Aplicações de cromatografia iônica

The new DIN draft standard 38407-53 outlines TFA analysis in water using direct injection LC-MS/MS, enabling quantification from 0.1–3.0 μg/L as shown in this Application Note.

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.

N-Methylpyrrolidone (NMP) is crucial for lithium-ion battery production. Metrohm’s intelligent Preconcentration Technique with Matrix Elimination enables µg/L-level anion analysis in NMP.

Lithium-ion (Li-ion) battery electrolyte quality is essential for performance, stability, and safety reasons. Ion chromatography is an accurate method for electrolyte analysis.

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 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.

The assay of calcium acetate, often used as a phosphate binder for dialysis patients, can be performed with ion chromatography (IC) as per USP <621> and <1225>.

Potassium citrate and citric acid oral solutions act as systemic alkalizers. Potassium assays, validated per USP <621> and <1225>, use IC with L76 cation-exchange columns.

Substâncias alquílicas per e polifluoradas (PFASs) são milhares de moléculas orgânicas nas quais todos os átomos de hidrogênio em pelo menos um carbono são substituídos por flúor. Os PFASs são amplamente utilizados em diferentes indústrias, por exemplo, como surfactantes para espumas formadoras de filme ou como agentes de impregnação para embalagens. Devido à sua extrema persistência, eles são chamados de «produtos químicos eternos», pois compostos de cadeia mais longa se acumulam no ambiente e se biomagnificam.

Combustion ion chromatography (CIC) measures AOX (adsorbable organically bound halogens, i.e., AOCl, AOBr, AOI) and AOF as well as CIC AOX(Cl) according to DIN 38409-59 and ISO 18127.

Efficiently analyze food products with ion chromatography (IC). Discover its robust applications in quality control for beverages, food additives, and dairy.

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

Differentiation between Cr(III) and Cr(VI) is possible following ISO 24384 guidelines by combining ion chromatography with inductively coupled plasma mass spectrometry.

Organic halides must be monitored in the environment. Combustion ion chromatography (CIC) is used for accurate halogen analysis in solids following EN 17813:2023.

Tris(hydroxymethyl)aminomethane (TRIS) is often used in life science applications and its purity must be monitored. This analysis is possible with ion chromatography.

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

Dental care products often contain sodium fluoride as an active ingredient. Manufacturers use the United States Pharmacopeia and National Formulary (USP-NF) Monograph «Sodium Fluoride» to quantify sodium fluoride and its anionic contaminants chloride and acetate in these products. The validated USP method proposes ion chromatography (IC) with suppressed conductivity detection to carry out the fluoride assay as well as the impurity determination in a single chromatogram.

Ion chromatography (IC) with suppressed conductivity detection has been approved by the U.S. Pharmacopeia (USP) as a validated method to quantify the monofluorophosphate (MFP) content in sodium monofluorophosphate. This Application Note shows that all acceptance criteria for the USP Monograph «Sodium Monofluorophosphate» are fulfilled and the procedure was approved as a validated USP method.

Sodium fluoride tablets for pharmaceutical use need to comply with U.S. Pharmacopeia (USP) requirements. Ion chromatography (IC) with suppressed conductivity detection has been approved by the USP as a validated method to quantify fluoride content in sodium fluoride tablets. In the course of the USP monograph modernization, using automated IC makes this type of analysis even easier.

Sodium fluoride gel for pharmaceutical use needs to comply with USP requirements. The actual monograph (USP 42) uses two different methods for the identification and the assay. Ion chromatography allows the analysis of these two parameters in one single determination. In the course of the USP monograph modernization, this ion chromatographic approach makes this type of analysis even easier.

The USP and FDA started to modernize several monographs and General Chapters. In many cases, IC-focused methods have replaced older, wet chemistry procedures. Learn more about the USP modernization initiative and the advantages of ion chromatography in this white paper.

Nitrosamine formation can be avoided by controlling the nitrite concentration in pharmaceutical products and processes. To monitor nitrosamine formation, sensitive analytical methods such as ion chromatography for the determination of nitrite in pharmaceutical products and substances are essential.

Nitrosamine presence in medicines, even at trace level poses high safety risks to patients (carcinogenic). Nitrosamine formation can be avoided by controlling and monitoring the nitrite concentration in pharmaceutical products and substances. This Application Note describes the analysis of nitrite in duloxetine hydrochloride with ion chromatography (IC).

This White Paper will walk you through the selection process of ion chromatography as the best analytical tool in the product development of a cell-based gene therapy.

Manufacturers and laboratories must use validated methods to determine the zinc content in skin care products and pharmaceutical supplements to meet strict quality standards set by the United States Pharmacopeia and National Formulary (USP-NF). USP-NF has updated the zinc monograph (General Chapter <591>, Zinc Determination) and replaced the existing identification procedure of titration with ion chromatography (IC). The analysis involves separating Zn using a Metrosep A Supp 10 column followed by post-column reaction using 4-(2-pyridylazo)resorcinol and detection at 530 nm.

Within the scope of the USP monograph modernization, potassium and sodium are determined in bicarbonates and citric acid effervescent tablets for oral solution applying cation chromatography with direct conductivity detection. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). All acceptance criteria are fulfilled. The USP41 monograph for “Potassium and sodium bicarbonates and citric acid effervescent tablets for oral solution” performs the assay of potassium by flame photometry.

As an alternative to flame photometry, ion chromatography with non-suppressed conductivity detection has been approved by the USP as a validated method to quantify potassium content in potassium bicarbonate and potassium chloride effervescent tablets for oral solution. The Metrosep C 6 - 150/4.0 column (L76) provides the required separation of potassium and magnesium. The present IC method has been validated according to USP General Chapter <621>.

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.

Within the scope of the USP monograph modernization, potassium is determined in potassium bicarbonate effervescent tablets for oral suspension applying cation chromatography with direct conductivity detection. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). All acceptance criteria are fulfilled.

This White Paper compares automated Inline Ultrafiltration and Inline Dialysis to the traditional Carrez clarification procedure for the analysis of milk samples by ion chromatography (IC). A continuous test series over approximately six months proved Inline Dialysis to be a reliable and valuable alternative to treat dairy products prior to IC analysis.

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.

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

This White Paper focuses on selected IC-MS applications for the straightforward identification and quantification of organic acids and inorganic anions in different matrices.

Anticavity pharmaceuticals like sodium fluoride and acidulated phosphate topical solution products require strict quality control. This Application Note outlines the fluoride IC assay as described in the USP Monograph Sodium Fluoride and Acidulated Phosphate Topical Solution.

Iodine is an essential mineral for human health, where it is necessary for e.g., the production of thyroid hormones. The presented method describes the determination of free iodide in milk samples using Metrohm Low Volume Inline Dialysis for automated sample preparation prior to injection into an ion chromatograph (IC) and subsequent amperometric detection in direct current (DC) mode.

In severe cases of cyanide poisoning, sodium nitrite is used along with sodium thiosulfate for treatment. This Application Note describes the nitrite ion chromatography assay with the Metrosep A Supp 4 column and suppressed conductivity detection. This column equivalency study was in cooperation with the USP according to the USP General Chapter <621>.

Lithium-ion batteries (LIBs) are the most common rechargeable options available today. Production of LIBs needs to follow stringent quality standards.

As an alternative to titration, ion chromatography (IC) with suppressed conductivity detection has been approved by USP as validated method to quantify chloride content in NaCl tablets for solution or oral use.

An ion chromatography (IC) assay with suppressed conductivity detection is the standardized way to accurately quantify phosphate in phosphates compounded injections.

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

This white paper presents IC-MS as powerful analysis technique. This multiparameter method determines various analytes such as inorganic cations and amines in one run.

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

Safe drinking water is essential for human life and is also quite often a privilege. Whether the source is surface or groundwater, the presence of pathogenic bacteria, poor taste, and a detectable odor requires disinfection processes to guarantee the appropriate quality for drinking water purposes.

The short Metrosep C Supp 2 - 100/4.0 allows applying a higher eluent flow. Together with a more concentrated eluent (7.0 instead of 5.0 mmol/L nitric acid) the run time of the four cations, sodium, potassium, magnesium, and calcium can be reduced to 5 minutes. Conductivity detection after sequential suppression is applied.

Cation analysis by IC in wastewater is a proven method. Limiting factor is often the Na/NH4 separation. High sodium concentrations may make ammonium determination impossible due to peak overlapping. The use of sequential suppression and a Dose-in gradient improve the Na/NH4 separation and enables determination of low ammonium concentrations.

Acidic solutions used as scrubber solutions for ammonium typically have a pH of 2 or lower. This pH value is too low for silica based IC columns typically applied in direct conductivity detection of cations. The Metrosep C Supp 2 - 250/4.0 is polymer based and allows injecting low pH samples. An acidified drinking water sample spiked with ammonium is analyzed. The results indicate that such acidic solutions can be analyzed with conductivity detection after sequential cation suppression.

The Metrosep C Supp 2 column family is polystyrene/divinylbenzene based and therefore sequential cation suppression may be applied. This AN shows the separation and detection of different amines on the 150 mm version of the column with subsequent conductivity detection after sequential cation suppression.

Succinylcholine is a short-term paralyzing agent used e.g., for tracheal intubation. Choline is a building block of the drug and needs to be determined as an impurity. USP applies cation chromatography with conductivity detection after suppression. Eluent composition and column type do not exactly comply with the USP method. However, the results fulfill the respective requirements. The choline concentration of the sample is out of USP specifications.

Biogenic amines are released during the winemaking process. In wine, they are present as odorless salts. However, in the mouth their flavor is partially liberated, influencing the appearance for the wine taste. Besides this, biogenic amines have been related to lack of hygiene or poor manufacturing practices. The biogenic amines are determined applying suppressed cation chromatography.

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.

Hydrogen peroxide is available in different purity grades depending on its use. High purity H2O2 (electronic grade) requires very low contamination levels, e.g., less than 1 μg/L of trimethylamine (TMA). This application describes the determination of trimethylamine in a high-purity H2O2 solution (30%). Analysis is performed using Inline Preconcentration with Matrix Elimination (MiPCT-ME) applying conductivity detection after sequential cation suppression.

Lithium hexafluorophosphate (LiPF6) is used as an electrolyte in rechargeable batteries. Its high solubility in non-polar solvents and its non-coordinating character in particular make lithium hexafluorophosphate the ideal salt for use in lithium-ion cells. This Application describes the determination of cation traces in LiPF6 with conductivity detection following sequential suppression.

Boiler feed water is a working medium in thermal power plant. To keep corrosion low, the pH value should be in the slightly alkali range, which is why amines are added to the feed water. This addition must be monitored regularly. Also important is the monitoring of the sodium concentration, because an increase of this indicates that cooling water is seeping into the condenser. Ion chromatography with conductivity detection following sequential suppression is the optimum system for monitoring, particularly in combination with intelligent Sample Preconcentration and Matrix Elimination.

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.

Meropenem is a beta-lactam antibiotic that is classed among the carbapenems; it suppresses murein biosynthesis and thus the buildup of the bacterial cell wall. Dimethylamine is an important precursor in meropenem synthesis and must therefore be monitored as an impurity. Detection is performed on the Metrosep C Supp 1 - 250/4 column with subsequent conductivity detection after sequential suppression.

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

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.

Atorvastatin is a medication that is used for reducing cholesterol levels. A sensitive and reliable method for TBA detection is required, given that trace amounts of tetrabutylammonium (TBA) are to be found in the presence of atorvastatin and its derivatives. One such method is ion chromatographic separation on the Metrosep C Supp 1 - 250/4.0 with subsequent conductivity detection and sequential suppression.

Choline is important for the biosynthesis of numerous molecules, e.g., the neurotransmitter acetylcholine, and exists as an intermediate product in the human metabolism. Concentration determination takes place after microwave digestion. Separation is performed on the Metrosep C Supp 1 - 250/4.0 column following sequential suppression. Separation from the standard cations is outstanding.

The concentrations of toxic, biogenic amines in foods, particularly in fish and wine, are an important quality characteristic. The present Application Note shows the separation of putrescine, cadaverine and histamine in addition to the standard cations. Separation takes place on a Metrosep C Supp 1 - 250/4.0 with Dose-in Gradient; quantification via conductivity detection following sequential suppression.

Ammonium determination after sequential suppression frequently exhibits non-linear calibration curves. The reason for this is the ammonium hydroxide that arises and that is present in a form characterized by low dissociation. The sequential cation suppression forms the more highly dissociated ammonium hydrogen carbonate. Ammonium and the other standard cations exhibit linear calibration curves (R > 0.9997).

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.

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

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

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.

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

Neutralizing amines are added to adjust pH levels within the water-steam circuit of power plants to avoid corrosion-inducing conditions. This preventive maintenance can reduce costly and critical downtimes due to corrosion, however frequent monitoring of the amine chemistry is necessary to ensure conditions stay optimal. The 2060 IC Process Analyzer featuring the Metrohm intelligent Partial Loop Technique (MiPT) option is ideal for this application, with the ability to measure trace amounts of the analytes precisely and reliably through an automated method. The benefit of using IC is that multiple analytes can be monitored simultaneously, and here the ability to measure the presence of sodium next to the high ammonium or amine concentrations could indicate that cooling water is seeping into the circuit, indicating a problem upstream.

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

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.

Hexavalent chromium (Cr(VI)) is regarded as being toxic and potentially carcinogenic. Its concentration in drinking water should therefore be kept as low as possible. The determination of Cr(VI) is performed using ion chromatography. The separation takes place on the Metrosep A Supp 10 - 250/2.0 separation column. The presence of Cr(VI) is determined photometrically following post-column reaction (PCR) with diphenylcarbazide.

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.

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

Determination of cefadroxil in accordance with USP 28-NF 23 (Supplement 2) using RP chromatography with UV detection. Keyword: Antibiotics

Determination of thiamine hydrochloride according to USP 28-NF 23 (second supplement) using RP chromatography with UV detection.

Determination of cefazolin in accordance with USP 28-NF 23 (Appendix 2) using RP chromatography and subsequent UV detection. Keyword: Antibiotics

Determination of bromate in water using anion chromatography with UV/VIS detection after post-column reaction (PCR) with o-dianisidine reagent (described in EPA 317.0).

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.

Aluminum (as gel or salt) is used in vaccines as an adjuvant. This helps to get a stronger immune response. The amount of aluminum in vaccines is regulated e.g., by USP. According to USP maximum amounts of Al3+ in a vaccine dose lay between 0.85 and 1.25 mg. This work describes the determination of aluminum as the 8-hydroxyquinoline complex by ion chromatography with UV/VIS detection.

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

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 determination of amino acid is an important task in pharmaceutical and biochemical applications. A binary gradient separates in this example 17 amino acids of a commercially available standard solution. The post-column reaction with ninhydrin requires a temperature of 120 °C, while the samples need to be cooled for stability.

Determination of aluminum in phosphoric acid using cation chromatography with UV detection after post-column reaction with catechol violet.

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.

Determination of penicillin G potassium and 2-phenyl acetamide in accordance with USP 28-NF 23 (Appendix 2) using RP chromatography and subsequent UV detection. Keyword: Antibiotics

Determination of theophylline and theobromine according to USP 28-NF 23 (second supplement) using RP chromatography with UV detection.

Determination of cloxacillin sodium in accordance with USP 28-NF 23 (Appendix 2) using RP chromatography and subsequent UV detection. Keyword: Antibiotics

Determination of saccharin, benzamide, and o-toluenesulfonamide in a nickel electroplating bath using RP chromatography with UV detection.

Determination of caffeine in a cola soft drink using RP chromatography with UV/VIS detection.

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

Determination of traces of fluoride, bromide, nitrate, phosphate, and sulfate using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection.

Determination of bromide and nitrate in 1% sodium chloride solution using anion chromatography with UV/VIS detection (205 nm) after chemical suppression.

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

Nitrite in tobacco facilitates the release of tobacco-specific nitrosamines. Most of these nitrosamines are carcinogenic. Therefore, the determination of nitrite in tobacco is required. This application describes the determination of nitrite and nitrate in acetic acid extracts of tobacco. The ion chromatographic separation is followed by UV/VIS detection after sequential suppression.

The Benfield Process is a well known procedure to remove H2S and CO2 from petroleum and industrial gases. Vanadium pentoxide is added as a corrosion inhibitor and is most effective in a certain V(IV)/V(V) ratio. Therefore, speciation and determination of V(IV) and V(V) is important. This speciation is easily achieved on A Metrosep A Supp 5 - 50/4.0 column with EDTA as an eluent and UV/VIS detection at 282 nm.

Paracetamol is an effective antipyretic and analgesic. Its determination in tablets using reverse phase chromatography and UV detection is quick and easy with the sample preparation described in this Note. The 815 Robotic Soli Prep for LC does everything automatically: from dissolving the tablets, homogenizing and filtering, to 250-nL-Loop injection.

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.

Complexing agents are used in fertilizers to bind trace nutrients such as cobalt, iron, manganese, etc. EN 13368-1 describes the determination of EDTA, HEDTA, and DTPA. As sample preparation, Fe3+ is added to build complexes with the three agents. The complexes are separated on an anion-exchange column and detected by UV/VIS after addition of perchloric acid.

Potassium bromate is used as a flour improver. The determination of the carcinogen bromate in flour requires extraction and additional sample preparation. In this application, Inline Dialysis is used after sonication and centrifugation of the extraction mixture. Bromate is detected by conductivity following suppression and UV/VIS detection and post-column reaction.

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

Hexavalent chromium (chromate) is known to be carcinogenic if inhaled, and suspected to be carcinogenic if ingested. EPA Method 218.7 allows to determine chromate in drinking water down to the sub-µg/L range (method detection limit, MDL = 15 ng/L). Post-column reaction with 1,5-diphenylcarbazide and subsequent visible detection at 530 nm is applied.

Cell culture growth media contain all required components to keep cells alive. Here the amino acid composition is analyzed. A binary gradient separates in this example amino acids. The post-column reaction with ninhydrin requires a temperature of 120 °C, while the samples need to be cooled for stability.

Chromate (Cr(VI)) or hexavalent chromium is carcinogenic. Its use is restricted. Chromate has to be analyzed in a large range of products starting with drinking water, wastewater (e.g., from leather production), over toys to RoHS-regulated substances. Besides ion chromatographic determination applying conductivity detection, the method described here is suitable especially for lower concentrations.

Determination of silicate and hexafluorosilicate (calculated) using anion chromatography with conductivity detection after chemical suppression (see AN S-277) and subsequent UV/VIS detection with post-column reaction. Hexafluorosilicate is hydrolyzed into fluoride and silicate. Both anion concentrations may be used for the calculation of the SiF62- concentration.

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

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

Determination of melamine in milk, diary products, eggs, and egg-based foodstuffs using cation chromatography.

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

Determination of sulfide in mining wastewater using anion chromatography with UV detection.

Determination of ranitidine hydrochloride according to USP 28-NF 23 (second supplement) using RP chromatography with UV detection.

Determination of valerophenone and ibuprofen according to USP 28-NF 23 (second supplement) using RP chromatography with UV detection.

Determination of sulfide in a raw vanadate solution using anion chromatography with UV/VIS detection.

Determination of amoxicillin in accordance with USP 28-NF 23 (Appendix 2) using RP chromatography and subsequent UV detection. Keyword: Antibiotics

Determination of salicylic acid and acetylsalicylic acid according to USP 28-NF 23 (second supplement) using RP chromatography with UV detection.

Determination of phenylalanine, aspartame, caffeine, and benzoate in a soft drink using RP chromatography with UV detection.

Determination of vanadium(IV) and vanadium(V) in Benfield solution using anion chromatography with UV detection.

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

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.

Determination of HEDPA, PBTC, and NTP using anion chromatography with UV/VIS detection after post column reaction (PCR).

Determination of N-acetylcysteine and phenylalanine in tablets against sinusitis by anion chromatography with UV/VIS detection according to USP.

Determination of iodate, chlorite, bromate, and nitrite using suppressed anion chromatography with UV/VIS detection after post-column reaction.

Determination of glycolic and lactic acid in the presence of N-methyl pyrrolidone used in drug delivery systems using ion-exclusion chromatography with UV/VIS detection.

Determination of nickel, zinc, iron(II), and manganese in lithium bromide using cation chromatography with UV/VIS detection (520 nm) after post-column reaction.

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

The determination of iodate and iodide in used electroplating baths is a demanding task due to the high concentration of other ions. Iodate is used as a stabilizer for the bath and needs to be checked for proper electroplating. The use of a sodium chloride eluent, the Metrosep A Supp 5 - 250/4.0 column and direct UV/VIS detection permits the analysis of these samples without matrix interferences.

Seawater analysis with conductivity detection is difficult due to the high excess of chloride. Especially analyzing for nitrite and bromide, UV/VIS detection is preferred as chloride is not interfering with nitrite at 218 nm. This AN shows the determination of all three UV-absorbing anions in an artificial seawater.

Determination of nitrite and nitrate in a cooling lubricant using anion chromatography with conductivity detection (see AN S-274) and subsequent UV detection after sequential suppression and Metrohm Inline Dialysis.

The determination of PBBE (tetrabromobisphenol A - TBBPA, octabromodiphenyl ether - OCTA and decabromodiphenyl ether - DECA) in a polymer sample was carried out with the Nucleosil EC - 250 mm column; for this purpose a methanol and phosphate buffer was used as an eluent and subjected to UV detection in accordance with the IEC 62321 method for RoHS testing.

Determination of sulfide and thiosulfate in a process water using anion chromatography with UV/VIS detection after chemical suppression and conductivity detection.

Determination of nitrite, bromide, nitrate, and iodide in 10 g/L sodium chloride using anion chromatography with UV detection.

Determination of bromide in calcium chloride using anion chromatography with UV/VIS detection.

Monitoring the range of organic acids in wine is crucial to improve flavor and quality, and to fulfill universal standardized criteria such as the International Code of Oenological Practices. Analytically, organic acids can be properly determined with ion chromatography (IC) and suppressed conductivity detection. As a multicomponent method, inorganic acids can also be resolved which are also valuable tracers for wine quality and taste. This Application Note presents two IC methods for wine quality analysis: a fast isocratic screening method of major organic acids and anions including sulfite, and a complex monitoring method with a binary gradient to separate 15 organic acids. Inline Ultrafiltration was used for economical sample treatment.

Forensic institutes examine terrorist attacks and warfare agents via trace detection analysis of the used explosives and their residuals. Of particular importance is the acquisition of «chemical fingerprints» for criminal investigation departments and governmental security agencies. Institutes for public health and environmental protection analyze such compounds that can contaminate the underlying soil and infiltrate ground water. Forensic investigation with ion chromatography (IC) using suppressed conductivity detection allows a sensitive and robust determination of anionic contaminants such as chlorate, thiosulfate, thiocyanate, and perchlorate next to the common inorganic anions over a broad concentration range.

In the course of USP column equivalency tests, the Metrosep A Supp 3 - 250/4.0 is applied for the assay of citric acid/citrate and phosphate according to USP general Chapter <345>. This report shows that the Metrosep A Supp 3 - 250/4.0 column is equivalent to packing L61 required in USP general Chapter <345>.

EN ISO 10304-1 is one of the most important standards for the determination of the seven standard anions in water samples. Many other standards refer to EN ISO 10304-01 if anion determination by IC is required. This standard asks for a membrane filtration for samples to avoid bacteria and solids, if required. This application shows the determination of anions according EN ISO 10304-1 applying Inline Ultrafiltration. This setup avoids tedious manual sample filtration and handles any samples fully automatically.

Monoethylene glycol is used for dehydration of the natural gas before liquefaction and has to be checked for its purity on routine basis. Inorganic anions and their corresponding acids are corrosive. Therefore, they have to be kept at minimum level. The separation is performed on a microbore Metrosep A Supp 16 - 250/2.0 column and quantified by conductivity detection after sequential suppression.

Microbore columns with an inner diameter of 2 mm reduce the eluent consumption to about a quarter. Consequently, the detected peak areas of corresponding sample concentration are increased by a factor 4. In this report, the determination of anions in drinking water is described on a Metrosep A Supp 5 - 150/2.0 column.

Traces of organic acids can be determined only with difficulty in the presence of high concentrations of standard anions, because their small peaks generally disappear under the larger peaks of the standard anions. A simple dose-in-gradient improves the separation: acetate and formate are baseline-separated from fluoride. Furthermore, oxalate elutes considerably less than sulfate. The separation takes place on a column of the Metrosep A Supp 7 - 250/4.0 type with subsequent conductivity detection following sequential suppression.

The column stability of the microbore version of the Metrosep A Supp 5 - 250/2.0 was determined in long-term laboratory tests. Two injection series each were run on six days in a row. Each series was comprised of nine tap water injections, three check standard injections and six tap water injections. The IC system was shut down on the seventh day of each series. As a whole, the IC system ran over 12 weeks and counted a total of 2,650 injections. The results show an outstanding reproducibility and verify the high column stability.

Special brighteners are used in electroplating baths in order to provide the refined surfaces with greater brightness. The concentration of brighteners must be kept constant at all times in order to ensure uniform end product quality. This Application Note describes how brighteners are determined in parallel with IC and CVS. The corresponding CVS application can be found under AN-V-183.

Azide may be formed during the production of certain pharmaceutical products. It can cause explosions during manufacturing. Therefore, its concentration in the air needs to be monitored in order to prevent such accidents. Azide (N3-) is well separated from standard anions on the Metrosep A Supp 5 - 250/4.0 under standard conditions.

Nadroparin is a low-molecular-weight heparin used as a anticoagulant to prevent thrombosis. The determination of sulfate in the sulfur-containing anticoagulant is performed to control the degradation of the product. Thanks to the absence of interfering peaks close to sulfate, a short column could be used.

Determination of fluoride, chloride, bromide, and iodide in petroleum coke after microwave combustion using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, acetate, formate, chloride, sulfate, malonate, succinate, and oxalate in Bayer liquor using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, acetate, formate, nitrate, and sulfate in a gasoline/bioethanol mixture (85% gasoline, 15% ethanol) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Matrix Elimination.

Determination of fluoride, chloride, nitrate, sulfate, and oxalate in a perfluorocarbon material using anion chromatography with conductivity detection after chemical suppression.

Determination of thiooctanoate in wastewater using anion chromatography with conductivity detection after chemical suppression.

Determination of sulfate in an ethanol sample used as an additive for gasoline using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride in bethanechol tablets using anion chromatography with conductivity detection after chemical suppression.

Determination of 21 anions and organic acids using anion chromatography with conductivity detection after chemical suppression and applying a high pressure gradient.

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

Determination of fluoride, chloride, bromide, nitrate, sulfate, and trifluoroacetate (TFA) in a peptide sample using anion chromatography with conductivity detection after chemical suppression.

Determination of citrate, dipolyphosphate, and tripolyphosphate in a food additive using anion chromatography with conductivity detection after chemical suppression.

Determination of acetate, chloride, and sulfate in mayonnaise using anion chromatography with conductivity detection after chemical suppression and inline sample preparation by dialysis.

Determination of chloride, bromide, nitrate, sulfite, sulfate, oxalate, and thiosulfate in a process water of the paper industry using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, nitrite, cyanate, azide, nitrate, chlorate, sulfate, thiocyanate, thiosulfate, and perchlorate in an extract of explosives using anion chromatography with conductivity detection after chemical suppression.

Determination of sulfite, oxalate, thiosulfate, and thiocyanate in the presence of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate using anion chromatography with a high pressure gradient and conductivity detection after chemical suppression.

Determination of fluoride, chloride, nitrite, nitrate, benzoate, and sulfate in PVC film using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, glycolate, chloride, and oxalate in a latex dispersion using anion chromatography with conductivity detection after chemical suppression and dialysis for sample preparation.

Determination of sulfate in methansulfonic acid (70%) using anion chromatography with conductivity detection after chemical suppression.

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

Determination of sulfite in ginger powder using anion chromatography with conductivity detection after chemical suppression and dialysis for sample preparation.

Determination of fluoride, chloride, bromide, sulfate, and iodide in mineral extracts using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, chlorate, and sulfate in soda lye (NaOH 50%) after inline neutralization using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, nitrate, phosphate, and sulfate in boric acid with sample preconcentration using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, bromide, nitrate, sulfate, and iodide in rock leachant using anion chromatography with conductivity detection after chemical suppression.

Determination of traces of chloride in a technical product using anion chromatography with conductivity detection after chemical suppression.

Separation of fluoride, chloride, nitrite, bromide, nitrate, phosphate, phosphite, sulfate, and tetrafluoroborate using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, bromide, and sulfate in synthetic seawater using anion chromatography with conductivity detection after chemical suppression.

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

Analysis of sodium hydrogen carbonate (also known as sodium bicarbonate) for anionic contaminants is critical due the large amount of CO2 formed during suppression. Even applying sequential suppression does not completely remove the interferences due to the carbonate peak. The introduction of Inline Neutralization applying the Sample Preparation Module (SPM) with subsequent CO2 removal with the MCS (Metrohm CO2 Suppressor) prior to the injection solves the problem. After this pretreatment, the sequentially suppressed sample is analyzed without issues.

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.

Sodium fluoride and phosphoric acid gel for pharmaceutical use need to comply with USP requirements. The actual monograph (USP 42) uses two different methods for the identification and the assay. Ion chromatography allows the measurement of these two parameters within a single determination. In the course of the USP monograph modernization, this ion chromatographic approach makes this type of analysis even easier.

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.

ASTM D8234 describes the determination of anions in high saline water by applying suppressed conductivity followed by UV/VIS detection. This combination enables the determination of e.g. nitrite by UV detection. With conductivity detection, this quantification is not possible or difficult due to the very large chloride peak. The actual sample is a refining process liquid with a high chloride content. As the sample solution also contains organic material, Inline Dialysis is applied to protect the analytical column. The combination of the two detection modes and the Inline Dialysis option reduces manual sample preparation and substantially increases the accuracy of the analysis.

Fluoride is commonly used in dental products to help prevent tooth decay. If the products are intended to prevent the formation of cavities (carries), then it is regulated by the US Food and Drug Administration (USFDA) as an Over-the-Counter (OTC) Drug. Previously, the assay of Fluoride in oral solution was done by Ion selective electrode and identification was done by tedious wet chemistry method. USP has updated this monograph for Assay and identification tests with Ion Chromatography using L46 packing. The Metrosep A Supp 1 - 250/4.6 column fulfills all USP acceptance criteria. It therefore is a viable alternative separation column for the determination of sodium fluoride in oral solutions.

Within the scope of the modernization of USP, chloride and sulfate are determined as impurities in potassium hydrogen carbonate (bicarbonate). USP41 monograph for potassium bicarbonate does not check for chloride and sulfate. Applying ion chromatography with conductivity detection after sequential suppression allows quantifying these impurities.

Determination of arsenic in dust from a waste incineration plant is performed. This is required as the environmental risk depends on the degree of oxidation of the arsenic species. Due to the different pKa of the respective anions, selenite requires non-suppressed conductivity detection, while arsenate is best determined with suppression. The determination of both species is achieved by switching the suppressor in and out, respectively.

Organic acids in wine are omnipresent in winemaking. Some of them are present already in the grape while others appear during fermentation. The sum of organic acids and their composition have a direct influence on the taste of the respective wine. In this application a wine is tested for minor organic acids, especially shikimic and iso-citric, besides typical acids and anions. The separation is performed by anion chromatography applying a low-pressure gradient to achieve the required selectivity.

Kjeldahl nitrogen is a typical titration application that follows digestion and ammonia distillation. The ASTM Standard D8001 now offers an alternative applying persulfate digestion followed by IC determination. No distillation is required. In addition, the method enables the determination of total nitrogen and total phosphorus. We show the results of control samples containing organic substances. As these substances are dissolved in ultrapure water, the nitrogen concentration found corresponds to Total Nitrogen and Kjeldahl Nitrogen.

Parallel anion and cation analysis is typically used when both anions and cation have to be analyzed. Here, the anion part of such an analysis is shown. The sample is injected to the anion channel from the 889 IC Sample Center by its built-in injector. The whole system is controlled by Empower applying the Metrohm IC Driver 2.0. For cation analysis, see AN-C-166.

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.

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.

Inline Ultrafiltration is a proven sample preparation technique for samples that are slightly or massively contaminated with particles, algae or bacteria. Filtration and injection are coupled and fully automatic. As a rule, 100 or more samples can be filtered through a single membrane. Service life is extended – even with highly contaminated tannery effluent – to more than 300 injections because the filter membrane is rinsed again once more after the analysis with the aid of the Dosino backflush.

Retention of thiosulfate, thiocyanate and perchlorate is strong on the Metrosep A Supp 5 - 250/2.0 column. A shorter run time for the separation of the anions mentioned along with standard anions is achieved using a low-pressure gradient.

Sodium metabisulfite, also known as pyrosulfite, is used as a preservative and antioxidant in pharmaceutical products. Metabisulfite is not stable in aqueous solutions and quickly converts to sulfite. The peak in the chromatogram originates from the sulfite. This process is however calibrated using metabisulfite standard solutions, which is why the results are specified as sodium metabisulfite. This Application Note describes the determination of metabisulfite as sulfite in an ointment. It is dissolved in an aqueous solution containing formaldehyde to protect the sulfite against oxidation.

Swimming pool water needs to be thoroughly disinfected and this is often accomplished with ozonization. This process can generate harmful oxyhalides, the concentration of which must be monitored. Here the separation and determination of oxyhalides as well as standard anions are carried out using a column of the Metrosep A Supp 5 - 250/4.0 type. Quantification takes place using conductivity detection in accordance with sequential suppression.

Fast IC means short run times and a high sample throughput. This is attained using short columns and strong eluents. Fluoride, chloride, nitrate, phosphate, sulfate and oxalate are separated in less than eight minutes using the Metrosep A Supp 5 - 100/4.0.

Fast IC means a high sample throughput. This is attained with short columns, relatively high flows and strong eluents. Here standard anions are determined within three minutes on the Metrosep A Supp 10 - 50/4.0.

The determination of orthophosphate and polyphosphates is an important quality control for shrimp. The Dose-in Gradient setup accelerates phosphate separation by adding a stronger eluent. The separation of the phosphates is achieved by increasing the carbonate concentration while maintaining the same hydroxide content.

Formate, acetate, propionate, and butyrate in addition to standard anions are determined in a coal extract. To improve the separation of the early eluting organic acid anions, a Dose-in Gradient is applied. Due to the limited sample volume available, Metrohm intelligent Pick-up Technique (MiPuT) is also utilized.

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 determination of anions in tap water is a simple IC application. Here it is used to present Metrohm's intelligent Pick-up Technique (MiPuT). MiPuT enables the injection of volumes of minimum size from very small sample quantities. In the present case, two volumes of 10 µL from a sample 100 µL in size are used for anion and cation analysis, respectively. The calibration takes place through the injection of various volumes of a single standard solution. AN-C-141 describes the corresponding cation determination.

The anion column Metrosep A Supp 15 - 150/4.0 is a pretty high-capacity column. The direct determination of arsenate in a matrix of 180 mg/L chloride and 320 mg/L sulfate is not possible, as the arsenate is hardly detectable under the sulfate peak tail. Sample reinjection cuts off the majority of the matrix and therefore allows an accurate determination of the arsenate.

Whitening toothpaste often contains polyphosphates to remove stains. The analysis of these polyphosphates requires a high-pH hydroxide eluent. The high eluent concentration is suppressed by the high-capacity suppressor MSM-HC.

Topiramate is an antiepilepsy drug. According to USP Topiramate tablets have to be tested for impurities. The determination of sulfate and sulfamate is mentioned under 'Specific Tests'. The isocratic method applies a column eluent combination primarily used for non-suppressed IC. But as sulfamate shows a negative peak under theses conditions the use of suppression is advantageous.

Determination of phosphate, HEDP (etidronic acid), and pyrophosphate in a biocide sample using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, chloride, phosphate, and sulfate in sodium tetraborate using anion chromatography with conductivity detection after sequential suppression. Inline acidification is applied to convert tetraborate into boric acid which is not retained on the preconcentration column. Inline calibration minimizes the anion contamination.

Determination of chloride, nitrite, bromide, nitrate, phosphate, sulfite, sulfate, and oxalate in a cooling lubricant using anion chromatography with conductivity detection and subsequent UV detection (see AN-U-047) after sequential suppression and Metrohm Inline Dialysis.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate, and sulfate impurities in syringe filters using anion chromatography with conductivity detection after sequential suppression.