Application Finder

Water treatment with ozone (O3) is a common procedure for the disinfection of swimming pools. It is important that a sufficient but not excessive amount of O3 is produced to disinfect the water. Otherwise, the remaining ozone could enter the swimming water, which could irritate the respiratory system or the skin of bathers.Ozone is also used in drinking and waste water treatment because it is significantly more effective than chlorine at inactivating or killing viruses and bacteria. This application note describes a method to determine the ozone concentration in water by potentiometric titration according to DIN 38408-3.

Learn about PFAS, their impact on water quality, EU Directive 2020/2184, and the benefits of AOF measurement using combustion ion chromatography (CIC).

Bromide is ubiquitous in sea water, where it is present in concentrations of around 65 mg/L. By contrast, the maximum bromide concentration in drinking and ground water is usually less than 0.5 mg/L. A higher bromide content may indicate a contamination of the water caused by fertilizer, road salt or industrial waste water. This Application Note describes the determination of the bromide content in water via direct measurement with a Br ion-selective electrode in accordance with ASTM D1246.

Determination of perchlorate in water containing 3 g/L of total dissolved solids (TDS) using anion chromatography with conductivity detection after chemical suppression.

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.

Ion chromatography (IC) is the method of choice to determine the concentration of common ions in water. This information is crucial as drinking water must meet certain standards to guarantee health (e.g., nitrite and nitrate), as well as technical suitability (e.g., corrosiveness of chloride and sulfate). The Eco IC is an ion chromatograph suitable for economical routine water analysis. Using an A Supp 17 anion column, the analysis of major anions in drinking waters is robust and can be performed at ambient temperatures without additional temperature conditioning.

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.

The permanganate index (PMI) is a sum parameter that indicates the total load of oxidizable organic and inorganic matter in water. The substances concerned are mainly humic materials/acids that are primarily formed when dead organic material present in soil is further broken down and released into water sources. As it is an indicator of the water quality, testing of the PMI for drinking water is obligatory in many countries.For the determination, it is necessary to heat the stabilized water sample to 95 °C and higher for a stipulated time. Afterwards, the amount of permanganate that has remained after the reaction with the sample is determined titrimetrically. This sample preparation step requires considerable manual effort.In this Application Note, a fully automated procedure for the determination of the PMI according to GB/T 11892 is described, including all sample preparation steps. The gains in productivity because of a reduced manual workload are considerable.

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.

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.

A complete tap water analysis includes the determination of the pH value, the alkalinity and the total water hardness. Both the pH measurement and the pH titration by means of a standard pH electrode suffer from several drawbacks. First, the response time of several minutes is too long and, above all, the stirring rate significantly influences the measured pH value. Unlike these standard pH electrodes, the Aquatrode Plus with its special glass membrane guarantees rapid, correct and very precise pH measurements and pH titrations in solutions that have a low ionic strength or are weakly buffered. Total water hardness is ideally determined by a calcium ion-selective electrode (Ca ISE). In a complexometric titration, calcium and magnesium can be simultaneously determined up to a calcium/magnesium ratio of 10:1. Detection limits for both ions are in the range of 0.01 mmol/L.

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.

Water of the water-steam cycle of boiling water reactors (BWR) needs to be free of corrosive anions. Analyzing these trace anions allows the parallel determination of chromate, which is a potential corrosion product. Automated sample preparation includes variable Inline Preconcentration (MiPCT) and automatic calibration with a single multi-ion calibration standard.

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.

Oxygen diffuses into water sources from the air via aeration, however several factors can reduce the dissolved oxygen (DO) content in water. First, as water warms up, oxygen is released into the atmosphere. Secondly, oxygen is consumed by bacteria and other microorganisms which feed on organic material. Finally, plants can also consume oxygen in certain situations.Human-induced alterations can have a negative influence on surface water when DO values fall below crucial limits for maintaining the life supporting capacity of freshwater ecosystems. Therefore, monitoring the DO content in surface water by an optical sensor to assess its quality is important.

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.

Even in low concentration, sulfide ions cause odor and corrosion problems in ground water and waste water. They can release hydrogen sulfide in acidified water, which is toxic in even minuscule amounts. This Application Note describes the determination of sulfide concentration in water via direct measurement with the Ag/S-ISE in accordance with ASTM D4658.

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.

During drinking water disinfection with chlorine, chloramine, or ozone, potentially toxic halogenated byproducts can be formed. The disinfectants can react with naturally occurring bromide and/or organic matter in the source water and form one of the most common and highly toxic disinfection byproducts (DBPs): haloacetic acids (HAAs). To protect human health, maximum tolerable levels of HAA in drinking waters are regulated (EPA 816-F-09-004). The EPA Method 557 specifies the analysis of HAAs beside bromate and dalapon by ion chromatography coupled to tandem mass spectroscopy (IC-MS/MS) with LODs varying from 0.02–0.11 µg/L. However, even with single MS, a high sensitivity is achieved to determine the current MCLs within an adequate accuracy. This Application Note describes the analysis of bromate, chlorite, monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), bromochloroacetic acid (BCAA), bromodichloroacetic acid (BDCAA), dibromoacetic acid (DBAA), dichloroacetic acid (DCAA), tribromoacetic acid (TBAA), chlorodibromoacetic acid (CDBAA), and trichloroacetic acid (TCAA) with IC/MS. The Metrohm Driver 2.1 for EmpowerTM offers the analysis as a single software solution with EmpowerTM.

Determination of silica (as silicate) in pure water with preconcentration using anion chromatography with direct conductivity detection (without any post-column reaction).

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.

In pressurized water reactors (PWRs), light water is used as primary coolant. Boron (as boric acid) readily absorbs neutrons and is added to the coolant to control reactivity. Lithium hydroxide assures a pH value greater than 7 to prevent corrosion. This application allows to measure sub-ppb levels of zinc, nickel, calcium, and magnesium besides high boric acid and lithium hydroxide concentrations.

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.

Water of the primary cycle of pressurized water reactors (PWR) contains boron for neutron absorption. The high borate content interferes with the direct analysis of trace anions. Inline Neutralization combined with variable preconcentration and Inline Matrix Elimination (MiPCT-ME) allows to remove boron as boric acid before injection.

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.

ASTM D8192 describes the photometric titration of the total hardness, calcium hardness, and magnesium hardness in water with an optical sensor for objective endpoint indication, increasing precision and reliability. The method is suitable for both colored and colorless samples such as groundwater, surface water, wastewater, and drinking water. Using a fully automated OMNIS system equipped with an Optrode ensures that the sample preparation and analysis are repeatable.

The ASTM D8192 standard allows analysts to determine water hardness in different water matrices by complexometry with automated photometric endpoint recognition, increasing the reproducibility and the precision of the results.

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.

Chromate and dichromate are the two oxoanions of chromium. In both, chromium is present in its hexavalent form (Cr(VI)). In aqueous solutions, chromate exists under alkaline and dichromate under acidic conditions. Hexavalent chromium is highly toxic and carcinogenic. It is therefore restricted in manufactured goods as well as in the environment and requires thorough monitoring. DIN 38405-52 describes the determination of Cr(VI) in water, wastewater, and sludge by photometric methods. In Appendix C, chapter C.6 the use of ion chromatography is described. This AN shows the application of the method to drinking water samples.

Water chemistry of the water-steam cycle is crucial for maintaining plant reliability and for ensuring optimal plant operational conditions. Impurities such as corrosion products in ionic, colloidal, or oxide forms are ubiquitous in feedwater, condensate, and reactor coolant. This application shows the determination of sub-ppb levels of Cu, Ni, Zn and standard cations (e.g., Na+, NH4+, Mg2+, Ca2+) in the water-steam cycle of a BWR.

Determination of perchlorate in process water using anion chromatography with direct conductivity detection.

Determination of silicate in tap water using anion chromatography with direct conductivity detection.

Perchlorate is a wide-spread contaminant in drinking water. In addition to a few natural sources, perchlorate is generally released into drinking water from propellants and from disinfecting and bleaching agents. Convenient separation from other ions is accomplished on a column of the Metrosep A Supp 7 - 250/4.0 type before it is quantified using sequential suppression and conductivity detection. In comparison to AN-S-324, this Application Note shows a considerably lower matrix influence.

Determination of bromate in mineral water using anion chromatography with conductivity detection after chemical suppression.

The determination of the physical and chemical parameters as electrical conductivity, pH value, alkalinity, the calcium and magnesium hardness as well as the total hardness are necessary for evaluating the water quality. A fast and accurate determination in tap water is realized using an automated OMNIS System working in parallel on different workstations. An 856 Conductivity Module with Dosinos extends the system.

Determination of chloride in water by direct potentiometry using the Cl-ISE.

Monitor adsorbable organic halogens (AOX) in water using combustion ion chromatography (CIC) for precise analysis of AOCl, AOBr, AOI, and total AOX.

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.

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.

Water hardness is often determined photometrically using two different indicators and while performing the determination at two different pH values. Additionally, the determination itself is subjective, as the color change is determined by the analyst and not by an analytical device.This application note introduces a more robust option to easily assess calcium, magnesium, and total hardness in water by using the Cu-ISE and two different titrants. Sample preparation is identical for both analyses and can therefore be automated without any issues.

This Application Note presents a potentiometric titration method for trace H2S analysis in water on an OMNIS system using silver nitrate and an Ag Titrode.

The water content of ointments is determined according to Karl Fischer. Because of their high water and fat content, the samples are prediluted with a 1:1 mixture of chloroform and methanol.

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.

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.

Cyanides are used in some industrial processes, but if not handled carefully, they could contaminate the wastewater. In an acidic or neutral environment, this contaminated wastewater can form highly toxic hydrogen cyanide gas. Furthermore, the cyanide salts could also poison the environment and enter the ground water system. Therefore, it is essential to monitor the content of cyanide in effluent water. Cyanides can be easily determined with a cyanide ion-selective electrode. This application note presents a method for cyanide analysis according to APHA Method 4500-CN and ASTM D2036.

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.

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.

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.

Thermal power plants require enormous amounts of water, using high purity steam at high pressure to rotate turbines. A separate cooling water circuit is implemented, which helps to form a vacuum when the steam condenses after the turbines. Maintaining this vacuum with optimal condensation parameters is critical for the power plant efficiency. The copper condensers are susceptible to corrosion by ammonia, leading to an upper limit of 2 mg/L NH3 set by EPRI in cooling water. Small cracks in the condenser combined with the large pressure differential between the steam circuit and the cooling water circuit will contaminate the high purity water in the boiler, causing major problems and necessitating a shutdown for plant maintenance. Monitoring NH3 online in cooling water with a process analyzer can signal early problems in a plant before significant intermediation is necessary.

For the first time, glyphosate determination and that of its primary metabolite AMPA in drinking water using IC with pulsed amperometric detection (flexIPAD) in the low µg/L range are shown. Compared to HPLC analysis with a mass-selective detector, it is a very cost-effective method for determining the glyphosate and AMPA content in water and foodstuffs. With a detection limit at approx. 1 µg/L, compliance with limit values for glyphosate can be monitored in the USA, Canada, and Australia, among others.

Determination of lithium, sodium, potassium, calcium, and magnesium in tap water using cation chromatography with direct conductivity detection.

Determination of hypophosphite, phosphite, and phosphate in the presence of fluoride, chloride, and sulfate in process water using anion chromatography with suppressed conductivity detection.

Determination of citrate in mineral water drinks by potentiometric titration with copper sulfate using the Cu-ISE. Before the determination, the sample is degassed and passed through a cation-exchange resin.

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 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.

Determination of chlorite and chlorate in tap water using anion chromatography with conductivity detection after chemical suppression.

Fast and reliable analysis of drinking water by combining EPA method 300.1 Parts A and B in a single IC run.

Nitrate is naturally present in the environment. However, excessive concentrations of nitrate in surface and ground water are problematic as such concentrations have a negative effect on the water quality. Usually, excessive levels of nitrate area direct result of extensive usage of fertilizers in agriculture. Nitrate is easily washed from soils and can end up in surface or ground water. As the nitrate content is regulated in many countries, a quick and inexpensive assessment of its concentration is required to monitor the water quality.The nitrate concentration can easily be obtained by direct measurement using a nitrate ion selective electrode. First, a calibration is performed, afterwards, the samples are measured in less than a minute.This is a fast, inexpensive and reliable method to determine the nitrate content in various water samples.

The water content of coal dust is determined according to Karl Fischer. Because of the low water content of the voluminous sample, the oven method (nitrogen, 270 °C) and coulometric titration have to be used.

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.

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 water content of plastic chips is determined according to Karl Fischer. Because of the low water content of the sample, the oven method (200 °C) and coulometric titration have to be used.

The water content of yoghurt powder is determined according to Karl Fischer. Because of the relatively high water and fat content, the sample is prediluted with a 1:1 mixture of chloroform and methanol.

Determination of 2-fluorobenzoate in a water deposit from the oil production industry using anion chromatography with conductivity detection and chemical suppression.

Fluoride content in drinking water can be determined quickly and conveniently with the help of potentiometric titration and the ion-selective fluoride electrode (F-ISE). The F-ISE is calibrated with suitable standard solutions before the measurement.

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.

The determination of the physical and chemical parameters as electrical conductivity, pH value, p and m value (alkalinity), chloride content, the calcium and magnesium hardness, the total hardness, as well as fluoride content are necessary for evaluating the water quality. This bulletin describes how to determine the above mentioned parameters in a single analytical run.Further important parameters in water analysis are the permanganate index (PMI) and the chemical oxygen deman (COD). Therefore, this Bulletin additionally describes the fully automated determination of the PMI according to EN ISO 8467 as well as the determination of the COD according to DIN 38409-44.

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

The Metrosep A Supp 21 column and 948 Continuous IC Module, CEP enable efficient, automated single-run analysis of major anions and disinfection byproducts in water.

Determination of arsenite and arsenate in process water using ion-exclusion chromatography with UV detection.

Determination of the water content of liquid ammonia according to Karl Fischer after absorption of the water in ethylene glycol.

The water content of turbine oil is determined according to Karl Fischer. Because of the low water content of the sample, coulometric titration is used.

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.

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 presence of excessive water in plastics adversely affects the performance of polymeric goods which is why water determination is of crucial importance. This article describes the accurate and straightforward determination of the water content using the Karl Fischer Oven Method in ten different plastic types that are not amenable to direct Karl Fischer titration. The experiments revealed that besides the determination of the oven temperature, sample preparation is one of the most important steps of the analysis, especially in case of hygroscopic plastic samples.

Determination of chloride, nitrate, and sulfate in produced water using anion chromatography with conductivity detection after chemical suppression.

Determination of ammonia (ammonium) in distilled water by direct potentiometry using the NH3-ISE.

Potassium is naturally occurring in surface water caused by weathering of stones and soil. As potassium in drinking water is regulated and should not exceed a certain threshold value, it is necessary to assess the potassium concentration.This can easily be done by direct measurement using a potassium selective electrode. First, a calibration is performed, afterwards, the samples are measured within tens of seconds. This is a fast, inexpensive and reliable method to determine the potassium content in various water samples.

Determination of carbonate in tap water using ion-exclusion chromatography with suppressed conductivity detection.

Determination of boric acid and acetic acid in process water using ion-exclusion chromatography with conductivity detection after chemical suppression.

The water content in panthenol is determined according to Karl Fischer.

Determination of carbonate in sparkling water using ion-exclusion chromatography with suppressed conductivity detection.

Determination of water content in ink is possible with Karl Fischer titration, as shown in this Application Note.

The water content of margarine is determined according to Karl Fischer.

The water content of spices is determined according to Karl Fischer. To release the water from the cells, a high-frequency homogenizer has to be used.

Perchlorate is a wide-spread contaminant in drinking water. Apart from a few natural sources, it usually comes from disinfectants and bleaches as well as rocket fuel. Perchlorate is detected after separation on the Metrosep A Supp 7 - 250/4.0 column using sequential suppression and conductivity detection.

The water content in methylcyclohexane is determined by coulometric Karl Fischer titration.

Determination of phenol, m-cresol, 2,6-dimethylphenol and 2,3,6-trimethylphenol in tap water with amperometric detection using a glassy carbon electrode.

Determination of phenol, m-cresol, 2,6-dimethylphenol, and 2,3,6-trimethylphenol in tap water using amperometric detection and a glassy carbon electrode.

For a variety of reasons, the water content of chocolate is of crucial importance and has to be accurately determined. This poster compares an automated version of the Karl Fischer titration (KFT) using the sequential addition of various solvents with the widespread manual titration at elevated temperatures using a chloroform/methanol mixture. The water contents determined by the two procedures show excellent agreement. However, manual titration requires laborintensive sample preparation, the side reactions are difficult to quantify and hazardous halogenated solvents have to be used. In contrast, automated KFT is straightforward, uses non-hazardous solvents, allows to quantify the side reactions and is easily applicable to water determinations in sugar- and fat-containing matrices.

The water content of moisturising creams is determined according to Karl Fischer. Because of their high water content, the samples are first mixed and prediluted with dry methanol.

The microbore Metrosep A Supp 4 - 250/2.0 column is particularly suitable for the analysis of anions in critical samples. A waste water sample is being analyzed in the current application. The sample requires only one filtration prior to injection on the Metrosep A Supp 4 - 250/2.0. The anions are quantified with the application of conductivity detection following sequential suppression.

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.

Determination of the anions in potable water using anion chromatography with conductivity detection after chemical suppression.

Alkalinity defines the acid-binding capacity of natural water. A distinction is made between total alkalinity (m-value) and carbonate alkalinity (p-value). This Application Note presents the determination of pH and alkalinity in water with a titration method conforming to EPA 310.1, Standard Methods 2320 B (Titration Method), ASTM D1067, EN ISO 9963-1, and EN ISO 9963-2.

Determination of nitrite in mineral water using anion chromatography with UV detection.

Determination of the method detection limit (MDL) and method quantification limit (MQL) of bromate in drinking water using anion chromatography with conductivity detection after chemical suppression.

Moisture in petroleum products causes several issues: corrosion and wear in pipelines and storage tanks, an increase in debris load resulting in diminished lubrication, blocked filters, or even harmful bacterial growth. As a result, increased water content can lead to infrastructure damage, higher maintenance costs, or even unwanted downtimes.Coulometric Karl Fischer titration is the method of choice for low water content in petroleum products. Using a Karl Fischer oven to vaporize the water present in the sample prior to titration not only greatly reduces matrix interferences, it can also be fully automated. This allows a reliable and cost-efficient analysis of the water content according to ASTM D6304 (Procedure B) in products such as diesel, hydraulic oil, lubricant, additive, turbine oil, and base oil.

Determination of fluoride, chloride, nitrite, nitrate, phosphate, and sulfate in cooling water using anion chromatography with conductivity detection after chemical suppression.

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.

The water content of melamine is determined according to Karl Fischer in a buffered solvent mixture at 50 °C.

Determination of borate and silicate in ultrapure water using anion chromatography with direct conductivity detection.

The water content of diesel fuel and petrol (gasoline) is determined according to Karl Fischer. Because of the low water content, the determinations are carried out by coulometric titration.

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 water content of 2-methyl-5-mercaptothiadiazole is determined according to Karl Fischer using a special solvent mixture to prevent unwanted side reactions.

This Application Note describes the determination of water content in pesticides using Karl Fischer titration.

The water content of aniline is determined according to Karl Fischer in buffered solvent.

Groundwater contains many minerals, but can be contaminated by sodium-rich leachate from landfills. Accurate Na determination in water is possible following AOAC 976.25 using the Na-ISE.

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.

The water content of beta-caprolactam is determined according to Karl Fischer.

In this application note, Karl Fischer titration is used to determine the water content of urea.

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 fluoride, chloride, nitrite, bromide, nitrate, phosphate, sulfite, and sulfate in river water using anion chromatography with conductivity detection after chemical suppression.

Fast IC means a high sample throughput. This is attained with short columns, relatively high flows and strong eluents. Applied to drinking water analysis this means: determining chloride, nitrate and sulfate within 3 minutes.

Beer is a popular beverage consumed by millions of people for enjoyment, despite its humble beginnings as a water purification technique in pre-modern times. Brewing beer requires large amounts of water which must adhere to strict alkalinity, hardness, and pH parameters to ensure uniformity in flavor and appearance between each batch. Alkalinity is introduced by carbonates and hydroxides in water which raise and buffer the pH. Hardness, balanced to a large degree by the alkalinity, comes from Ca and Mg ions, mainly present as hydrogen carbonates. Depending on the concentration ranges, the 2035 Process Analyzer or the 2060 Process Analyzer are ideally suited for the fully automatic execution of these important analyses, as well as additional parameters like pH or conductivity. These process analyzers can signal the plant’s distribution system to correct the water chemistry, ensuring consistent product quality. In addition to alkalinity and water hardness, numerous other parameters can also be determined (pH, conductivity, etc.).

Determination of fluoride, chloride, nitrite, bromide, nitrate, and sulfate in surface water using anion chromatography with conductivity detection after chemical suppression.

"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."

This Application Note describes an automated system with which the chloride content in various water samples can be determined. The high degree of automation (e.g., automated addition of acid and titer determination) reduces errors to a minimum and ensures outstanding reproducibility.

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.

Chlorinating drinking water can form carcinogenic byproducts. EPA Method 557 enables µg/L-level quantification of haloacetic acids using Metrohm IC-MS/MS technology.

The water content of potato chips is determined according to Karl Fischer using the oven method (140 °C).

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 water content of color paste is determined according to Karl Fischer.

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 TitrIC flex II system is the perfect combination of titration, direct measurement, and ion chromatography for fully automated analysis of all key parameters. These include pH, conductivity, hardness, anions, cations, as well as the calculation of the ion balance: comprehensive water analysis from one system.

In industrial cooling water systems, copper and its alloys are widely used because of their superior heat transfer properties. These materials are, however, susceptible to corrosion. Azoles are commonly used to protect copper and its alloys from corrosion. These corrosion inhibitors are quantified by ion chromatography with UV/VIS detection.

Karl Fischer titration can be used to determine the water content in N-acetyl-L-cysteine. Special solvent mixtures can be used to prevent unwanted side reactions in the Karl Fischer titration. The water content of N-acetyl-L-cysteine can thus be determined quickly and accurately, as is shown in this Application Note.

Determination of fluoride, acetate, propionate, formate, butyrate, chloride, nitrite, bromide, nitrate, benzoate, phosphate, sulfate, malonate, and oxalate in an industrial process water using anion chromatography with conductivity detection after sequential suppression.

The water content of bismuth subnitrate is determined according to Karl Fischer.

The water content of vinyl chloride is determined according to Karl Fischer.

The water content of explosive pellets is determined according to Karl Fischer after extraction with methanol.

Determination of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate in water from an agricultural irrigation system using anion chromatography with conductivity detection after chemical suppression.

Perchlorate in water is mainly due to anthropogenic sources such as fertilizers, fireworks, rocket fuel, etc. Trace analysis of perchlorate in water samples is a critical task. The high content of standard anions leads to large peaks that interfere with the very small perchlorate peak. In the heart-cut technique, the perchlorate fraction – widely freed of interfering anions – is re-injected onto the column thus providing a sharp peak.

Determination of traces of chlorite and bromate in Herisau tap water with direct injection using anion chromatography with conductivity detection after chemical suppression.

The water content of flour is determined according to Karl Fischer. To shorten the analysis times and to obtain more precise results, the determinations are carried out at 50 °C.

The water content of silicone oil is determined according to Karl Fischer by coulometric titration.

This Application Bulletin describes the determination of water in non-explosive and non-flammable gaseous samples using the coulometric Karl Fischer method. This method is ideal for very low water contents.

This Process Application Note details the simultaneous online analysis of H2S and NH3 in sour water which was previously treated in the sour water stripper (SWS). The method includes automatic cleaning and calibration. Fast and accurate results are continuously supplied for process control.

The water content of ethylene dichloride is determined according to Karl Fischer. As the sample may contain free chlorine, which interferes with the determination, separate KF reagents have to be used.

The water content of sweet liquorice is determined according to Karl Fischer. To dissolve the sample, a mixture of methanol and formamide is used as solvent and a high-frequency homogenizer as stirring device.

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.

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.

This application note describes the water content determination in penicillin by using volumetric Karl Fischer titration. Unwanted side reactions can be avoided by using special solvent mixtures.

«Dissolved oxygen» describes the amount of oxygen molecules (O2) which are dissolved in a liquid phase under certain conditions. In this white paper, two different methods for the analysis of dissolved oxygen, titration and direct measurement, are compared and contrasted to help analysts determine which method is more suitable for their specific applications. Here, we primarily focus on the determination of dissolved O2 in water. However, the same principle applies for other liquid phases such as non-alcoholic or alcoholic beverages.

The water content of lime is determined according to Karl Fischer using the oven method (150 °C).

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.

The water content of potassium chlorate is determined according to Karl Fischer using the oven method (300 °C).

This Application Note highlights near-infrared spectroscopy as a faster, cost-effective alternative to KF titration for predicting water content in diesel fuel.

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.

The water content of animal fat extract is determined according to Karl Fischer.

A sample of concentrated mineral acid is dissolved in anhydrous acetonitrile, and the water content titrated with a solution of TEOF in acetonitrile. The TEOF reacts exothermically with water in the presence of a strong acid (acting as a catalyst).

Chromate is allergenic, carcinogenic and extremely toxic. It is therefore subject to strict monitoring. It is present in different concentrations in drinking water, toys, textiles, leather and many other materials. Metrohm has developed various methods for ion chromatographic determination of chromium(VI) which, thanks to Inline Sample Preparation, are suitable for a variety of matrices and concentration ranges – from ng/L to mg/L.

The concentration of Fe(total) is determined in deionized water. The method is suitable for iron concentrations down to the mid µg/L range. Electrochemical deposition is not applicable for this method. A subtraction of the reagent blank is recommended. Fe(II) and Fe(III) give signals with the same sensitivity.

Nitrogen-based compounds are widely distributed in the environment and are essential growth nutrients for photosynthetic organisms. Therefore, it is important to monitor and control the amount of nitrogen compounds which are released into the environment.In this Application Note, a method to determine the nitrogen content in water by Kjeldahl digestion and distillation followed by a photometric or potentiometric titration according to ASTM D3590 is presented. The universality, precision, and reproducibility of the Kjeldahl method have made it the internationally recognized method for e.g. estimating the protein content in many matrices and it is the standard method to which all other methods are judged against.

Determination of glycolic acid, formic acid, glutaric acid, acetic acid, propionic acid, and butyric acid in paper industry process water using ion-exclusion chromatography with suppressed conductivity detection.

The rapid growth of the Earth's population has led to massive increases in the consumption of energy and resources and in the production of consumer products and chemicals. It is estimated that 17 million chemical compounds are currently on the market, of which 100,000 are produced on a large industrial scale. Many of these enter the environment. This leads to a demand for sensitive analytical procedures and high-performance analytical instruments.pH value, conductivity and oxygen requirement are important characteristics in water and soil analysis. The first two of these can be determined rapidly; for the third, the titration that is used is also the one used in numerous single determinations. This article describes several important standard-compliant determinations in water and soil analysis.

The water content of lyophilisates contained in vials is determined by Karl Fischer titration. Conditioned solvent (methanol) is injected into the vial to dissolve the sample and extract the water (ultrasonic bath). Afterwards the contents of the vial are transferred to the titration vessel to carry out the automatic determination.

The water content of cyclopropyl methyl ketone is determined according to Karl Fischer by coulometric titration using special reagents for aldehydes and ketones.

The water content of lemongrass oil is determined according to Karl Fischer. To prevent unwanted side reactions, special KF reagents for aldehydes and ketones are used and the determination is carried out at 0 ... 4 °C.

Determination of traces of iodide in bottled water using anion chromatography with UV/VIS detection.

Hexavalent chromium, also referred to as chromate or Cr(VI), is considered toxic and potentially carcinogenic, which is why its concentrations in drinking water should be kept as low as possible. Determination of Cr(VI) is performed by combining ion chromatography with ICP/MS. Separation takes place on the Metrosep A Supp 1 Guard/4.6.

The water content of smoked salmon and smoked trout is determined according to Karl Fischer.

The water content of acetophenone and benzophenone is determined according to Karl Fischer using special KF reagents for ketones/aldehydes to prevent unwanted side reactions.

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.

Determination of fluoride, chloride, nitrite, nitrate, and sulfate in a closed cooling water system using anion chromatography with conductivity detection after chemical suppression.

The water content of piperidine and piperazine is determined according to Karl Fischer using a buffered solvent mixture.

The water content of used lubricating oil is determined according to Karl Fischer by coulometric titration. To prevent unwanted side reactions special KF reagents are used.

The water content of organic peroxides is determined according to Karl Fischer using two-component reagents. To prevent any unwanted side reactions, the determinations are carried out at -20 °C.

Determination of magnesium, strontium, and barium in produced water using cation chromatography with direct conductivity detection.

Determination of fluoride, chloride, nitrite, bromide, nitrate, phosphate, sulfate, and iodide in a mineral water using anion chromatography with conductivity detection after chemical suppression.

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.

Drinking water which has been disinfected via the ozonation process can contain undesirable levels of bromate, a carcinogen, via oxidation of bromide in the raw water. Already several agencies including the World Health Organization have recommended concentration limits for bromate set in place to limit its risks to our health. Ion chromatography is mentioned in several analytical standards for the determination of disinfection byproducts (DBP) including bromate, such as EPA 300.1, 317.0, 321.8, 326.0, ASTM D6581, ISO 11206, and ISO 15061. Monitoring trace levels of bromate online means higher throughput and less time spent performing manual laboratory tests, and ensures quality drinking water is produced.

Determination of fluoride, chloride, nitrate, phosphate, and sulfate in surface water using anion chromatography with conductivity detection after chemical suppression; nitrite with electrochemical detection (conductivity and ELCD detectors in series).

The water content in Ca carbonate is determined by volumetric Karl Fischer titration.

Haloacetic acids (HAAs) are commonly produced as disinfection byproducts (DBPs) from water treatment processes. Some HAAs are regulated by the authorities and have been classified as potentially carcinogenic. They have traditionally been analyzed by gas chromatography (GC), a technique that requires time-consuming sample extraction and derivatization, leading to higher costs per analysis. Ion chromatography hyphenated to mass spectrometry (e.g., single or triple quadrupole MS systems) is a powerful tool that can handle many challenging analytical tasks such as measuring μg/L levels of HAAs in potable water samples. This White Paper explains the benefits of using this hyphenated technique for the accurate measurement of HAAs in potable water.

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 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 presence of water in expandable polystyrene (EPS) can have a negative impact on the thermal insulation properties, as it increases thermal conductivity. If EPS is exposed to a high moisture environment, additional water may be absorbed, which can further affect thermal insulation.Direct analysis of the moisture content by Karl Fischer titration requires the water to be extracted from the EPS, which involves several time-consuming steps. Therefore, determination of the water content with an oven system is preferred. As EPS expands when heated, the use of sample boats, as required by ASTM D6869, is not possible, as the EPS will contaminate the oven system. This Application Note describes the determination of water content in EPS using an oven system with closed sample vials. A determination takes about 7 to 14 min depending on the water content of the sample and the sample size.

The automated system Basic water analysis determines conductivity, pH value, and alkalinity in all kind of water samples. The high degree of automation (e.g., automated sample addition, automated calibration as well as automated titer and cell constant determination) minimizes errors and guarantees an outstanding reproducibility.

The determination of the water content of soft contact lenses using NIR spectroscopy is described in this Application. A liquid sample kit with gold diffuse reflector was used for measuring the lenses in transflexion mode. A PLS model was developed for predicting the water content.

The water content of 2-methyl-1,3-butadiene and 2,5-norbornadiene is determined according to Karl Fischer using a special solvent mixture to prevent unwanted side reactions.

Determination of trace levels of chloride, nitrate, phosphate, and sulfate in a boiler feed water using anion chromatography with conductivity detection after chemical suppression.

The water content, also called moisture content, of plastics is an important quality parameter, as it affects the properties and processability of some plastics. A high water content can lead to degradation of the plastic by hydrolysis or cause surface imperfections. Additionally, it can affect the physical properties of some plastics.For this analysis, the oven technique is used, as volatile compounds present in plastics will interfere, if the water content is directly determined by coulometric Karl Fischer titration. The water content determination in polycarbonate pellets, performed with the 885 Compact Oven Sample Changer and 899 Coulometer, is described in this Application Note.

The water content determination by volumetric Karl Fischer titration is one of the most important analyses worldwide. Using an OMNIS system consisting of an OMNIS Titrator and an OMNIS Sample Robot, the fully automatic analysis of water content is possible in various products and matrices. The OMNIS Sample Robot is capable of running several different titrations in parallel. In this Application Note, we present the results of a volumetric Karl Fischer titration run in parallel to an aqueous acid-base titration on the same system. The water content is not influenced by the parallel running aqueous titration, allowing the combination of potentiometric titrations and Karl Fischer titrations on the same automated system.

The determination of disinfection byproducts is essential for drinking water manufacturers. This Application Note shows the determination of chlorite and bromate in addition to the standard anions. In order to reduce eluent consumption, separation takes place on a Metrosep A Supp 5 - 250/2.0 Microbore column, followed by conductivity detection after sequential suppression.

Process water from flue gas desulfurization mainly contains sulfite and sulfate. Besides these two main components, other sulfur species may be formed in the process. This application describes the determination of such late-eluting sulfur species with ion chromatography applying a Dose-in gradient. The applied gradient profile enables the resolution of amidosulfonate, dithionate, and imidodisulfonate besides thiosulfate, thiocyanate, major anions, and acetate.

Determination of acetate, propionate, formate, and chloride in water using anion chromatography with conductivity detection after chemical suppression.

Near-infrared spectroscopy (NIRS) can determine water content in PGME (propylene glycol monomethyl ether) within seconds as shown in this Application Note.

This Application Note describes the determination of the water content in tablets using automated volumetric titration including sample preparation (MATi 11).

"Molybdenum is an essential trace element for plant growth. Since it occurs in natural waters only in trace amount, a very sensitive method of determination is needed. Using the following polarographic method, it is possible to determine 5·10-10 mol/L resp. 50 ng/L.The principle of the method is based on the reaction between the molybdate ion MoO42- and the complexing agent 8-hydroxy-7-iodo-quinoline-5-sulfonic acid (H2L) to form a MoO2L22- complex, which is adsorbed on the mercury electrode. The adsorbed Mo(VI) is reduced electrochemically to the Mo(V) complex. The hydrogen ions present in the solution oxidize Mo(V) again spontaneously to form the Mo(VI) complex, which is thus newly available for electrochemical reduction. This catalytic reaction is the reason for the high sensitivity of the method.Tungsten W(VI) exhibits practically the same electrochemical behavior as molybdenum, but is not described in detail in this Application Bulletin."

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.

Urea is not a typical analyte for ion chromatography. In combination with MS, however, IC is the method of choice for the trace analysis of urea in ultrapure water. This Application Note shows the determination of urea concentrations in the ppb range using the Metrosep C 6 - 250/4.0 column.

Perchlorate contamination in drinking water may have different sources. Besides natural deposits, anthropogenic sources like fertilizers and rocket fuel residue add to hazardous water contamination. Perchlorate interferes with iodine uptake into the thyroid gland. Newborns and children are particularly vulnerable, affected as thyroid hormones are essential for growth. Besides ion chromatography (IC) followed conductivity detection, IC hyphenated with an MS detector can be used to measure perchlorate down to sub-µg/L levels. In this application IC is hyphenated with a triple-quadrupole MS (IC-MS/MS) for perchlorate determination in order to meet the requirements of EPA 332.0. This IC-MS/MS setup avoids the possible interference of sulfate.

Trace cation analysis in high purity water (sub-μg/L range) requires cation chromatography after sequential suppression and intelligent Preconcentration Technique (MiPCT). Trace cations in deionized water (DI) are determined and the method detection limit (MDL according to US EPA) as well as the limit of detection (LOD = 3 x S/N) is calculated. MDL and LOD are very similar in the lowest ng/L range for this setup with 6 mL preconcentration volume.

This Bulletin describes the automatic measurement of conductivity in water samples with low electrical conductivity in accordance with USP<645>. Conductivity measurement is demonstrated on the example of ultrapure water, which is used, among other things, to produce injection solutions in the pharmaceutical sector.

Determination of acetic, propionic, butyric, valeric, and caproic acid in produced water using anion chromatography with conductivity and MS detection after post-column addition of ammonia for MS detection and inline sample preparation by dialysis.

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.

LC-MS/MS quantification methods are commonly used to determine trace levels of organic compounds. However, highly polar reversed phases (RPs) lack sufficient retention for very polar compounds, or they fail for charged organics. Separation using ion chromatography (IC) and subsequent MS/MS detection is an innovative alternative approach that combines the fast elution and flexibility of the IC system with the excellent resolution and high sensitivity of the MS/MS detector. This poster presents a fast, robust and reliable IC-MS/MS method for the detection of HAAs and other ionic analytes using the high-end MS/MS system QTRAP 6500+ from SCIEX coupled to a the 940 Professional IC Vario One SeS/PP/HPG instrument. This analytical setup is able to identify and quantify the presence of HAAs at trace levels with LLODs between 0.02 μg/mL and 0.2 μg/L on a single HAA. This capability easily fulfills the sensitivity requirements specified in EU Drinking Water Directive, which specifies a maximum residue level (MRL) of 60 mg/mL for the sum of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid present in the representative sample.

Fast IC means short run times and a high sample throughput. This is attained using short columns and strong eluents. Drinking water (including fluoride) is analyzed on the Metrosep A Supp 5 - 100/4.0 under the same conditions as in AN-S-322.

Determination of trace levels of chloride, nitrate, phosphate, and sulfate in boiler feed water using anion chromatography with conductivity detection after chemical suppression.