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Capacitors are electronic components necessary for the success of the electronics industry. They have also become essential components of both electric and hybrid vehicles. Electrochemical tests, such as potentiostatic cyclic voltammetry, are used to check the performance of capacitors. VIONIC powered by INTELLO can perform both staircase and linear cyclic voltammetries (CV). This Application Note gives a comparison between the linear and the staircase potentiostatic cyclic voltammetries and highlights the necessity of using the linear CV to best study the performance of capacitors.

This Application Note demonstrates square wave voltammetry for sensitive, reproducible quantification of paracetamol using a screen-printed electrode and INTELLO.

This Bulletin describes the voltammetric determination of aluminum in water samples down to a concentration of 1 μg/L. An aluminum complex is formed with alizarin red S (DASA) and enriched at the HMDE. The following determination employs differential pulse adsorptive stripping voltammetry (DP-AdSV). Disturbing Zn ions are eliminated by addition of CaEDTA.

It is crucial to monitor iodide in NaCl brine to prevent membrane fouling during chlor-alkali electrolysis. Stripping voltammetry offers precise iodide analysis.

This Application Bulletin describes the determination of Sn(II) in presence of Sn(IV) by anodic stripping voltammetry (ASV). Using an electrolyte containing fluoride, Sn(IV) gives no signal, so that a speciation is possible. The limit of detection is 2.5 µg/L.

Nickel and cobalt can be determined in drinking water in one run by adsorptive stripping voltammetry (AdSV). Dimethylglyoxime (DMG) is used as complexing agent at a pH value of 9.3.

This Application Bulletin describes the determination of titanium by adsorptive stripping voltammetry (AdSV) using mandelic acid as complexing agent. The method is suitable for the analysis of ground, drinking, sea, surface and cooling waters, in which the concentration of titanium is of importance. The methods can, of course, also be used for the trace analysis in other matrices.The limit of detection is approx. 0.5 µg/L.

In the past, selenium determinations have always been either unreliable or have required complicated methods. However, as selenium is on the one hand an essential trace element (vegetable and animal tissues contain about 10 μg/kg), while on the other hand it is very toxic (threshold value 0.1 mg/m3), it is very important to cover determinations in the micro range. Cathodic stripping voltammetry (CSV) enables selenium to be determined in mass concentrations down to ρ(Se(IV)) = 0.3 μg/L.

This Bulletin describes the determination of arsenic by anodic stripping voltammetry (ASV) at the rotating gold electrode. A determination limit of 0.5 μg/L can be achieved with 10 mL sample solution. A differentiation between the As(III) concentration and the total arsenic concentration can be made by appropriate selection of the deposition potential. The analyses are performed with a special gold electrode whose active surface is located laterally; c(HCl) = 5 mol/L is used as supporting electrolyte. For the determination of the total arsenic content, As(III) and As(V) are reduced at -1200 mV by nascent hydrogen to As0, which is preconcentrated on the electrode surface. If the deposition is carried out at -200 mV then only As(III) is reduced; this allows the differentiation between total arsenic and As(III). During the subsequent voltammetric determination the preconcentrated As0 is again oxidized to As(III).

The study of the electrochemical behavior of platinum in acidic media is of crucial importance in fundamental electrochemistry and electrocatalysis. Most electrocatalytic processes occurring at Pt electrodes are highly sensitive to the structure of the platinum surface. Cyclic voltammetry (CV) is a widely used rapid measurement technique that provides both a qualitative and quantitative fingerprint of platinum surfaces. A comparison of results given by linear and staircase CVs is presented in this Application Note.

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.

"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."

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.

The method describes the determination of Cr traces in a range between 1 ... 250 μg/L. The method is based on the adsorption of a Cr(lll)-diphenylcarbazonate complex on the Ultra Trace graphite rotating disk electrode (RDE). Organic compounds present in samples (e.g. natural waters) have a strong interfering effect. So they have to be removed by e.g. UV digestion. The determination is made by adsorptive stripping voltammetry in the DC (direct current) measuring mode. Purging with nitrogen is not necessary. The determinations work well also in high salt concentration solutions.

This Application Bulletin describes the methods for the determination of uranium by adsorptive stripping voltammetry (AdSV) according to DIN 38406 part 17. The method is suitable for the analysis of ground, drinking, sea, surface and cooling waters, in which the concentration of uranium is of importance. The methods can, of course, also be used for the trace analysis in other matrices.Uranium is determined as chloranilic acid complex. The limit of detection in samples with low chloride concentration is about 50 ng/L and in seawater about 1 µg/L. Matrices with high chloride content can only be analyzed after reduction of the chloride concentration by means of a sulfate-loaded ion exchanger.

This Application Bulletin describes the determination of cadmium and lead at a mercury film electrode (MFE) by anodic stripping voltammetry (ASV). The mercury film is plated ex situ on a glassy carbon electrode and can be used for up to one day. With a deposition time of 30 s, the limit of detection is ß(Cd2+) = 0.02 µg/L and ß(Pb2+) = 0.05 µg/L. The linear working range for both elements goes up to approx. 50 μg/L using the same deposition time.

Aluminum can be determined in drinking water by adsorptive stripping voltammetry at the HMDE using alizarin red S (DASA) as complexing agent. The method is linear up to 35 μg/L. The detection limit for this method is β(Al) = 1 μg/L, the limit of quantification is β(Al) = 3 μg/L. The sensitivity of the method cannot be increased by deposition.

Cadmium, lead, and copper can be determined simultaneously in oxalate buffer by anodic stripping voltammetry (ASV) after digestion with sulfuric acid and hydrogen peroxide. Tin present in the sample does not interfere with the determination of lead.For the voltammetric determination of tin please refer to Application Bulletin no. 176.

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.

Edible oils and fats contain natural tocopherols and, in some cases, also synthetic tocopherols added as antioxidants. The method described below allows the simple and rapid determination of the tocopherol content by voltammetry. The tocopherols are oxidized electrochemically at the glassy carbon electrode (GCE). The limit of quantitation is approximately 5 ppm (mg/kg) tocopherol.

This Application Bulletin describes the determination of mercury by anodic stripping voltammetry (ASV) at the rotating gold electrode. With a deposition time of 90 s, the calibration curve is linear from 0.4 to 15 μg/L; the limit of quantification is 0.4 μg/L.The method has primarily been drawn up for investigating water samples. After appropriate digestion, the determination of mercury is possible even in samples with a high load of organic substances (wastewater, food and semi-luxuries, biological fluids, pharmaceuticals).

Thiourea forms highly insoluble compounds with mercury. The resulting anodic waves are used for the polarographic determination of thiourea. For the analysis of very small quantities (µg/L), cathodic stripping voltammetry (CSV) is used. Differential Pulse measuring mode is used in both cases.

The standard method postulated by DIN 38406 Part 16 describes the determination of Zn, Cd, Pb, Cu, Tl, Ni, and Co in drinking, ground, surface and precipitation (e.g. rain) water. Because the presence of organic substances in the water samples can strongly interfere with the voltammetric determination, a pretreatment with UV digestion using hydrogen peroxide is necessary. This digestion ensures the elimination of all organic substances without introduction of blank values. These methods can, of course, also be applied for trace analysis in other materials, e.g. trace analysis in the production of semiconductor chips based on silicon. Zn, Cd, Pb, Cu, and Tl are determined on the HMDE by means of anodic stripping voltammetry (ASV), Ni and Co by means of adsorptive stripping voltammetry (AdSV).

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 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 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 Bulletin describes a voltammetric method for the determination of aluminum in water samples, dialysis solutions, sodium chloride solutions and digestion solutions (e.g. of lyophilisates). The method utilizes the complexation of the Al3+ ion by Calcon (Eriochrome blue black R). The formed complex can easily be reduced electrochemically at 60 °C. The limit of quantitation depends on the purity of the reagents used and is approx. 5 µg/L.

A convenient adsorptive cathodic stripping voltammetric (AdCSV) method has been developed for trace determination of uranium(VI) in drinking water samples using chloranilic acid (CAA). The presence of various matrix components (KNO3, Cl-, Cu2+, organics) can impair the determination of the uranium-CAA complex. The interferences can be mitigated, however, by appropriate selection of the voltammetric parameters. While problematic water samples still allow uranium determination in the lower µg/L range, in slightly polluted tap water samples uranium can be determined down to the ng/L range, comparable to the determination by current ICP-MS methods.

This Application Bulletin describes methods for the polarographic and voltammetric determination of small quantities of chromium in water, effluent water and biological samples. Methods for the sample preparation for various matrices are given.

This Application Bulletin describes the voltammetric determination of the elements antimony, bismuth, and copper. The limit of detection for the three elements is 0.5 ... 1 µg/L.

The determination of the lead content in engine fuels has gained considerable importance since the introduction of the catalytic converter technique. Even small contents of lead interfere with the effectiveness of the catalysts or may destroy them. On the other hand, there are still many vehicles on the roads which run on leaded fuel (addition of tetraalkyl lead). Here also the knowledge of the lead content is of interest.With reference to DIN 51769 and ASTM 0-1269 a simplified procedure for the determination of lead in petrochemical products is described. The products are digested with HCl and the lead compounds are converted to lead(II) chloride. After extraction with water, the inverse voltammetric Pb determination is carried out.

This White Paper introduces the principles of cyclic voltammetry (CV) and the various ways it can be used for catalyst investigation. A case study and helpful glossary are provided to support your understanding.

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 TSC SW Closed and TSC Battery cells are compact systems designed for measurements on air or moisture-sensitive materials, such as those used in batteries. In this document, two testing procedures are explained. The first procedure is withpotentiostatic cyclic voltammetry (CV), while the second is via electrochemical impedance spectroscopy (EIS).

This Application Bulletin describes the stripping analysis of Ag at the rotating disk electrode (RDE) with glassy carbon tip (GC) or Ultra Trace graphite tip. In routine operation, the determination limit lies at approx. 10 μg/L Ag, with careful work 5 μg/L Ag can be obtained. After appropriate digestion, silver determination is also possible with samples containing a relatively high proportion of organic substances (e.g. wine, foodstuffs etc.). The method has been developed primarily for water samples (well, ground and wastewater, desilvering solutions of the photographic industry).

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.

The method described allows the determination of W(VI) traces in the range 0.2 to 50 µg/L (ppb). Traces of organic compounds present in the samples (e.g. natural waters) interfere. They have to be removed by UV digestion (e.g. 705 UV Digester). Interference by Fe(III) up to a concentration of 100 mg/L is eliminated by reduction to Fe(lI) with ascorbic acid. If the amount of Cu(II) in the sample exceeds the amount of W(VI) by a factor of 200 or more, the Cu ions have to be bound with thiourea. Moreover, the concentration of Cu(II) should not exceed 5 mg/L. The determination is made by adsorptive stripping analysis in the DP mode.

This Application Bulletin describes …

Cobalt is an essential element for humans because it is a component of vitamin B12. While small overdoses of cobalt compounds are only slightly toxic to humans, larger doses from 25–30 mg per day may lead to skin, lung, and stomach diseases, as well as liver, heart, and kidney damage, and even cancerous growths. The same is valid for nickel, which can lead to inflammation at higher concentrations. Drinking a large amount of water containing nickel can cause discomfort and nausea. In the EU the legislation specifies 0.02 mg/L as the limit value for the nickel concentration in drinking water. This concentration can be reliably determined with the method described in this Application Bulletin.

Convolution voltammetry consists essentially of a voltammetric, chronoamperometric, or chronocoulometric experiment followed by a mathematical transformation - convolution. Using a convolution method, the effect of the decrease of the concentration gradient can be eliminated from the total response of the electrode. This application note explains how the convolution in NOVA works.

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.

Iron is an essential element in the human diet and is found in many natural and treated waters. Therefore, the World Health Organization (WHO) does not issue a health-based guideline value for iron. Higher concentrations of iron in surface waters can indicate the presence of industrial effluents or outflow from other operations and sources of pollution. Because of this, precise, rapid, and accurate iron determination at low concentrations in environmental and industrial samples is of great importance. This can be achieved with the method described in this Application Bulletin.

The iron concentration in boiler feed water has to be monitored to ensure reliable and safe operation of the water-steam circuit. Various guidelines set limits for the maximum iron content.The concentration of total iron in boiler feed water can be determined with high sensitivity using adsorptive stripping voltammetry (AdSV) using 2,3- dihydroxynaphthalene (DHN) as complexing agent. Voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) or inductive couple plasma (ICP) for the determination of iron with only a moderate investment in hardware required and low running costs.

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).

Nickel and cobalt can be determined in seawater by adsorptive stripping voltammetry (AdSV) at the HMDE.

The determination of nickel and cobalt in red wine using adsorptive stripping voltammetry can be carried out after UV digestion of the sample.

Zinc, cadmium, lead, and copper can be determined in red wine after UV digestion by anodic stripping voltammetry (ASV).

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

Cadmium, lead, and copper are determined by anodic stripping voltammetry (ASV) at the HMDE using aqueous nitric acid as supporting electrolyte.

Iron is an essential element in human nutrition. It can be present in drinking water as a result of water treatment or from corrosion in the water piping system. There is no guideline value for iron in the World Health Organization’s «Guidelines for Drinking-water Quality» because typical levels usually found in drinking water are of no concern. However, there are national limit values in various countries. The European Union has set a guideline indicator value for iron of 200 μg/L. Voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) for the determination of iron in drinking water. While AAS (and competing methods) can only be performed in a laboratory, anodic stripping voltammetric determinations can be done used conventionally in the laboratory or alternatively in the field using the with 946 Portable VA Analyzer. The determination is carried out with adsorptive stripping voltammetry (AdSV) using 2,3-dihydroxynaphthalene (DHN) on the scTRACE Gold electrode.

Cr(VI) is determined with the complexant DTPA at pH 6.2 by adsorptive stripping voltammetry (AdSV) at the HMDE.

The concentration of Fe is determined by adsorptive stripping voltammetry at the HMDE with 1-nitroso-2-naphthol (1N2N) as complexing agent.

The concentration of Pb in a Zn phosphatation bath is determined by anodic stripping voltammetry (ASV) in HCl electrolyte.

Iodide contamination in glacial acetic acid poses risks for downstream processes. Cathodic stripping voltammetry (CSV) at the HMDE offers reliable iodide measurement.

The concentration of nickel in ethylene glycol can be determined by adsorptive stripping voltammetry (AdSV) after the organic matrix is destroyed by UV digestion.

The concentration of Ni and Co is determined by adsorptive stripping voltammetry at the HMDE with dimethylglyoxime (DMG) as complexing agent.

Determination of nickel and cobalt in wastewater samples through adsorptive Stripping Voltammetry (AdSV). The wastewater samples first undergo a UV digestion in accordance with DIN 38406 Part 16.

Gold can be determined by anodic stripping voltammetry (ASV) in the µg/l range at the Ultra Trace Graphite electrode. The solution should not contain halide ions.

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.

Germanium can be determined by adsorptive stripping voltammetry (AdSV) at the HMDE using acetate buffer as supporting electrolyte and catechol as complexing agent.

Cd and Pb can be determined in seawater samples in the ng/L concentration range by anodic stripping voltammetry on a mercury film electrode (MFE).

Lead is known to be highly toxic to humans as it interferes with enzyme reactions. Chronic lead poisoning can be caused by lead leaching into drinking water from piping systems. The current provisional guideline value in the World Health Organization’s «Guidelines for Drinking-water Quality» sets a maximum concentration of 10 μg/L. With a limit of detection (LOD) of 0.2 μg/L, anodic stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) to determine lead in drinking water. 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 a silver film applied to the scTRACE Gold electrode.

Electroless Ni plating offers superior surface finish and corrosion resistance. Anodic stripping voltammetry allows Bi stabilizer to be monitored in Ni plating baths.

Platinum in urine can be determined by adsorptive stripping voltammetry (AdSV) after UV digestion of the sample.

For the determination of nickel in white wine, UV digestion is required to mineralize the sample. The determination is done by adsorptive stripping voltammetry (AdSV) at the HMDE in ammonia buffer with dimethylglyoxime (DMG).

Sb is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. The application is carried out with anodic stripping voltammetry (ASV) in hydrochloric acid.

The concentration of Pb in Sn soldering contacts is determined by anodic stripping voltammetry (ASV) in an electrolyte containing citrate, oxalic acid, HCl, and cetyl trimethyl ammonium bromide.

Germanium can be determined by adsorptive stripping voltammetry (AdSV) at the HMDE using acetate buffer as supporting electrolyte and catechol as complexing agent.

Co is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. The application is carried out with adsorptive stripping voltammetry (AdSV) in ammonia buffer with dimethylglyoxime (DMG) as complexing agent.

Anodic stripping voltammetry (ASV) at the HMDE is used to determine manganese in triphosphate. The sample is first digested and then measured in an alkaline solution.

Cd, Pb, and Cu can be determined in one run in acetate buffer by anodic stripping voltammetry (ASV).

Thallium in wastewater is determined in acetate buffer in presence of EDTA by anodic stripping voltammetry (ASV). Samples with organic substances have to undergo UV digestion before analysis.

Rhodium and platinum can be determined in water samples after UV digestion and complexation by adsorptive stripping voltammetry (AdSV) at the HMDE.

The concentration of Cu in seawater is determined by anodic stripping voltammetry (ASV) in acetate buffer on a mercury film electrode (MFE). Gallium is added to overcome zinc interferences.

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.

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.

Zinc, cadmium, lead, and copper can be determined in wastewater samples after UV digestion by anodic stripping voltammetry (ASV) according to DIN 38406 part 16.

Ti is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. Adsorptive stripping voltammetry (AdSV) with mandelic acid as complexing agent is used for this application.

Lead is commonly used as stabilizer in electroless nickel plating processes. The regular and precise determination of the electrochemically active Pb(II) concentration is essential to keep the plating process running optimally under stable conditions. Differential pulse anodic stripping voltammetry can be used to determine the active lead content after dilution. The voltammetric determination has been established as a straightforward, sensitive, selective, and interference-free method for this application.

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

Mercury can be determined in wastewater by anodic stripping voltammetry (ASV) on a gold rotating disk electrode (Au RDE). After the addition of hydrochloric acid and hydrogen peroxide, digestion is done by UV irradiation.

Accurate determination of Fe(II) and Fe(III) in water is crucial for many industries. Cathodic sweeping voltammetry (CSV) offers a robust, cost-effective solution.

The concentration of Fe(total) is determined in wastewater after UV digestion. The method is suitable for iron concentrations down to the low μg/L range. Stripping voltammetry is not applicable for this method. Fe(II) and Fe(III) generate signals with identical sensitivity.

Uranium can be determined in drinking water by adsorptive stripping voltammetry (AdSV) at the hanging mercury drop electrode (HMDE). Chloranilic acid is used as complexing agent.

Higher levels of copper in drinking water are usually caused by corrosive action of water leaching copper from copper pipes. While copper is an essential nutrient for the human organism, ingestion of higher concentrations have an adverse effect on human health. The current World Health Organization’s «Guidelines for Drinking-water Quality» recommend a maximum concentration of 2000 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) for the determination of copper in drinking water. 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.

Arsenic is ubiquitous in the earth’s crust in low concentrations. Elevated levels can be found in mineral deposits and ores. Arsenic from such deposits leaches into the groundwater in the form of arsenite (AsO33–) and arsenate (AsO43–), causing its contamination. As(III) is more toxic than As(V) and shows higher mobility in the environment. The selective determination of this species is possible using the method described in this document.With a limit of detection (LOD) of 0.3 μg/L, anodic stripping voltammetry allows speciation, i.e. the specific determination of As(III). While atomic absorption spectroscopy (AAS) (and competing methods) can only determine the total element concentration, anodic stripping voltammetry is selective to the As(III) oxidation state. The determination is carried out on the scTRACE Gold electrode.

Thiourea is determined by cathodic stripping voltammetry (CSV) at the HMDE in ammonia buffer at pH 8.9. Chloride in the sample does not interfere with this determination.

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.

Monitoring Sb(III) stabilizer levels during electroless Ni plating is critical for high-quality coatings. Anodic stripping voltammetry offers fast, reliable Sb(III) analysis.

Because of its toxicity, the World Health Organization recommends a maximum arsenic content in drinking water of 10 μg/L. Anodic stripping voltammetry with the scTRACE Gold offers a straightforward, highly affordable alternative to spectroscopic determination.

The concentration of Bi in a Sn bath is determined in a HCl / Urotropin® containing electrolyte by anodic stripping voltammetry (ASV). A reaction time of at least 25 min is required before the determination is started. The standard addition solution is also prepared with HCl and Urotropin®.

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.

The concentration of Sb(total) in an acid Cu bath is determined by anodic stripping voltammetry using hydrochloric acid as electrolyte. Due to the excess of Cu the deposition potential has to be chosen only 50 mV more negative than the Sb signal

Zn and Pb are determined by anodic stripping voltammetry (ASV) in acetate buffer at pH 4.6.

The concentration of In in a Sn bath is determined in a HCl / Urotropin® containing electrolyte by anodic stripping voltammetry (ASV). The determination is linear up to approx. 0.5 mg/L with respect to the concentration of In in the measuring vessel. The standard addition solution is also prepared with HCl and Urotropin®.

Arsenic is ubiquitous in the earth’s crust in low concentrations. Elevated levels can be found in mineral deposits and ores. Arsenic from such deposits leaches into the groundwater in the form of arsenite (AsO33–) and arsenate (AsO43–), causing its contamination. In addition to the arsenic originating from natural sources, industry and agriculture contribute to the contamination to a lower extent. The guideline value for inorganic total arsenic in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to 10 μg/L. With a limit of detection (LOD) of 0.9 μg/L, anodic stripping voltammetry is a viable, less sophisticated alternative to atomic absorption spectroscopy (AAS) for the determination of arsenic. 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 using the 946 Portable VA Analyzer. The determination is carried out on the scTRACE Gold electrode.

The presence of copper in fuel ethanol blends has gained considerable attention since Cu2+ catalyzes oxidative reactions in gasoline leading to olefin decomposition and gum formation. Cu2+ in ethanol can easily be determined using anodic stripping voltammetry (ASV) in ethanol/gasoline blends without any sample pretreatment.

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.

This Application Note describes the determination of gallium in electroplating baths used in the production of copper indium gallium diselenide thin-film solar cells (CIGS cells). The CIGS absorber layer is electrodeposited on a molybdenum-coated substrate. Gallium analysis using anodic stripping voltammetry (ASV) is carried out after dilution of the sample with sulfuric acid as supporting electrolyte.

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.

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.

The concentration of Fe(III) is determined by adsorptive stripping voltammetry with solochrome violet RS as complexing agent. All reagents have to be added in the order as listed below. Fe(II) does not show any signal. All reagents typically contain iron impurities. Therefore a subtraction of the reagent blank is recommended.

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.

Iron can be determined in ethanol by adsorptive stripping voltammetry (AdSV) at the HMDE. PIPES buffer is used as supporting electrolyte and catechol as complexing agent at a pH value of 7.0.

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 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 lead and cadmium in polymer materials can be carried out by anodic stripping voltammetry (ASV) using ammonium oxalate buffer pH 2.

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.

The concentration of Sb(III) and Sb(total) in an electroless nickel bath is determined by anodic stripping voltammetry (ASV). In c(HCl) = 0.6 mol/L only Sb(III) shows a signal. In w(HCl) = 10% the Sb(total) content is determined.

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 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).

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).

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.

Voltammetry (VA) is a fast and established method for testing the remaining antioxidant content in industrial lubricants. The flexible and modular Metrohm VA system setup discussed in this White Paper delivers more repeatable and more reproducible results which fulfill all ASTM requirements. Additionally, users can automate the complete analysis process which makes it possible to run series of samples completely unattended.

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 Co in a sulfamate Ni plating bath is determined by adsorptive stripping voltammetry (AdSV) inammonia buffer pH 9.6 with dimethylglyoxime (DMG) as complexing agent. All reagents have to be added in the order listed below. Special care has to be taken that the measuring solution is mixed well before the complexing agent is added. In case of precipitations of Ni-DMG further dilution of the sample is necessary.

Thiomersal (also called thimerosal) is a mercury containing organic molecule that has been widely used as preservative for vaccines and eye drops. It is very effective, even in very low concentrations, against a wide range of microorganisms and viruses. To reduce the risk for consumers the maximum concentration of mercury in the products is limited by the authorities. Polarography or voltammetry can be used to accurately determine the concentration of thiomersal in vaccines or other cosmetic and pharmaceutical solutions (such as eye drops). The method is simple to perform, specific, and free of interferences.

This Application Bulletin describes the determination of inorganic mercury in water samples by anodic stripping voltammetry using the scTRACE Gold sensor. With a deposition time of 90 s, calibration is linear up to a concentration of 30 µg/L; the limit of detection lies at 0.5 µg/L.

Selenium is determined by cathodic stripping voltammetry (CSV) at the hanging mercury drop electrode (HMDE). Se(IV) is deposited on the surface of the mercury drop in sulfuric acid electrolyte under addition of copper ions as Cu xSe y.Wastewater samples containing organic contaminants have to be digested by UV irradiation before analysis. In addition, the sample has to undergo a second irradiation step at pH 7−9 to reduce Se(VI) to Se(IV), since only Se(IV) is electrochemically active.

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.

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.

Presence of thallium in surface water is an indicator of industrial effluents and poses a serious health hazard if imbibed. Monitoring of thallium concentration can easily be done with anodic stripping voltammetry on the silver film modified scTRACE Gold. This non-toxic method allows the determination of thallium concentrations between 10–250 µg/L and can be carried out with the 946 Portable VA Analyzer.

The Se(IV) concentration can be determined by cathodic Stripping Voltammetry (CSV) in an ammonium sulfate electrolyte. The analysis also functions in the presence of Cu. Se(IV) is determined in the first step. In order to register the entire content of Se, Se(VI) species are first reduced to Se(IV). This is handled by the 909 UV Digester at a pH value of between 7 and 9. The method requires practically no reagents and permits selenium speciation.

This Application Bulletin describes the determination of arsenic in water samples by anodic stripping voltammetry using the scTRACE Gold sensor. This method makes it possible to distinguish between As(total) and As(III). With a deposition time of 60 s, the limit of detection for As(total) is 0.9 µg/L, for As(III) it is 0.3 µg/L.

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.

The concentration of Al is determined by adsorptive stripping voltammetry at the HMDE. The method is suitable for Al in concentrations in the range of 0.1 ppb to approx. 40 ppb Al3+. Pb2+ ions do not interfere up to a concentration ratio Pb:Al = 10:1. Due to the slow complex formation of Al with solochrome violet RS the measuring solution was heated to 40 °C for 10 min prior to the determination. For standard addition a solution of Al with solochrome violet RS complex was used. All reagents have to be added in the order as listed below.

The concentration of Fe(total) is determined in monoethylene glycol by adsorptive stripping voltammetry with 2,3-dihydroxy-naphthalene as complexing agent. The detection limit of the method is approx. 0.1 µg/L with respect to the content in the measuring vessel. If no bromate is added to the supporting electrolyte the sensitivity of the method is about 10 times lower. All reagents have to be added in the order as listed below. Fe(II) and Fe(III) give signals with the same sensitivity. All reagents typically contain iron impurities, especially the 2,3-dihydroxy-naphthalene. Therefore a subtraction of the reagent blank is recommended.

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.

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.

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.

No health-based guideline value exists for zinc. However, to maintain good quality municipal drinking water, the United States Environmental Protection Agency (US-EPA) set a maximum concentration of 5 mg/L as the limit value. Typical concentrations in surface and ground waters are between 10–40 μg/L Zn, with values up to 1 mg/L in tap water. Anodic stripping voltammetry (ASV) on the ex-situ mercury film modified glassy carbon electrode provides a less complex alternative to atomic absorption spectroscopy (AAS) for zinc determination in drinking water.

To reduce the toxic effects of cadmium on the kidneys, skeleton, and the respiratory system, as well as the neurotoxic effects of lead, the provisional guideline values in the World Health Organization’s (WHO) «Guidelines for Drinking-water Quality» are set to a maximum concentration of 3 µg/L for cadmium and 10 µg/L for lead.The powerful anodic stripping voltammetry (ASV) technique on the ex-situ mercury film modified glassy carbon electrode is more than sufficient to monitor the proposed WHO guidelines for Cd and Pb in drinking water.

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.

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 Fe is determined in water samples by adsorptive stripping voltammetry with 1-nitroso-2-naphthol as complexing agent. All reagents have to be added in the order as listed below. All reagents typically contain iron impurities. Therefore a subtraction of the reagent blank is recommended. Fe(II) and Fe(III) show different sensitivities. Therefore the sample should only contain one of the iron species. Ascorbic acid (Vitamin C) can be added to the measuring solution and to the Fe(III) standard solution if both Fe(II) and Fe(III) are present in the sample to determine the concentration of total iron. A final concentration of ascorbic acid of 0.002 mol/L is suitable.

The provisional guideline values in the World Health Organization’s (WHO) «Guidelines for Drinking-water Quality» are set to 3 µg/L for cadmium and 10 µg/L for lead. The anodic stripping voltammetry (ASV) technique performed on the ex-situ mercury film modified Metrohm DropSens screen-printed electrode (SPE) can be used to simultaneously detect concentrations as low as 0.3 µg/L for both elements. This is suitable to monitor the WHO guideline values. The main advantage of this method lies in the innovative and cost-effective screen-printed electrode.

The toxic element cadmium (Cd) can be found in elevated concentrations with high bioavailability in some soils. Under such conditions, cacao trees can accumulate cadmium in the beans, which are then processed into cocoa. Chocolate produced from the affected beans will contain elevated cadmium levels. Typical limit values in the European Union are between 100 µg/kg and 800 µg/kg (EU Commission Regulation 1881/2006) depending on the cocoa content of the chocolate.Anodic stripping voltammetry (ASV) can be used to accurately determine trace quantities of cadmium in chocolate down to approximately 10 µg/kg. The method is simple to perform, specific, and free of interferences. Prior to determination the samples are ashed in a furnace at 450 °C.

The toxicity of antimony depends on its oxidation state: antimony(III) is more toxic than antimony(V). Due to its carcinogenicity, EU legislation specifies 5 µg/L and the World Health Organization (WHO) sets a maximum concentration of 20 µg/L as the Sb(III) limit value in drinking water.Straightforward determination using anodic stripping voltammetry provides a fast (analysis time under 10 minutes) and an ultra-sensitive tool for monitoring the antimony(III) concentration in drinking water. Measurements can be performed in the laboratory with the 884 Professional VA, or alternatively in the field with the 946 Portable VA Analyzer.

Electroless nickel plating is an important and well established process in the surface finishing industry. In the past the addition of small amounts of lead has widely been used to stabilize the plating bath. With the increasing number of restrictions in recent years on the use of lead in consumber products, particularly electronics, alternative stabilizers were developed and introduced. Two of the stabilizers used as lead replacement are antimony and bismuth. They can be used as a single additive or in combination with each other or iodate. This method allows the determination of antimony and bismuth directly in the plating bath sample by anodic stripping voltammetry (ASV). The method is simple and fast, however sensitive and robust

EU legislation specifies 20 µg/L as the limit value for nickel in drinking water. The current provisional guideline value for Ni in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to a maximum concentration of 70 µg/L. The adsorptive stripping voltammetry (AdSV) technique performed on the ex-situ bismuth film modified Metrohm DropSens 11L screen-printed electrode (SPE) can be used to simultaneously detect concentrations as low as 0.4 µg/L for nickel and 0.2 µg/L for cobalt with a 30 s deposition time.The disposable, maintenance-free sensor can be used conventionally in the laboratory with the 884 Professional VA, or alternatively in the field with the 946 Portable VA Analyzer. This method is best suited for manual systems.

The guideline value for chromium in the World Health Organization’s (WHO) «Guidelines for Drinking-water Quality» is 50 µg/L. It should be noted here that chromium concentrations are often expressed as total chromium and not as chromium(III) or (VI). Chromium(VI) is responsible for changes in genetic material, and is found in significantly lower concentrations than Cr(III). Therefore an extremely sensitive method is required to monitor Cr(VI) in drinking water.The powerful adsorptive stripping voltammetry (AdSV) technique on the ex-situ mercury film modified glassy carbon electrode using DTPA as complexing agent can be used to determine such low concentrations.

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.

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.

Tellurium is one of the elements recently identified as technologically critical for photovoltaic conversion, quantum dots, as well as in thermoelectric technology, and has the potential to become a new emergent contaminant. Until now there is no guideline value in the World Health Organization’s «Guidelines for Drinking-water Quality» and in the European Drinking Water Directive for tellurium(IV) concentration in drinking water.To monitor the tellurium(IV) levels in drinking water, anodic stripping voltammetry (ASV) performed on the unmodified scTRACE Gold is recommended. This method allows determination of tellurium(IV) in the concentration range between 1 µg/L and 60 µg/L when using a 90 s deposition time. The scTRACE Gold electrode does not need extensive maintenance such as mechanical polishing. Measurements can be performed in the laboratory with the 884 Professional VA or alternatively in the field with the 946 Portable VA Analyzer.

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.

Zinc is an essential trace element for humans. Excessive intake of zinc in higher concentrations can be harmful, however. There is no guideline value for zinc 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 zinc in drinking water. While AAS (and competing methods) can only be performed in a laboratory, anodic stripping voltammetric determinations can be used conventionally in the laboratory or alternatively in the field using with 946 Portable VA Analyzer. The determination is carried out on the scTRACE Gold electrode.

In addition to its natural occurrence in fruit and vegetables, ascorbic acid (Vitamin C) is used as an antioxidant in foods and drinks. Ascorbic acid is furthermore also to be found in numerous drugs.Ascorbic acid and its salts and esters can be determined with titration or by using polarography, for which ascorbic acid is oxidized to form dehydroascorbic acid.Bi-voltammetric or photometric equivalence point indication can be used for titrimetric determination. It must be taken into account here that only bi-voltammetric indication is independent of the inherent color of the sample. Polarography is the most selective of the methods described, as other reducing or oxidizing substances are not recorded.

Thiourea measurement during copper electrorefining can be complicated by high chloride levels. Voltammetric analysis overcomes this issue, improving copper quality.

Testing of in-service lubricating oils for their remaining antioxidant content is critical for capital equipment uptime as well as reducing running costs and repair expenses. Test methodologies such as RPVOT (rotating pressure vessel oxidation test) are time consuming and expensive to perform. Remaining Useful Life is a proven voltammetric method for testing the remaining active antioxidant content in minutes. Depending on the electrolyte, aromatic amine and phenolic antioxidants or hindered phenolic antioxidants can be determined.For the first time, a fully automated system is demonstrated, showing dramatically improved repeatability of data for confidence in reporting. Operator time is saved during sample preparation and irreproducible manual interpretation is eliminated via completely autonomous software processing. The user adds the sample into the vials, then the determination process of the sample series (including sample preparation and result calculations) is carried out automatically. The system is based on methods ASTM D6810, ASTM D6971, ASTM D7527, and ASTM D7590.

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 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.

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 difference between the toxic and essential levels of selenium to human health are very slight. Therefore, the current provisional guideline value for selenium(IV) in the World Health Organization’s «Guidelines for Drinking-water Quality» and in the European Drinking Water Directive is set to a maximum concentration of 10 µg/L.The anodic stripping voltammetric (ASV) technique performed on the unmodified scTRACE Gold can be used to determine concentrations as low as 0.5 µg/L selenium with a 30 s deposition time. These limits can be lowered even further by increasing the deposition time. The linear range at 30 s deposition time ends at approximately 100 μg/L. The scTRACE Gold electrode does not need extensive maintenance such as mechanical polishing. Measurements can be performed in the laboratory with the 884 Professional VA or alternatively in the field with the 946 Portable VA Analyzer. This method is suited for manual or automated systems.

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.

Voltammetric determination of boron in plasma using Beryllon III as a ligand [L. Thunus (1996), Anal. Chim. Acta 318: 303–308].

Determination of suppressor «Solderon ST-200 Primary» in a tin bath by dilution titration (DT) using cyclic voltammetric stripping (CVS).

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.

Determination of suppressor «Ronastan TP Additive» in a tin/lead bath by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of suppressor «Cupraspeed» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of suppressor «InPulse H6» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Electrochemical methods provide an alternative to traditional methods used to determine the rate of corrosion. For example, corrosion rates, the rates at which a specimen corrodes, can be calculated from simple electrochemical measurements like a linear sweep voltammetry (LSV).

Determination of suppressor «Cupracid BL-CT» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of brightener «Cupraspeed» in acid copper baths by modified linear approximation technique (MLAT)using cyclic voltammetric stripping (CVS).

Determination of suppressor «Copper GleamTM 2001 Carrier» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of suppressor «MACuSpecTM PPR 100 Wetter» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of suppressor «Thru-Cup EVF-B» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of suppressor «Top Lucina α-M» in acid copper baths by dilution titration (DT) using cyclic voltammetric stripping (CVS).

Determination of leveler «Top Lucina α-3» in acid copper baths by response curve technique (RC) using cyclic voltammetric stripping (CVS).

Determination of brightener «InPulse H6» in acid copper baths by modified linear approximation technique (MLAT) using cyclic pulse voltammetric stripping (CPVS).

Determination of brightener «Thru-Cup EVF-1A» in acid copper baths by modified linear approximation technique (MLAT) using cyclic voltammetric stripping (CVS).

Determination of leveler «Thru-Cup EVF-R» in acid copper baths by response curve technique (RC) using cyclic voltammetric stripping (CVS).

Determination of brightener «Top Lucina α-2» in acid copper baths by modified linear approximation technique (MLAT) using cyclic voltammetric stripping (CVS).

In this Application Note, the electrochemical properties of electrodes with a micrometer-size surface area are compared with the electrochemical properties of electrodes with millimeter-size surface area. The comparison is made through cyclic voltammetry in a Fe3+/Fe2+ (ferro/ferri) solution, and the differences in the voltammograms are explained with the different diffusion profiles at the electrode-electrolyte interface.

Determination of brightener «Copper GleamTM 2001 Additive» in acid copper baths by modified linear approximation technique (MLAT) using cyclic voltammetric stripping (CVS).

Determination of brightener «MACuSpecTM PPR 100 Brightener» in acid copper baths by modified linear approximation technique (MLAT) using cyclic voltammetric stripping (CVS).

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.

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.

This Application Note highlights the use of Metrohm Hyphenated EC-Raman Solutions to monitor the reversible oxidation of ferrocyanide at a gold electrode.

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

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.

Many different configurations are made possible when using two-, three-, or four-electrode cell setups in research. Depending on the experimental requirements, one setup may be preferred over another. Therefore, the proper electrode arrangements for these three situations are defined in this Application Note. As an example, the potential at the counter electrode is measured during the platinum oxidation in acidic media, with the second sense (S2) of VIONIC powered by INTELLO. Since dissolved Pt in solution could bias the results, it is important to be able to monitor the potential of the counter electrode.

By combining the information from electrochemical and spectroscopic techniques, UV/VIS spectroelectrochemistry (UV/VIS-SEC) allows a comprehensive analysis of electron-transfer processes and complex redox reactions. The anodic oxidation of a N-aryl-D2-pyrazoline derivative was investigated by combining cyclic voltammetry and UV/VIS spectroscopy. In-situ measured UV/VIS absorbance depicted the absorption changes that accompanied the anodic oxidation and could therewith prove the stability of the electrogenerated radical cation. UV/VIS-SEC provides a powerful tool for the in situ study of shorter-lived species, reaction mechanims, and kinetics in a wide variety of electrochemical active organic, inorganic, and biological molecules.

The guideline value for total chromium in the World Health Organization’s (WHO) «Guidelines for Drinking-water Quality» is 50 µg/L. Chromium(VI) is more toxic than its trivalent form (Cr(III)) and is also less abundant. Therefore a robust and sensitive method is required to monitor its concentration in drinking water. The mercury film modified scTRACE Gold can be used to monitor chromium(VI), offering easy handling and a high grade of stability.

Due to the toxicity and the detrimental effects of nickel and cobalt on human health, their concentrations in drinking water must be controlled. Therefore, EU the legislation specifies 20 µg/L as the limit value for nickel in drinking water. The current provisional guideline value for Ni in the World Health Organization’s «Guidelines for Drinking-water Quality» is set to a maximum concentration of 70 µg/L. To monitor the concentrations of Ni and Co with the 884 Professional VA, a method for simultaneous determination on the glassy carbon electrode (GC-RDE) modified with a Bi film is used.

For the past three decades, Cyclic Voltammetric Stripping (CVS) has been the standard practice for analyzing organic additives in electroplating copper baths in the circuit board and wafer plating industries. The variations in the compositions of such baths have created a need for more optimized method development routines. New advancements in the hardware and software protocols for CVS have simplified the overall process of method optimization to a great extent. In this study, the process of method optimization is discussed in conjunction with these protocols.

Benzbromaron is one of the main uricosuric drugs currently used. In addition to sophisticated and expensive LC-MS and GC-MS methods, benzbromaron can be effectively determined by titration with sodium hydroxide solution using a straightforward, fully automated sample preparation method. A high-frequency homogenizer comminutes one or three tablets within 90 or 120 s respectively. The overall analysis time is 8 minutes. Ten-fold determinations with one and three tablets resulted in a benzbromaron content of 99.2 and 98.7 mg per tablet respectively. Increasing the number of tablets from one to three lowers the RSD from 1.36 to 0.88%. These results show an excellent agreement with the benzbromaron content indicated by the manufacturer (approx. 100 mg/tablet).Besides the presented Titrando/homogenizer combination, the other two members of the 815 Robotic Soliprep Sample Processor family offer comprehensive sample preparation possibilities within the fields of IC, HPLC, ICP or voltammetry.

Determination of ß-propiolactone in vaccine.

Determination of cysteine and cystine in an infusion solution.

NTA and EDTA can be determined as their bismuth complexes at the DME.

This polarographic method uses the Multi-Mode Electrode Pro for simultaneous detection of carbonyl impurities in alcohols, ensuring high product quality and stability.

This Application Bulletin describes a simple polarographic method to determine monomeric styrene in polymers. The limit of determination lies at 5 mg/L. Before the determination, styrene is converted to the electrochemically active pseudonitrosite using sodium nitrite.

Quinine can be determined by polarography at the DME using Britton-Robinson buffer at pH = 7.0 as supporting electrolyte.

Cinchocaine (dibucaine) is used in the form of ointments or injection solutions as a local anaesthetic. Its base is soluble in diethyl ether; its hydrochloride, on the other hand, is insoluble in diethyl ether but easily soluble in water. This Bulletin describes the determination of cinchocaine in ointments, creams and injection solutions by means of differential pulse polarography. An acetate buffer pH = 4.8 is used as the supporting electrolyte. The limit of quantitation and the linear working range of the method are given. The necessary sample preparation steps are also dealt with in this Bulletin.

Determination of styrene monomers in polystyrene. Free styrene is converted to a polarographically active pseudonitrosite.

Total chromium can be determined in wastewater samples. UV digestion is necessary to remove interfering organic matter before the analysis. Complete oxidation of Cr(III) to Cr(VI) is guaranteed by an additional UV irradiation step at pH > 4.

Cr(VI) is determined by polarography at the SMDE in acetate solution containing ethylene diamine to mask interfering copper ions.Only Cr(VI) is electrochemically active. It is for that reason that all chromium compounds must be present before the analysis as CR(VI), which is guaranteed by UV radiation with a pH > 4.

Iron sucrose injection is a dark brown liquid which contains sucrose and iron(III) hydroxide in an aqueous solution, commonly used for the treatment of iron deficiency anemia. As a medical product, iron sucrose is subject to strict controls. Among other tests, the U.S. Pharmacopeia (USP) requires to monitor the limit of Fe(II) in the iron sucrose injection solution by polarography. The benefit of polarography is that Fe(II) and Fe(III) show signals at different potentials, and therefore an easier determination of Fe(II) without a previous separation of the two oxidation states is possible. The 884 Professional VA together with the viva software allows a straightforward determination of the Fe(II) content of iron sucrose injection solution following the requirements of the USP. The Fe(II) content is automatically calculated and stored in a database together with all relevant determination and calculation parameters.

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.

Lithium iron phosphate batteries offer users safety and durability. Polarographic speciation evaluates Fe(II) and Fe(III) in cathode material, useful for several tests.

Determination of Al in alkaline ZnO solution with Eriochrome Blue Black R at 60 °C.