is a complexing agent that is used in detergents as a water softener. NTA forms complexes with metal ions such as Ca2+, Cu2+ and Fe3+ and thus prevents the formation of lime and its deposits. The NTA content is therefore an important parameter for the quality of detergents and is determined using back titration of an excess of copper nitrate.

The Devanathan-Stachurski cell (or «H cell») is successfully used to evaluate the permeation of hydrogen through sheets or membranes. As small amounts of hydrogen pass through the sheet or membrane, a very sensitive potentiostat is required for its detection. A study of the hydrogen permeation properties of different iron sheets is discussed in this Application Note while taking the instrumental requirements into account.

Abrasive machining of e.g., metal parts requires a cooling lubricant. Their purpose besides cooling and lubrication is to inhibit corrosion. Amines are added to the emulsion to keep the pH high. In the actual application, DCHA and MDCHA have to be analyzed besides other amine components and inorganic cations. To avoid oil contamination on the IC system, Inline Dialysis is applied. The detection is performed by direct conductivity detection.

The Bayer Process is the method used to refine alumina from bauxite ore, as smelting aluminum directly from alumina is much more cost- and energy-effective. In this process, "aluminate liquors" are created by digesting the crushed bauxite with CaO and NaOH at high temperatures. Additionally, the CaO causticizes carbonate which forms in the alkaline solution from organic degradation and CO2 absorption from the atmosphere. Contaminations are removed at various steps in the process, and the liquor is filtered from the alumina crystals before it is recycled back to the digestion step. Before the spent liquor can be reused, a determination of the concentrations of the total hydroxyl (“caustic”), carbonate, and alumina values is required. These parameters can be determined quickly via thermometric titration with the 2035 Process Analyzer.

White paper on monitoring corrosion and the benefits of online or inline chemical analysis over manual sampling and offline laboratory methods for corrosion monitoring. Online and inline process application solutions for corrosion prevention with related application notes for further information are presented.

In an electroless plating bath, the consumed ingredients have to be regularly replenished to ensure an even layer of nickel-phosphorus alloy. This requires online monitoring of the active bath constituents. Parameters to be controlled are pH value (4.5–5.0) as well as nickel (NiSO4 < 10 g/L) and hypophosphite concentration (NaH2PO2: 1–12%). Other measurement options include sulfate, alkalinity, and organic additives (via CVS).

This Application Bulletin describes the determination of zinc at a mercury film electrode (MFE). Zinc can also be determined simultaneously with cadmium and lead. The determination of copper at the MFE is not possible. The mercury film is plated ex-situ on a glassy carbon electrode and can be used for half a day up to one day.Zinc can be determined at the mercury film electrode by anodic stripping voltammetry (ASV). The presence of copper, which is naturally present in many samples, affects the determination of zinc due to the formation of an intermetallic compound. As a result the determined concentrations of zinc are too low. The addition of gallium can eliminate the interference to a certain extent since the intermetallic complex of gallium and copper is more stable than the complex of zinc and copper.With a deposition time of 10 s, the limit of detection is β(Zn2+) = 0.15 μg/L. The linear working range goes up to approx. 300 μg/L.With the deposition time of 10 s the method is suitable for samples between 10 μg/L and 150 μg/L Zn content. For samples with lower concentrations the results are more reliable if the deposition time is increased to e.g. 30 s. Samples with higher concentrations have to be diluted.

This Application Note explains how fluoride determination in acid etching baths can be performed with thermometric titration.

This poster describes a simple and sensitive method for the determination of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in water samples by suppressed conductivity detection. Separation was achieved by isocratic elution on a reversed-phase column thermostated at 35 °C using an aqueous mobile phase containing boric acid and acetonitrile. The PFOA and PFOS content in the water matrix was quantified by direct injection applying a 1000 μL loop. For the concentration range of 2 to 50 μg/mL and 10 to 250 μg/mL, the linear calibration curve for PFOA and PFOS yielded correlation coefficients (R) of 0.99990 and 0.9991, respectively. The relative standard deviations were smaller than 5.8%.The presence of high concentrations of mono and divalent anions such as chloride and sulfate has no significant influence on the determination of the perfluorinated alkyl substances (PFAS). In contrast, the presence of divalent cations, such as calcium and magnesium, which are normally present in water matrices, impairs PFOS recovery. This drawback was overcome by applying Metrohm`s Inline Cation Removal. While the interfering divalent cations are exchanged for non-interfering sodium cations, PFOA and PFOS are directly transferred to the sample loop. After inline cation removal, PFAS recovery in water samples containing 350 mg/mL of Ca2+ and Mg2+ improved from 90…115% to 93…107%.While PFAS determination of low salt-containing water samples is best performed by straightforward direct-injection IC, water rich in alkaline-earth metals are best analyzed using Metrohm`s Inline Cation Removal.

Manganese in drinking water is determined by anodic stripping voltammetry (ASV) at the HMDE. The measurement is performed in an alkaline solution and zinc solution is added to prevent interference from intermetallic compounds.

Harmful industrial flue gases like H2S and CO2 cause corrosion of pipes and damage the environment. Adding the correct amount of amines in scrubber solutions, e.g. ethanolamines and methylamines, will neutralize these gases («gas sweetening»). Non-suppressed cation analysis with direct conductivity detection is a straightforward and robust technique for the quantification of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA) via ion chromatography. Thanks to the high capacity of the Metrosep C 6 column, large volumes can be injected without compromising the peak shapes. The analytical technique can be used at laboratory scale but also for process analysis.

This Application Note explains how to use magnesium to standardize tetrasodium EDTA titrant.

Electroless nickel plating ensures low-cost wear and corrosion resistance. Monitoring lead stabilizer levels in Ni plating baths is possible with the Bi drop electrode.

One way to maximize heat transfer efficiency and reduce costs in a power plant is by controlling the water chemistry in the cooling circuit. This cooling water is kept alkaline to maintain the protective oxide layer on the metal piping throughout the water circuit. However alkalinity above the recommended range increases the probability of scale formation (deposition), so it is buffered with carbonate (CO32-) and bicarbonate ions (HCO3-). Titration of the cooling water to pH 4.5 gives the so-called "M-Alkalinity" (methyl orange alkalinity), a measure of total alkalinity. Below this pH, there is no more alkalinity present, only free acid (H+), carbonic acid (H2CO3), and CO2.

Lead is known to be highly toxic, and lead salts are easily resorbed by humans. Cases of chronic lead poisoning caused by lead metal used in the water piping system are well known. Therefore, the control of drinking water for lead content is of utmost importance. The Lead and Copper Rule (LCR) published by the USEPA (United States Environmental Protection Agency) states an action limit of 15 μg/L lead for drinking water. Using a portable voltammetric instrument, lead can be determined in these concentrations directly at the point of sampling.

The TSC SW closed and TSC battery cells are compact systems designed for measurement of air or moisture sensitive materials, such as those materials used in rechargeable batteries. These cells offer well-controlled environment for the in-temperature measurement of solid and gel like materials in contact with metal electrodes in planar geometry. For example, battery active materials, ionically conductive solid-state electrolytes and battery separators can be tested using these cells. In this experiment, standard resistors of 100 Ω are used in both cells to understand the cell effects, if any, on the measurements.

Explore how to construct simple and complex equivalent circuit models for fitting EIS data in this Application Note. Nyquist plots are shown for each example.

In this Application Note, hydrogen permeation experiments are conducted following the procedure described in the ASTM standard G148.

A nickel metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but, for the anode, instead of cadmium, it has a hydrogen absorbing alloy. Like in NiCd batteries, nickel is the cathode. The voltage output of such packs is directly proportional to the number of single cells in the pack. In some cases, the total voltage can exceed the maximum of 10 V that is measurable by the Autolab potentiostat/galvanostat. To apply and measure voltages greater than 10 V, we have developed a voltage multiplier that increases the voltage range of the Autolab.

Copper is used widely in industrial cooling water systems for its heat transfer properties, although it is susceptible to corrosion. Corrosion can cause a loss of efficiency and eventually a failure of equipment, leading to costly maintenance, replacement, and downtime. Corrosion inhibitors (triazoles) can be added to the water chemistry, which form sparingly soluble protective layers on the surface of the metal. Triazole concentrations must be maintained to protect the copper, which necessitates regular concentration determinations in cooling water. The 2060 IC Process Analyzer with UV/VIS detection is well-suited for this application, able to precisely and reliably measure multiple ionic and UV-active compounds simultaneously in cooling water.

The rotating cylinder electrode (RCE) is a technique used in corrosion research to simulate in a laboratory environment the turbulent flow which usually occurs when liquids are transported through pipelines. The RCE is used to generate a turbulent flow at the surface of a sample, simulating the pipe flow conditions. Experiments that involve an RCE are regulated by the ASTM G185 standard. In this application note, The RCE with a 1018 carbon steel cylinder sample was used with the linear polarization (LP) measurement technique.

Here, the most common circuit elements for EIS are introduced which may be assembled in different configurations to obtain equivalent circuits used for data analysis.

The presence of iron in drinking water can lead to an unpleasant taste, stains, or even growth of «iron bacteria» that can clog plumbing and cause an offensive odor. Over a longer period, the formation of insoluble iron deposits is problematic in many industrial and agricultural applications. To avoid these problems, the U.S. Environmental Protection Agency (EPA) defines the Secondary Maximum Contaminant Level (SMCL) for water treatment and processing plants as 0.3 mg/L Fe in drinking water.The voltammetric determination of the iron triethanolamine complex on the non-toxic Bi drop electrode allows both the detection at very low levels (limit of detection of 0.005 mg/L) and measurements in a wide range of concentrations up to 0.5 mg/L.

Ion chromatography (IC) provides an automated, fast, and sensitive solution to accurately quantify cationic and anionic components including acetate simultaneously. This comprehensive approach makes IC an economic alternative to traditional techniques for the quality control of pharmaceutical solutions like haemodialysis concentrates. Ease-of use, accuracy, and the high-throughput of IC increase productivity and comply with the demands of modern routine and research labs.

Accurate analysis of complexing agents in galvanic baths is possible with inline Raman spectroscopy. This Application Note shows an example using a 2060 Raman Analyzer.

Microbore ion chromatography offers better sensitivity, shorter retention times, and consumes less eluent, increasing sample throughput and reducing running costs.

Scale formation is a critical issue in cooling systems leading to system damage, which generates enormous operational losses. One important component of scale forming is silica. Amorphous silica and metal silicates especially tend to build up scale. Therefore, it is crucial to know the silica concentration in cooling agents. By ion chromatography with UV/VIS detection and PCR, it is possible to determine both free and total silicate content. Sample dilution in ultrapure water and direct injection delivers the free silicate concentration. The total silicate content is determined after hydrolysis of amorphous silica by sample dilution in alkaline eluent, and injection after a reaction time (e.g. 4 hours) prior to the analysis.

Tafel analysis is an important electrochemical technique used to understand reaction kinetics. By studying the Tafel slope, it reveals the rate-determining steps in electrode reactions, aiding fields like corrosion and fuel cell research. This method helps industries optimize processes and improve device performance by tailoring materials and conditions for greater efficiency.

This Process Application Note describes a method to determine the strontium and barium concentration in brine as early detectors ofmembrane fouling via online process ion chromatography. Using this multiparameter analytical technique can help reduce the risk of premature membrane fouling and avoid unexpected maintenance and high utility costs with 24/7 automated analysis.

Bismuth is considered as a metal with a very low toxicity. In high concentrations toxic effects have been described, however. There is no guideline value for bismuth in the World Health Organization’s «Guidelines for Drinking-water Quality» because typical levels usually found in drinking water are of no concern. Anodic stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) for the determination of bismuth in drinking water. While AAS (and competing methods) can only be performed in a laboratory, anodic stripping voltammetry can be used in the laboratory or alternatively in the field with the 946 Portable VA Analyzer. The determination is carried out on the scTRACE Gold electrode.

In power plants, corrosion is the greatest enemy. If corrosive impurities are present in the circuit streams (e.g., chlorides and hydroxides), deposition of an insulating layer of scale on the heat transfer surfaces occurs, resulting in costly and critical downtimes. To ensure high throughput of power plants, online analysis of critical parameters such as sodium is highly advantageous for safety, protection, and process optimization. With the 2035 Process Analyzer from Metrohm Process Analytics, operators gain the information they need to accurately identify trends, reduce downtimes, and address operational issues before costly problems arise.

According to the described method, NTA and EDTA can be determined in mass concentrations of 0.05 mg/L up to 25 mg/L in polluted water and wastewater.At first NTA and EDTA are converted to the corresponding Bi complexes by addition of Bi3+ ions at a pH value of 2.0. As these Bi complexes have significantly different peak potentials, they can be determined simultaneously by DP polarography. The interfering anions nitrite, sulfite, and sulfide are removed from the sample by acidification and purging. Interfering cations are removed by cation exchange; any NTA or EDTA heavy metal complexes present in the sample are disintegrated during this procedure. To remove surfactants and other organic components interfering with the analysis, the sample solution is run through a column filled with non-polar adsorber resin.

In municipal water supplies, higher dissolved oxygen (DO) content is desirable because it improves the taste of drinking water. However, high DO levels also speed up corrosion in water pipes. For this reason, industries utilize water with as little DO as possible, and add scavengers such as sodium sulfite to remove any oxygen from a water supply. Municipal water supply pipes are normally coated inside with polyphosphates to protect the metal from contact with oxygen, thus allowing higher DO contents. Therefore, monitoring the DO content online in a water supply is important to assess its DO content to either improve taste or minimize pipe corrosion. Using an optical sensor, such as the O2-Lumitrode, allows a fast and reliable determination according to ISO 17289.

Monitoring sulfuric acid and zinc sulfate in the viscose wet-spinning process is essential. Online potentiometric titration and colorimetric analysis are recommended for this purpose.

This application note demonstrates EQCM D for simultaneous mass and dissipation analysis of Ni(OH)₂ electrodeposition.

This Application Note details ASTM G61-compliant corrosion measurements performed with VIONIC powered by INTELLO using Metrohm’s ASTM-compliant corrosion cells.

Advances in polymeric membranes and screen-printed technologies have enabled miniaturized, portable potentiometric sensors ideal for point-of-care analysis.

Determination of iron and nickel in binary mixtures by potentiometric titration with EDTA at different pH values using the Cu-ISE.

Nickel can be determined in concentrated zinc solutions by adsorptive stripping voltammetry (AdSV) at the HMDE using ammonia buffer as supporting electrolyte and dimethylglyoxime (DMG) as complexing agent. The determination of cobalt does not work under these conditions as the very high Zn2+ concentration interferes with the Co signal. Therefore, an alternative complexing agent has to be used: α-benzil dioxime in ammonia buffer under addition of sodium nitrite.

The concentration of Co in zinc plant electrolyte (neutral zinc sulfate solution) is determined by adsorptive stripping voltammetry (AdSV) in ammonia buffer with α-furildioxime as complexing agent.

The concentration of Pb in zinc sulfate solution is determined by anodic stripping voltammetry (ASV) in hydrochloric acid electrolyte.

Simultaneous determination of titanium and iron by potentiometric titration with potassium dichromate using a platinum electrode. Before determination, Ti4+ and Fe3+ are reduced with Cr2+.

A potentiometric method for the determination of nickel in gold and silver electroplating baths is described. The titration is carried out with KCN. Gold and silver are removed before titration by a reduction process. It is also possible to determine nickel in steel alloys, etc. (see the literature reference).Ni2+ + 4 KCN + 2NH4+ → (NH4)2[Ni(CN)4] + 4 K+

Two methods are described for the determination of chromium: a biamperometric titration and a polarographic analysis.

The knowledge of the exact silver content of silver allows used for jewelry is very important to ensure the quality of jewelry. Therefore, the determination procedure is regulated internationally and nationally. A common approach is the titration with potassium bromide after an acidic digestion of the silver using a silver electrode for indication.

Zinc, such as that occurring as a constituent of light alloys, can be determined by precipitation titration with potentiometric endpoint indication. The determination of zinc in the presence of cadmium is also possible.2 K4[Fe(CN)6] + 3 ZnCl2 → K2Zn3[Fe(CN)6]2 + 6 KCl

This Application Note looks at the determination of ferrous ion in acidic solutions from approximately 0.25 g/L by thermometric titration with ceric titrant. The exothermic oxidation reaction shows a sharp endpoint that is detected using the Thermoprobe as a sensitive temperature sensor.

A method is described in this Bulletin that allows molybdenum to be determined in steel and other materials containing a high iron concentration. Mo(VI) is determined at the dropping mercury electrode by catalytic polarography. The determination limit is approx. 10 μg/L Mo(VI).

This Application Note describes the fully automated complexometric determination of zinc(II) in aqueous solutions with a copper ion-selective electrode.

A routine method for the determination of copper is described. After dissolving the sample and adding a KI/KCNS solution, the released iodine is back-titrated with thiosulfate. The endpoint indication is potentiometric.

Thallium in aqueous solution can be determined using back titration in a weak acidic solution. The ion-selective copper electrode is used here as the indicator electrode.

Copper can be determined using photometric titration with EDTA at a wavelength of 520 nm.

Determination of Ni, Fe, and Cu in a silver plating bath.

The concentration of total Sb in zinc plant electrolytes is determined by anodic stripping voltammetry (ASV) in 5 mol/L HCl. If 0.6 mol/L HCl is used, only the concentration of antimony(III) is determined selectively. The interference of an excess of Cu is suppressed by the selective oxidation of Cu. Nevertheless, the concentration of Cu in the sample limits the amount of sample that can be used for the determination.

Germanium is determined by adsorptive stripping voltammetry (AdSV) at the HMDE using aqueous sulfuric acid as supporting electrolyte and pyrocatechol violet as complexing agent. It is possible to determine 20 µg/L Ge in a sample containing 150 g/L Zn, 3 g/L Cd and 1 mg/L Pb.

The concentration of Se(IV) in zinc plant electrolyte is determined by cathodic stripping voltammetry (CSV) in ammonium sulfate electrolyte containing EDTA and Cu. The Cu concentration has to be adapted to the sample and the deposition time. With voltammetry only free selenium is determined, therefore it has to be taken into consideration that selenium forms sparingly soluble compounds with numerous cations (e.g. Fe2(SeO3 )3 with Ks = 2·10-31).

The concentration of Te(IV) in Zn plant electrolyte is determined by cathodic stripping voltammetry (CSV) in ammonium sulfate electrolyte containing EDTA and Cu. To get a proper complexation of the interfering Zn a high amount of EDTA is necessary at pH 3.4.

The concentration of As(total) in zinc plant electrolyte is determined by anodic stripping voltammetry (ASV) on a lateral gold electrode in HCl electrolyte. Due to the high excess of zinc in the sample the deposition potential has to be adapted. A second potential approx. 100 mV more negative than the arsenic signal has to be applied to selectively oxidize interfering antimony. For sample preparation the sample was passed through a cation exchange column to reduce the concentration of zinc in the measuring solution.

The concentration of of Sb(III) in zinc plant electrolyte is determined by adsorptive stripping voltammetry (AdSV) with chloranilic acid as complexing agent. In this method high copper concentrations do not interfere. An approx. 10-fold excess of lead interferes, since it shows a signal close to the antimony. With the parameters given below the working range of this method is 1 - 30 µg/L antimony(III) with respect to the concentration in the measuring vessel.

Determination of Fe3+ and Cu2+ in copper refining solutions by thermometric titration. It was found that the conventional approach of masking Fe3+ to permit the iodometric determination of Cu2+ is not possible in some copper refining solutions.

Manganese in aqueous solution can be determined using back titration in alkali solution. The ion-selective copper electrode is used here as the indicator electrode.

Copper, iron, and vanadium can be determined in salt samples in the µg/kg concentration range by adsorptive stripping voltammetry (AdSV) at the HMDE. No sample preparation is necessary.

Determination of nickel in the absence of cobalt and other interferences.

Determination of nickel in solution by titration with standard disodium dimethylglyoximate.

Determination of water in moist particulate solids such as cobalt oxyhydroxide.

Determination of the iron content of iron powder by potentiometric titration with potassium dichromate using the Pt-Titrode.

The exploration and processing of lithium ores is gaining importance with the growing demand for lithium hydroxide. Lithium hydroxide is a key component in the manufacturing of rechargeable batteries for use in various applications including electric vehicles, home storage systems, power tools and consumer electronics. To ensure the efficiency for advanced processing of high purity lithium hydroxide, a fast and reliable quantitative detection technique is required. This application has been developed to monitor the lithium, sodium, and calcium content in the lithium processing samples and mineral concentrates.

This Application Note deals with the determination of ferric ion in acidic and copper-free solutions using thermometric titration. The ferric ion is reduced by iodide. The released iodine reacts exothermically when titrated with thiosulfate solution. The endpoint is determined through temperature plotting by the temperature sensor Thermoprobe.

This Application Note looks at the determination of ferrous ion in acidic solutions through redox titration with potassium permanganate as titrant and thermometric titration.

The total iron content in iron ore plays a central economic role for mining companies. The higher the iron content in the ore, the more profitable the mining operation. Therefore, a fast and accurate analysis is important to determine the most profitable areas to work.The iron ore is dissolved in hydrochloric acid at 80 °C. Afterwards, the iron is quickly and accurately determined by potentiometric titration using the Pt-ring electrode and potassium dichromate as titrant.

Ni and Co are determined in triphosphate by adsorptive stripping voltammetry (AdSV) in ammonia buffer at pH 9.5 with addition of dimethylglyoxime (DMG).

Determination of cuprous ions in the presence of ferrous ions in electrochemical copper leaching solutions.

This poster presents a highly reproducible procedure for the determination of the sodium contribution of acid-extractable organic species in Bayer process liquor. The precision of the method is estimated to be 0.2% RSD.

Determination of Fe3+ by iodometric titration. Useful if Fe3+ is accompanied by Al3+, Mg2+, Ca2+ and Fe2+.