Application Finder

Fast and handsome IC! Outstanding peak shapes on columns with the standard flow rate and a strong eluent. When the high-capacity Metrosep C 6 - 250/4.0 is used, this usually means long retention times. A strong eluent allows however the determination of the cations in drinking water in a short run time with very symmetrical peaks.

Sequential suppression in cation chromatography significantly improves detection limits. The determination of the blank value of the sample vial being used is thus essential for being able to achieve such low detection limits. The leaching tests of various sample vials proceed with the intelligent Preconcentration Technique with Matrix Elimination on the Metrosep C Supp 1 - 250/4.0 column with conductivity detection following sequential suppression. The 50 mL Corning® Cell Culture Flasks from Sigma-Aldrich (CLS430168) exhibit the lowest blank values.

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®.

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®.

The combination of 850 Professional IC, 858 Professional Sample Processor, Dosino and MagIC NetTM software offers a variety of sophisticated ion chromatographic sample preparation techniques. One of these is the automated inline dilution of samples.After the first sample injection, MagIC NetTM verifies if the area of the sample peak lies within the calibration range. If the measured peak area is outside these limits, the software calculates the appropriate dilution factor, dilutes and automatically re-injects the sample. For all investigated ions (Li+, Na+, K+, Ca2+, Mg2+, F-, Cl- , NO2-, Br-, NO3-, SO42- ), automated logical dilution yielded coefficients of determination (R2) better than 0.9999. Direct-injection recoveries for cations and anions were within 98.6…99.5% and 93.4…100.4% respectively. In contrast, after logical dilution, recoveries for cations and anions were within 100.1…102.9% and 98.2…102.6% respectively. The relative standard deviations for all determinations involving diluted sample solutions were smaller than 0.91%.

This Application Note shows the selectivity of the Metrosep C Supp 1 - 250/4.0 column for alkyl and ethanol amines in addition to standard cations under isocratic conditions. Quantification takes place using conductivity detection following sequential suppression.

Thermometric titration of nickel in electroless plating solution with disodium dimethylglyoximate.

Automated thermometric titration of the nickel content of electroless nickel plating solutions. The determination is suitable for fully automated titration employing a 814 Sample Processor.

Determination of Sn(II) and sulfuric acid in an acidic tin plating bath by potentiometric titration.

Determination of sodium, potassium, calcium, and magnesium in the water soluble fraction of a washing powder using cation chromatography with direct conductivity detection.

The Metrosep C 6 columns have a higher capacity than those of the Metrosep C 4. The present Application Note describes the exceptional separating efficiency for standard cations with the three Metrosep C 6 column lengths available. The outstanding sodium-ammonia separation is particularly noteworthy.

Determination of lysine as well as sodium, ammonium, potassium, and calcium in bulk lysine using cation chromatography with direct conductivity detection.

Partial loop injection is a well known way of sample introduction to HPLC. In ion chromatography, it is not yet used to a large extent. Liquid handling with Metrohm's Dosino technology now enables to use partial loop injection on a highly reproducible and accurate level. It includes multi-level calibration out of one standard solution. This Application Note shows its use for parallel anion and cation determination in tap water applying one single Sample Processor. The anion results are shown in Application Note S–287.

Determination of citrate, fluoride, lactate, and acetate in a plating bath using ion-exclusion chromatography with direct conductivity detection.

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.

Cation chromatography with sequential suppression enables the determination of cations in their hydrogen carbonate form. The eluent – usually nitric acid – is converted into carbonic acid. Following its decomposition into carbon dioxide and water, the former is continuously removed by the CO2 suppressor. The reduction of baseline noise thus achieved permits the lowering of the detection limits and improves reproducibility, even at very low cation concentrations. This Note shows the reproducibilities determined for cation concentrations of 10 µg/L.

This Application Note presents ion chromatography as a precise method to analyze anions in beer as well as cations with non-suppressed conductivity. Automation with Inline Ultrafiltration is also discussed.

Methanedisulfonic acid (MDSA) is used as a catalyst in chromium plating baths. The MDSA concentration in the bath must be known in order to monitor the chromating. The analysis of a bath sample requires dilution by a factor of 2,500. This Application Note shows the automatic Inline Dilution that takes place in two steps. While one sample is being analyzed, the time-optimized dilution of the next sample is already running. The MSM is regenerated using an 800 Dosino and the STREAM setup: The eluent is used for rinsing the regenerated MSM after exiting the detector.

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

The concentration of Fe(total) is determined by polarography in oxalate buffer pH 2. This method is suitable for iron concentrations in the mg/L range.

The concentration of Zn in a zinc phosphatation bath is determined by polarography in ammonia buffer pH 9.3.

The concentration of Ni in a Zn phosphatation bath is determined by polarography in ammonia buffer pH 9.3.

The concentration of Cd in a Zn phosphatation bath is determined by polarography in HCl electrolyte.

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

Determination of sodium hypophosphite in electroless plating solutions.

Determination of cyanide in alkaline plating baths by potentiometric titration with silver nitrate using the Ag-Titrode.

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

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

The concentration of Cu in a cyanidic Cu bath is determined by polarography.

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).

This article describes the composition of atmospheric inorganic gases and aerosols in the Southeast and Northwest of the United States during a time period of several weeks. The semicontinuous sampling in hourly cycles takes place using the MARGA system from Metrohm Applikon. The temporal resolution of the aerosol and gas composition makes it possible to generate statements regarding the chemical origin and hygroscopicity of the particles. These are fundamental for rating the influence of aerosols on the climate.

Methods are described for the potentiometric analysis of the following bath components:Brass plating bath: copper, zinc, free cyanide, ammonium, carbonate, and sulfite.Bronze plating bath: copper, tin, and free cyanide.

Determination of sodium, potassium, DMEA (dimethylethanolamine), calcium, choline, and magnesium in a saline solution using cation chromatography with direct conductivity detection.

This Application Note covers the formation of calcium carbonate from solution.

Determination of fluoride, MSA (methylsulfonic acid), EDSA (ethyldisulfonic acid), and MDSA (methyldisulfonic acid) using anion chromatography with conductivity detection after chemical suppression.

Determination of Cu in a nickel sulfate bath containing surfactants after UV digestion.

The concentration of Cu in a Ni plating bath is determined by polarography in chloride-containing acetate buffer at pH 4.7.

This application focuses on the simultaneous analysis of cations and suppressed anions with a dual channel Metrohm IC operated by OpenLab CDS.

OpenLab CDS is the newest generation of chromatography data systems from Agilent, combining chromatography and mass spectrometry in a single software platform. The Metrohm IC Driver for OpenLab CDS integrates Metrohm IC instrumentation for full control and data acquisition. The present application describes the simultaneous analysis of anions and cations in a soft drink with a dual channel IC system. Eluent is prepared by applying Inline Eluent Production.

Determination of chloride, nitrite, and sulfate in a used zinc bath using anion chromatography with conductivity detection after chemical suppression.

The Application Bulletin describes the determination of suppressor in acid copper baths by smartDT. The determination of suppressor with dilution titration (DT) involves numerous additions with standard solution or sample to reach the evaluation ratio. Usually fixed, equidistant addition volumes are used. With smartDT, variable addition volumes are used that are dynamically calculated by the software. At the beginning, the volumes are bigger. Towards the evaluation ratio, the addition volume becomes smaller to guarantee a good accuracy of the result. The operator defines the first and the smallest addition volume to be used. All volumes in between are calculated by the software considering the progress of the determination. The time saving with smartDT compared to a classic DT with fixed addition volumes can be up to 40%. smartDT is suitable for nonlinear regression and quadratic regression as well as linear interpolation. It can be used for determination of suppressor in acid copper baths as well as in tin and tin-lead baths and works with 1, 2, and 3 mm Pt working electrodes. A 800 Dosino is required for the automatic addition of suppressor standard or sample. The method can also be used in fully automated systems.

The concentration of Pd in an activator bath is determined by polarography in ammonium chloride electrolyte.

The concentration of Fe(total) is determined by polarography in an alkaline electrolyte containing triethanolamine (TEA) and KBrO3. All reagents typically contain iron impurities. Therefore a subtraction of the reagent blank is recommended.

Determination of fluoride in a chromium plating bath by direct potentiometry using the F-ISE.

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 Ti in a Ti pickle bath is determined by polarography in an oxalic acid electrolyte.

Drinking water analysis is strongly regulated by standards. In this Application Note, the cation determination according to ISO 14911 is shown. The Metrosep C 4 - 150/4.0 is the optimum separation column for this purpose.

N-methyldiethanolamine and piperazine are used in scrubber solutions, e.g., in the natural gas process. Testing this type of samples by ion chromatography requires a good resolution and the separation of amines from standard cations. The separation is achieved on a Metrosep C 4 - 150/4.0 column applying direct conductivity detection.

The concentration of Ni in a Ni plating bath is determined by polarography in ammonia buffer pH 9.6.

A typical electrochemical impedance spectroscopy (EIS) experimental setup consists of an electrochemical cell, a potentiostat/galvanostat, and a frequency response analyzer (FRA). This Application Note introduces common EIS experimental setups as well as details of the main experimental parameters.

Thermometric titration can solve application problems that potentiometry cannot solve at all, or at least not satisfactorily.

Electrochemical impedance spectroscopy (EIS) is a widely used multidisciplinary technique for characterizing the behavior of complex electrochemical systems. EIS is employed in the study of a range of complex systems including batteries, catalysis, and corrosion processes. This Application Note focuses on the basic principles of EIS measurements.

Determination of hydroxide and carbonate in alkaline plating baths by potentiometric titration with HCl using the combined glass electrode.

This Application Note explains manual and automated iR drop correction with electrochemical impedance spectroscopy and cautions against using less accurate methods.

Gallium is determined at a pH value of 4.7 using back titration with zinc sulfate. Xylenol orange is used as the indicator for visualization of the equivalence point. The equivalence point is determined with the Optrode at a wavelength of 610 nm.

Chromate (Cr(VI)) is regarded as being carcinogenic, mutagenic and damaging to DNA, which is why Cr(VI) concentrations are to be kept as low as possible. The EU Toy Safety Directive 2018/725 defines migration limit values for the release of chromate from toys. The "HCl migration solutions" are diluted with a buffer before 2,000 µL are injected via Metrohm intelligent Preconcentration Technique with Matrix Elimination (MiPCT-ME). Determination is performed with VIS detection following derivatization with diphenylcarbazide.

The study of adverse effects of air pollution requires semi-continuous, rapid and accurate measurements of inorganic species in aerosols and their gas phase components in ambient air. The most promising instruments, often referred to as steam collecting devices, are the Particle-Into-Liquid-Sampler (PILS) coupled to wet-chemical analyzers such as a cation and/or anion chromatograph (IC) and the Monitoring instrument for AeRosols and GAses (MARGA) with two integrated ICs. Both instruments comprise gas denuders, a condensation particle growth sampler as well as pump and control devices. While PILS uses two consecutive fixed denuders and a downstream growth chamber, the MARGA system is composed of a Wet Rotating Denuder (WRD) and a Steam-Jet Aerosol Collector (SJAC). Although the aerosol samplers of PILS and MARGA use different assemblies, both apply the technique of growing aerosol particles into droplets in a supersaturated water vapor environment. Previously mixed with carrier water, the collected droplets are continuously fed into sample loops or preconcentration columns for on-line IC analysis. While PILS has been designed to sample aerosols only, MARGA additionally determines water-soluble gases. Compared to the classical denuders, which remove gases from the air sample upstream of the growth chamber, MARGA collects the gaseous species in a WRD for on-line analysis. In contrast to the gases, aerosols have low diffusion speeds and thus neither dissolve in the PILS denuders nor in the WRD. Proper selection of the ion chromatographic conditions of PILS-IC allows a precise determination, within 4 to 5 minutes, of seven major inorganic species (Na+, K+, Ca2+, Mg2+, Cl-, NO3- and SO4 2-) in fine aerosol particles. With longer analysis times (10-15 minutes) even airborne low-molecular-weight organic acids, such as acetate, formate and oxalate can be analyzed. MARGA additionally facilitates the simultaneous determination of HCl, HNO3, HNO2, SO2 and NH3.PILS and MARGA provide semi-continuous, long-term stand-alone measurements (1 week) and can measure particulate pollutants in the ng/m3 range.

This poster provides an overview of ion chromatographic methods combined with inline sample preparation for the determination of anions and water-extractable cations in biofuels. In addition, the determination of the oxidation stability is described.

The ASTM standard G100 is an electrochemical method to test localized corrosion of aluminum 3003-H14 and other alloys. A cyclic galvanostatic staircase polarization (galvanostaircase) is composed of an upward and a downward scan. The potential values at the end of each step are collected and linearly fitted, and the potential values at zero current are found.

The rotating cylinder electrode (RCE) is successfully used in a laboratory environment to generate a turbulent flow at the surface of a sample, simulating realistic pipe flow conditions. In this application note, the corrosion rate is measured and compared between quiescent and turbulent flow conditions, while keeping all the other experimental conditions unchanged. The linear polarization (LP) technique was used together with the RCE (with and without rotation).

Iron sucrose injections are used during the treatment of iron deficiency anemia. They contain a mixture of ferric iron (Fe3+) and ferrous iron (Fe2+). Ferrous iron content may be determined by subtracting the ferric iron content from the total determined iron content. Yet, this increases the measurement error due to error propagation. Alternative determination of iron(II) with cerium(IV) by potentiometric titration may be hampered, as the equivalence point cannot be determined unequivocally. Determination by thermometric titration is a more robust and therefore more reliable alternative, as this method is unaffected by the sample matrix. Here, the endpoint of the titration is indicated by a fast responding thermometric sensor. Endpoint detection is further improved by spiking the sample with 0.2% ammonium iron(II) sulfate (FAS), increasing the reliability of the determination. Compared to potentiometric titration, thermometric titration is faster and more convenient as no sensor maintenance is required. One determination takes about 2–3 minutes.

Thorium is titrated with EDTA at a pH value of 4.9. Xylenol orange is used as the indicator for visualization of the equivalence point. The equivalence point is determined with the Optrode at a wavelength of 574 nm.

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.

Standardization of 0.1 mol/L ammonium ferrous sulfate solution for use in thermometric titration of Cr(VI) solutions.

Standardization of disodium dimethylglyoximate by thermometric titration with standard Ni(II) solution.

Determination of sulfate in cement by indirect potentiometric titration with EDTA using platinum and tungsten electrodes.

Determination of fluoride, chloride, and nitrate in a solution of NiSO4, ZnSO4 in sulfuric acid using anion chromatography with conductivity detection after chemical suppression.

The coupling of highly efficient ion chromatography (IC) to multi-dimensional detectors such as a mass spectrometer (MS) or an inductively coupled plasma mass spectrometer (ICP/MS) significantly increases sensitivity while simultaneously reducing possible matrix interference to the absolute minimum. By means of IC/MS several oxyhalides such as bromate and perchlorate can be detected in the sub-ppb range. Additionally, organic acids can be precisely quantified through mass-based determination even in the presence of high salt matrices. By means of IC-ICP/MS different valence states of the potentially hazardous chromium, arsenic and selenium in the form of inorganic and organic species can be sensitively and unambiguously identified in one single run.

This Bulletin describes fluoride determination in various matrices with the help of the ion-selective fluoride electrode (F-ISE). The F-ISE is comprised of a lanthanum fluoride crystal and exhibits a response in accordance with the Nernst equation across a wide range of fluoride concentrations.The first part of this Bulletin contains notes regarding the handling and care of the electrode and the actual fluoride determination itself. The second part demonstrates the direct determination of fluoride with the standard addition technique in table salt, toothpaste and mouthwash.

Chromate (Cr(VI)) is considered toxic and potentially carcinogenic, which is why its concentrations in children's toys should be kept as low as possible. The EU directive 2009/48/EC defines limit values for the migration of chromate from children's toys. The hydrochloric-acid-containing migration solution is diluted with a buffer. 2000 μL of this solution are injected automatically using intelligent preconcentration technology and matrix elimination. Detection takes place via ICP/MS.

As a rule, soil contains small percentages of chromium that originate chiefly from rock weathering processes, although anthropogenic sources also exist. The speciation analysis of trivalent – Cr(III) – and hexavalent chromium – Cr(VI) – is important, because the former is a trace element and the latter is highly toxic. The two chromium species are separated as Cr(III)-EDTA-complex and chromate on the Metrosep A Supp 4 - 250/4.0 column. Mass spectrometric isotope dilution analysis (SIDMS) is used for quantification.

Chromium is extracted from chromite ore and is an important part in the production of stainless steel. Chromium is mainly divalent, trivalent and hexavalent in its compounds. In contrast to chromium(III), which is an important trace element and one that is only sparingly soluble in water, hexavalent chromium is extremely toxic and very water-soluble. Cr(VI) is furthermore an important raw material for industry. It must be determined rapidly and precisely in the lower µg/L range in wastewater. Metrohm Applikon offers an array of process analyzers for the analysis of wastewater streams which determine chromium precisely and reproducibly using photometry.

Tin with EDTA forms very stable complexes in its divalent and tetravalent forms. Hydroxo complexes form in alkali media, which is also why tin is titrated in an acidic medium (pH 2.1). Xylenol orange is used as the indicator. The equivalence point is determined with the Optrode at a wavelength of 574 nm.

The determination of chromium(VI) polymers using anion exchange chromatography with UV/VIS detection after post-column reaction with diphenylcarbazide as per IEC 62321 method for RoHS testing.

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.

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).

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.

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.

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

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

The objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. Recommendations for the validation of analytical methods can be found in ICH Guidance Q2(R1) Validation of Analytical Procedures: Text and Methodology and in USP General Chapter <1225> Validation of Compendial Procedures. The goal of this white paper is to provide some recommendations for the validation of titration methods.

Potassium is a primary macronutrient for plants, as it plays an important role in water regulation as well as plant growth. In NPK fertilizers, potassium is present besides nitrogen and phosphorus, which are the other two primary macronutrients. Knowing the quality and content of a NPK fertilizer allows an optimal fertilizer management for a planned culture, saving costs and increasing profitability.Traditionally potassium is determined gravimetrically or by flame photometry. In this Application Note, an alternative method is presented, where potassium is determined a precipitation titration. Various solid and liquid NPK fertilizers with potassium contents between 10 and 27% were analyzed. After the removal of any present ammonia, the potassium can be determined reliably in about 5 minutes.

Determination of aluminum in cement by photometric back-titration of the EDTA excess with zinc sulfate using the 610 nm Spectrode.

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

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.

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.

Potentiometric titration is an accurate method for determining chloride content. For detailed instructions and troubleshooting tips, download our Application Bulletin.

This Bulletin describes a simple method for the determination of the calcium content in dairy products. The use of CuEGTA and the ion-selective copper electrode (Cu ISE) as indicator electrode allows the determination to be performed without time-consuming sample preparation. If the complexing agent EDTA is used as titrant instead of EGTA, the sum of calcium and magnesium is obtained. The magnesium content can then be calculated from the difference between the results of the two titrations.

This bulletin deals with the automated determination of calcium and magnesium in commercially available finished milk products using a 859 Titrotherm and a 814 USB Sample Processor. Calcium and magnesium in milk can be rapidly and easily titrated thermometrically using a standard solution of Na4EDTA as titrant.Thermometric titrations are conducted under conditions of constant titrant addition rate. The molarity of the titrant is computed automatically in tiamo (software) using the SLO command. Results are reported as mg Ca and Mg/100 mL.

This bulletin discusses automated determination of sodium in milk products available to the public using a 859 Titrotherm and a 814 USB Sample Processor. The sodium content of milk can be rapidly and easily titrated thermometrically with a standard solution of Al3+ as titrant. Thermometric titrations are conducted under conditions of constant titrant addition rate. The molarity of the titrant is computed automatically in tiamoTM (software) with the SLO command. Results are reported as mg Na/100 mL. In addition to this application bulletin, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

Determination of sodium in salts, process solutions, and foods.

Standardization of titrant for direct determination of sodium.

Standardization of ~1mol/L tetrasodium EDTA solutions for thermometric complexometric analysis.

Titration of an unfiltered suspension of the sample with a standardized solution of aluminum containing a stoichiometric excess of potassium ions in the presence of ammonium hydrogen difluoride at ~ pH 3 to give an exothermic reaction, forming insoluble NaK2AlF6. The titrant is standardized against a solution prepared from anhydrous sodium sulfate or sodium carbonate. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube: https://youtu.be/lnCp9jBxoEs

Standardization of 1 mol/L tetrasodium EDTA (Na4EDTA) solutions by titration with standard magnesium solution.

A measured amount of milk is treated with trichloroacetic acid to coagulate milk solids and liberate calcium and magnesium as dissociated ion. The coagulated milk is filtered or centrifuged, and an aliquot of the clear serum is titrated with a standard solution of 1 mol/L tetra-sodium EDTA to thermometrically determined endpoints for Ca and Mg. Acetylacetone is added to alter the Ca- and Mg- EDTA stability constants for better endpoint sharpness.

This Application Note describes the determination of total sodium content in canned fish products using thermometric titration. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

This application note describes the determination of the total sodium content in soy milk products. The methodology may also be applied to the determination of sodium in milk products from cows, goats and sheep. A standard addition technique is employed to permit the accurate and precise determination of sodium at relatively low levels.

Sodium can be determined thermometrically in cheese without sample preparation and addition of additives. A homogenizer is responsible for distribution and stirring. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

Determination of free alkali in sodium hypochlorite by potentiometric titration with hydrochloric acid using a combined glass electrode.

Determination of traces of calcium in brine by photometric titration with 1,2-diaminocyclohexanetetraacetic acid using the 610 nm Spectrode.

Determination of calcium in cheese by potentiometric titration with EGTA using the Cu-ISE.

This application note shows how to determine the bismuth content automatically in aqueous solution with potentiometric titration.

In this Application Note, the determination of calcium in milk is shown with the copper ion-selective electrode which is less sensitive to contamination from proteins.

Magnesium can be determined with the Cu ISE. A small amount of Cu-EDTA complex is used as an indicator, as the Cu ISE is not selective for magnesium itself.

Lead is determined at pH 4 to 5 using back titration with zinc sulfate. Xylenol orange is used as an indicator for visualization of the equivalence point. The equivalence point is detected with the Optrode at a wavelength of 574 mm.

Determination of zinc in a herbal pharmaceutical drug against cancer of the prostate.

The concentration of Pd in pharmaceutical products is determined by polarography after wet digestion.

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

Cr(III) forms an electrochemically active complex with diethylenetriaminepentaacetic acid (DTPA), so does Cr(VI) after in situ reduction on the surface of the HMDE. Depending on the sample preparation procedure and the waiting time after the addition of the complexing agent, the different chromium species can be differentiated:Total active chromium [total concentration of Cr(VI) and free Cr(III)]:The measurement is carried out immediately after the addition of DTPA.; Cr(VI): Between the addition of DTPA and the start of the analysis a minimum waiting time of 30 min is necessary. During this waiting time the Cr(III)-DTPA complex becomes electrochemically inactive.; Cr(III): The difference between the total active Cr and Cr(VI).; Totalchromium: Determination of total active Cr after UV digestion.;

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.

This Application Note describes the polarographic determination of thiourea in electroplating baths used in the production of copper indium gallium diselenide (CIGS) or copper indium diselenide thin-film solar cells (CIS). Cadmium sulfide (CdS) from the electrolyte solution is deposited as a thin film on the CIS or CIGS absorber layer via chemical bath deposition (CBD).

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.

Metrohm intelligent Partial Loop Technique (MiPT) is a versatile injection mode in IC. In this application, injection volumes range from 4 to 200 µL (corresponding to 0.5 - 10 mg/L) using the 250 µL loop. Here, the use of 2 and 5 mL Dosing Units are compared.

The relative permittivity εr, also known as dielectric constant, is of great importance in materials characterization. It can be defined as the ratio between the amount of electrical energy stored in a material and the amount of electrical energy stored in a vacuum. One of the easiest way to obtain the relative permittivity is to calculate it from capacitance values. In this Application Note, five techniques to retrieve capacity values have been compared.

Determination of sodium in seawater and similar brines. This procedure is suitable for the analysis of sodium in seawater contaminated with sodium aluminate solutions emanating from alumina refineries, and seawater which has been used for the neutralization of alumina refinery waste («red mud») slurries.

Determination of trace chloride in cement and clinker by potentiometric titration with silver nitrate using the Ag-Titrode.

Determination of chromium(VI) (chromate) in leather extract using anion chromatography with UV/VIS detection after post-column reaction (PCR) and inline dialysis for sample preparation.

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

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.

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.

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.

This White Paper discusses USP <1225> and how ion chromatography determines active ingredients in pharma products (assays) as well as identifies impurities and degradation components.

The determination of cyanide is very important not only in electroplating baths and when decontaminating wastewater but, due to its high toxicity, also in water samples in general. Concentrations of 0.05 mg/L CN- can already be lethal for fish.This Bulletin describes the determination of cyanide in samples of different concentrations by potentiometric titration.Chemical reactions:2 CN- + Ag+ → [Ag(CN)2]-[Ag(CN)2]- + Ag+ → 2 AgCN

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.

Determination of calcium and magnesium in a dolomite sample using cation chromatography with direct conductivity detection.

Determination of strontium and barium in monoethylene glycol using cation chromatography with direct conductivity detection.

A cardioplegic solution protects the ischemic myocardium from cell death. It is applied together with hypothermia e.g. in open heart surgery. Here the simultaneous determination of aspartic acid, glutamic acid, tris(aminomethyl)aminomethane (TRIS), sodium and potassium in such a solution is given. The two amino acids can be determined as they are partially in the triple protonated ammonium form at the eluent pH. Determination is achieved by direct conductivity detection.

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.

Standardisation of sodium tetraphenylborate (NaTPB) solution for the determination of potassium and for nonionicsurfactants.

Determination of sodium as chloride in ketchups, sauces and, similar food products.

Determination of calcium and magnesium in seawater. The method is suitable for determining the effect of caustic soda and alumina refinery aluminate solutions on the calcium and magnesium content of seawater.

A measured amount of salt is titrated directly with a solution of 1 mol/L tetrasodium EDTA to thermometrically determined endpoints for Ca and Mg. Acetylacetone is added to alter the Ca and Mg EDTA stability constants for better endpoint sharpness.

This Application Note describes the determination of the total sodium content in instant noodles which are also called «two minute noodles» in some countries. These products contain considerable amounts of sodium (at least 50% of the recommended daily dosage), which means that precise analysis of the sodium content is required. Argentometric titration of the chloride content (assuming that the sodium content in the noodles originates exclusively from the sodium chloride that is added to them) is unsuitable for precise analysis, as the nutrient contents listed on the product packaging document the presence of additional sodium salts other than sodium chloride. Thermometric titration enables fast and direct determination of sodium. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

Speciation analysis of iron is important, given that its oxidation level has a great influence on environmental response, not only with respect to its absorption by organisms but also to the transport and the storage of the element. Iron(II) and Iron(III) are separated on the Metrosep A Supp 10 S-Guard/4.0 column. IC-ICP/MS with isotope dilution is used for quantification.

In this Process Application Note, the analysis of low concentrations of calcium and magnesium (0–20 µg/L) in brine is addressed. The presence of calcium and magnesium can shorten the performance and lifetime of the membranes used in the chlor-alkali industry for the production of chlorine. Accurate online monitoring of the hardness is needed in several stages of the process. Other parameters such as acidity, carbonate, hydroxide, silica, alumina, ammonia, iodate and chlorine can also be analyzed online.

Determination of chloride, nitrate, and sulfate in cobalt acetate solution using anion chromatography with conductivity detection after sequential suppression using Metrohm Inline Dilution.

Manganese is determined as Mn(II) in aqueous solutions at pH 10 with Eriochrome Black T as indicator. Ascorbic acid is added to ensure that manganese is present in its bivalent form. The precipitation of water-insoluble manganese hydroxide is prevented by adding triethanolamine (TEA). The Optrode is used for detection at a wavelength of 610 nm.

Lithium salts (e.g., lithium carbonate and lithium hydroxide) are used in myriad applications. Lithium hydroxide is used for the production of lithium stearate, an important engine lubricant. In addition, it is utilized as an air purifier due to its ability to bind carbon dioxide. While the majority of lithium carbonate is used for aluminum production, it is also used for the glass and ceramic industry. It lowers the melting point of these materials, lowering the associated electricity costs and making it cheaper to produce them.For all of these applications, it is important to know the quality of the pure lithium salts used in the various production processes. This Application Note presents an easy method for the assay of lithium hydroxide and lithium carbonate on an automated OMNIS system.

Lithium nitrate is an oxidizing agent used in the manufacture of red-colored fireworks and flares. In addition, the lithium nitrate trihydrate compound absorbs heat well and can be used for thermal energy storage. Since lithium nitrate is a hygroscopic substance, its purity must first be verified before it is used for synthesis or other applications. The purity assay is done by a fully automated precipitation titration between lithium and fluoride in an ethanolic solution. The benefit of titration is that the lithium nitrate does not need to be diluted after dissolving in ethanol as with other techniques such as ICP-MS.

Dye samples are analyzed for trace chromate. Chromate (Cr(VI)) is considered toxic and potentially carcinogenic for which reason its concentrations should be as low as possible. This sample is prepared with C18 cartridges and injected applying Metrohm intelligent Preconcentration Technique (MiPCT). After each injection, the preconcentration column requires additional rinsing to eliminate matrix effects. For this purpose, no other instrument than an 800 Dosino is required. The system is optimized for sample volumes between 20 and 2000 µL. For most samples additional rinsing of the preconcentration column is not required.

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 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.

The commercialization of Li-ion batteries in 1991 was the culmination of in-depth R&D conducted by scientists and engineers around the globe over the preceding few decades. Further development of Li-ion batteries and alternative rechargeable batteries has continued until today. As the world is rapidly moving towards a new era defined by green technologies, more practical and accurate R&D is required in order to meet the increasing demands for energy storage systems, specifically from the automotive industry. This white paper presents the basics of the Li-ion battery technology and guides the reader through the relevant techniques and terminologies in Li-ion battery research.

In battery research, electrochemical impedance spectroscopy (EIS) is a necessary tool to investigate the processes occurring at the electrodes. With a common three-electrode battery, EIS can be performed sequentially first at one electrode and then at the other electrode.

Determination of ammonium, magnesium, and calcium in a fertilizer using cation chromatography with directconductivity detection.

Determination of ammonium, potassium, magnesium, and calcium in a liquid fertilizer using cation chromatography with direct conductivity detection..

1,3,5-trioxane is a heterocyclic compound formed by trimerization of formaldehyde. Trioxane is used for the production of polyformaldehyde plastics such as poly(oxymethylene) (POM) and solid fuels. Aqueous 1,3,5-trioxane solutions frequently contain trace triethylamine that requires quantification. This is performed on the Metrosep C 3 - 250/4.0 column with subsequent direct conductivity detection.

Calcium carbonate has a wide applicability in the pharmaceutical industry as an excipient and also as an active ingredient, and in the food industry as a major dietary supplement. The U.S. Pharmacopoeia (USP) monographs for calcium and magnesium carbonates tablets as well as calcium carbonate and magnesia chewable tablets currently describe manual titration as the assay procedure for calcium and magnesium. The USP has embarked on a global initiative to modernize many of the existing monographs across all compendia. In response to this initiative, two alternative analytical methods were developed to determine the analytes calcium and magnesium. This Application Note presents ion chromatography (IC) procedures using conductivity detection that provide better accuracy and specificity and are suitable for the intended purpose. These validated IC methods (according to USP General Chapter <1225>) offer a significant improvement to the existing assays because they can simultaneously determine both analytes calcium and magnesium, saving both time and effort.

Compounded injections of sodium bicarbonate are sterile solutions for correcting metabolic acidosis and other conditions requiring systemic alkalinization. Compounded injections of sodium phosphates serve as a phosphate source to either prevent or correct hypophosphatemia in patients with restricted oral intake. Ion chromatography (IC) with suppressed conductivity detection is the standardized way to accurately quantify sodium in these solutions.

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.

Determination of fluoride in cement or clinker by direct potentiometry with the F-ISE.

Soluble tungsten and molybdenum are available in soil mainly as their oxosalts, tungstate and molybdate. Tungstate is rather a hazardous compound, which may interfere with plant growth. Molybdate, on the other hand, is a required micronutrient, required e.g. for nitrate fixation in legumes. Both can easily be determined after alkaline digestion with ion chromatography followed by conductivity detection after chemical suppression.

Determination of alkyllead compounds in petrol (gasoline) after reaction with iodine monochloride by potentiometric titration with EDTA using the Cu-ISE.

This Application Note describes the photometric determination of aluminum in cement using the Optrode (574 nm). Following breakdown of the cement sample, the dissolved aluminum is titrated with EDTA. The excess EDTA is titrated back with zinc sulfate solution.

For titrations in low conducting media (e.g., non-aqueous titrations) the potentiometric indication can be disturbed by interfering signals. When differential amplification is used, these signals are measured by both the measuring electrode and the reference electrode and thus neutralized. It is therefore possible to obtain smoother titration curves and more reproducible results.This Application Note describes the potentiometric determination of the acid number and base number in used motor oil by the differential amplification using a fully automated OMNIS system.

Determination of Cd, Pb, and Cu in brine and NaOH.

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).

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.

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.

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.

Electrochemical measurements utilizing a rotating cylinder electrode (RCE) are widely used in industrial corrosion applications when simulation of realistic pipe conditions are necessary in a lab environment. This white paper allows further insight into the particularities and parameters which govern the electrochemical measurements, in particular measurements performed in turbulent flow conditions, and shows a complete picture of the best practice use of this technique. The annexes provide an overview and short explanation of the parameters and laws specific to the fluid behavior in electrochemical cells with RCE.

In routine chemical analysis, the predominant challenge involves a higher sample throughput, improved reproducibility, liquid handling flexibility and reduced personnel costs. In response to these requirements, the 872 Extension Module Liquid Handling in combination with the MagIC NetTM software and the well-proven Dosino technology expands the possibilities of inline sample preparation and opens up new fields of application. Among others, the module can be used, together with an optional mixing vessel, for pH adjustments, pre-column derivatizations, or the mixing of solutions.As a representative of an inline sample preparation technique, this poster describes the performance of precise dilutions. By using only one single stable standard solution, multi-point calibration curves can be automatically recorded by diluting a concentrated standard in an external vessel.

Determination of calcium and magnesium in high-purity sodium chloride using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, and potassium in polyethers using cation chromatography with direct conductivity detection.

Determination of sodium and potassium in toothpaste using cation chromatography with direct conductivity detection.

Thermometric titration quickly and accurately assesses the total solids content of fluids employed in drilling oil and gas wells within minutes.

Determination of sodium lauryl ether sulfate surfactants.

This Application Note describes the determination of the total concentration of sodium in precursor solutions used in the manufacturing of margarine. The solutions of the precursors are mixed with edible fats and oils to make margarine. Traces of sodium chloride and other sodium and potassium salts may be added to the margarine during this process, usually in the form of emulsifiers, stabilizers, antioxidants, vitamins, coloring agents or flavor enhancers. The analysis of the total sodium content in the precursor solutions is more efficient and cost-effective for the manufacturers than later total sodium content analyses in the final product.As a rule, argentometric titration of chloride is used for indirect determination of the sodium content of foodstuffs. The assumption behind this approach is that the chloride ions are present in a molar ratio of 1:1 with the sodium ions. This is however not the case when – as is usually the case with foodstuffs containing sodium – additional compounds containing sodium are also present in the margarine. The use of potassium chloride as a partial replacement for sodium chloride in some formulations is an additional source of error.The direct titration of sodium by means of thermometric endpoint titration (TET) eliminates these problems. TET is a direct determination method that not only takes into account the entire sodium content present in the solution but is also not hampered by the presence of potassium ions. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

About 20% of our sugar comes from sugar beet crops, mostly grown in Europe and the U.S. where the climate is temperate, whereas the other 80% is produced from sugar cane in tropical areas. Lime salts and pH are very important factors which are controlled during the sugar manufacturing process. Complexometric titration is often used to determine the concentration of lime salts in such kinds of samples. This Application Note presents a more robust method for determining calcium compounds in sugar beet juice. Subjectivity of color change determination is eliminated by using an ion selective electrode (ISE).

Hexavalent chromium (chromate) in soil needs to be minimized as it acts cancerogenic. Chromate may be introduced to soil by applying fertilizers containing Cr(VI). Most of this chromate is reduced to Cr(III) by oxidizing organic matter. The remaining chromate is determined according to EN ISO 15192 by alkaline digestion followed by ion chromatography with post-column reaction with 1,5-diphenylcarbazide and subsequent visible detection at 538 nm. Procedure B of EN 16318 applies the alkaline digestion and the same analytical procedure to fertilizers.

Determination of Zn, Cd, Pb, and Cu in whiskey after UV digestion.

Determination of cadmium and lead in herbicide powder containing 37% copper after digestion.

Determination of W(VI) in the organic phase after digestion

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

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.

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 concentration of Fe is determined polarographically in phosphoric acid. The method is suitable for iron in concentrations in the ppm range. Fe(II) and Fe(III) show signals with the same sensitivity

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

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

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.

This Application Note describes the polarographic determination of indium 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 the molybdenum-coated substrate. Indium analysis is carried out after dilution of the bath sample with sulfuric acid as supporting electrolyte.

This white paper summarizes the steps involved in converting an existing manual titration procedure to semi-automated or automated titration procedures. It discusses topics such as selecting the right electrode and titration mode. For a better understanding, the discussion topics are illustrated with three examples.

This poster presented jointly with USP at AAPS meeting shows, that we successfully developed and validated a single IC procedure for potassium assay and identification in potassium bicarbonate and potassium chloride for effervescent oral suspension. The optimized chromatographic conditions could be used for other cationic impurities, such as magnesium, calcium, sodium, and ammonium in potassium bicarbonate and potassium chloride for effervescent oral suspension. Single chromatographic method for assay and identification simplifies the overall QA/QC workflow.

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).

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.

Within the scope of the USP monograph modernization, sodium is determined in potassium sodium tartrate applying cation chromatography with direct conductivity detection. The USP41 monograph for «Potassium sodium tartrate» does not yet mention an assay for sodium. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). The assay of potassium is performed with two commercially available products according to USP definitions. All acceptance criteria are fulfilled. See AN-C-182 for the respective determination of potassium. Apllying this method allows to determine sodium and potassium simultaneously according to USP.

Determination of calcium and magnesium in process solutions.

Determination of nitrate, sulfate, and thiocyanate in additives for building materials using anion chromatography with direct conductometric detection.

Determination of chromate using anion chromatography with post-column reaction and UV/VIS detection.

Determination of molybdate in 2.5% NaCl using anion chromatography with conductivity detection after chemical suppression and inline matrix elimination by molybdate preconcentration after the first separation and subsequent reinjection.

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.

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.

This poster presented jointly with USP at AAPS meeting shows the new USP method for zinc as per <591> using Ion Chromatography which is highly selective and sensitive. Selectivity is achieved by separation and further improved with PCR reaction. Sensitivity and wide linear quantification limit make the new USP method ideal for QA/QC. Automated PCR delivery makes the overall method performance easy to validate.

Within the scope of the USP monograph modernization, potassium is determined in potassium bitartrate applying cation chromatography with direct conductivity detection. The USP41 monograph for “Potassium bitartrate” does not yet mention an assay for potassium. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). The assay of potassium is performed with two commercially available products according to USP definitions. All acceptance criteria are fulfilled.

Within the scope of the USP monograph modernization, potassium is determined in potassium sodium tartrate applying cation chromatography with direct conductivity detection. The USP41 monograph for “Potassium sodium tartrate” does not yet mention an assay for potassium. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). The assay of potassium is performed with two commercially available products according to USP definitions. All acceptance criteria are fulfilled.

Determination of Na, P, and [Na]/[P] in precursor solutions and solids in the manufacture of sodium tripolyphosphate.

Determination of the potassium content plays a major role in the food and beverage industry. Potassium is an essential mineral nutrient for humans. It is an important intracellular cation and also plays an important role in processes withincells, where it is involved in the regulation of numerous body functions like blood pressure, cell growth and muscle control.To declare the potassium content of drinks and food, it is usually determined by flame photometric method. However, flame photometry is linear only over a limited concentration range, and often sample dilution is necessary. Furthermore, the instrumentation is rather complex and expensive to buy and maintain. The ion measurement method presented here is a fast, less expensive, and reliable alternative to determine potassium content in beverages.

Determination of anions in solder paste after alcoholic extraction using anion chromatography with direct conductivity detection.