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Determination of bromate in mineral water 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 phosphite in the presence of chloride, nitrate, bromide, nitrate, and sulfate in a potato extract using anion chromatography with conductivity detection after chemical suppression and inline sample preparation by dialysis.

Determination of nitrite and nitrate in a plant extract using anion chromatography with conductivity detection after chemical suppression.

Determination of iodide in a table salt using anion chromatography with conductivity detection after chemical suppression.

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

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

Determination of chloride, sulfite, sulfate, oxalate, and thiosulfate in lignin 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 sulfate, phosphate, citrate, pyrophosphate, trimetaphosphate, and tripolyphosphate in a washing powder using anion chromatography with conductivity detection after chemical suppression.

Determination of traces of chloride in a quaternary ammonium hydroxide using anion chromatography with conductivity detection after chemical suppression and inline cation exchange to remove the matrix cations.

Determination of bromide, sulfite, sulfate, and thiosulfate in a photographic developer solution using anion chromatography with conductivity detection after chemical suppression.

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

Determination of fluoride, chloride, and sulfate in an absorption solution containing H2O2 using anion chromatography with conductivity detection after chemical suppression.

Determination of phosphoric acid in a soft drink using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate, and sulfate in wastewater containing N-methylpyrrolidone using anion chromatography with conductivity detection after chemical suppression and inline matrix elimination.

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 chloride in a child's sweat using anion chromatography with conductivity detection after chemical suppression.

Determination of citrate and isocitrate in orange juice using anion chromatography with conductivity detection after chemical suppression and inline dialysis for sample preparation.

Determination of chloride, nitrite, nitrate, phosphate, and sulfate in a strongly alkaline solution using anion chromatography with conductivity detection after chemical suppression.

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

Determination of fluoride, nitrate, phosphate, sulfite, and sulfate in an etching bath using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, phosphate, and sulfate in beer wort using anion chromatography with conductivity detection after chemical suppression.

Determination of iodide in a human 24 hour urine sample using anion chromatography with amperometric detection after chemical suppression. The result agrees with that of the photometric method. UV detection did not work.

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, and sulfate in water from an agricultural irrigation system using anion chromatography with conductivity detection after chemical suppression.

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

Determination of fluoride, acetate, formate, and chloride in a brake fluid using anion chromatography with conductivity detection after chemical suppression.

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

Determination of sulfate, molybdate, and chromate in a plating bath using anion chromatography with conductivity detection after chemical suppression.

Determination of formate, chloride, nitrite, phosphite, phosphate, sulfite, nitrate, and sulfate using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride and bromide in an absorption solution after Wickbold digestion using anion chromatographywith conductivity detection after chemical suppression.

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

Determination of nitrate and sulfate in a fertilizer after acid digestion using anion chromatography with conductivity detection after chemical suppression.

Determination of traces of perchlorate in a sample with a high salt load using anion chromatography with conductivity detection after chemical suppression.

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

Determination of nitrate and phosphate in a liquid fertilizer using anion chromatography with conductivity detection after chemical suppression.

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

Determination of oxalate and citrate in human urine 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 fluorophosphate in effervescent tablets using anion chromatography with conductivity detection afterchemical suppression applying a step gradient to elute strongly retained components.

Determination of nitrate in a nickel plating bath using anion chromatography with UV/VIS detection (205 nm) after chemical suppression.

Determination of traces of fluoride and sulfate in 35% hydrochloric acid (HCl) using anion chromatography with conductivity detection after chemical suppression and sample preparation by inline neutralization.

Qualitative determination of chloride, phosphate, and sulfate as well as chlorite, nitrite, chlorate, bromide, and chromate in urine using anion chromatography with conductivity detection after chemical suppression.

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

Determination of glycolate, formate, chloride, nitrite, nitrate, phosphate, sulfate, and oxalate in engine coolant 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, phosphate, and pyrophosphate in human urine and mice urine using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, nitrate, phosphate, and sulfate in a borate effluent using anion chromatography with conductivity detection after chemical suppression.

Determination of chlorate and sulfate in a brine solution (1.5% NaCl) using anion chromatography with conductivity detection after chemical suppression.

Determination of sulfate in gentamicin sulfate using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, phosphate, sulfite, bromide, nitrate, and sulfate in a beer using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, sulfite, sulfate, and thiosulfate in metam potassium (potassium N-methyldithiocarbamate) using anion chromatography with conductivity detection after chemical suppression.

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

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

Determination of oxalate, thiosulfate, and thiocyanate in an amine solution using anion chromatography with conductivity detection after chemical suppression.

Determination of phosphate and sulfate in a liquid polymer sample using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride and sulfate in an electrolyte used in sensors for transcutaneous CO2 measurement using anion chromatography with conductivity detection after chemical suppression.

Determination of acetate and methanesulfonate (MSA) in olsalazine using anion chromatography with conductivity detection after chemical suppression.

Determination of chlorite, bromate, chlorate, glycolate, acetate and formate in the presence of fluoride, chloride, nitrite, bromide, nitrate, phosphate and sulfate using anion chromatography and subsequent conductivity detection following chemical suppression.

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

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

Determination of sulfide, sulfite, sulfate, and thiosulfate in the presence of chloride, nitrate, and phosphate using anion chromatography with combination of suppressed and nonsuppressed conductivity detection.

Determination of chromate in cement using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride and sulfate in ethanol using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, glycolate, acetate, formate, chloride, nitrite, nitrate, and sulfate in the primary cycle water of a pressurized water reactor (PWR) using anion chromatography with conductivity detection after chemical suppression calibrated with Metrohm Inline Calibration.

Determination of chloride, chlorate, and sulfate in soda lye (50% sodium hydroxide) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Neutralization.

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 in green tea using anion chromatography with conductivity detection after chemical suppression.

Determination of sulfate in methanedisulfonic acid using anion chromatography with conductivity detection after sequential suppression.

Determination of hypophosphite, phosphite, and phosphate in a nickel bath using anion chromatography with conductivity detection after chemical suppression and inline cation exchange.

Determination of chloride, sulfite, sulfate, and thiosulfate in a process water using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection.

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

Determination of formate, chloride, nitrate, phosphate, and sulfate in 20% TMAOH using anion chromatography with conductivity detection after sequential suppression and inline matrix neutralization.

Determination of chloride, nitrate, and sulfate in 85% H3PO4 using two-dimensional 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 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.

Determination of the cross contamination of 100 mg/L of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate to ultrapure water using anion chromatography with conductivity detection after chemical suppression and inline ultrafiltration.

Determination of fluoride, hypophosphite, chlorite, bromate, chloride, nitrite, bromide, chlorate, nitrate, phosphite, phosphate, sulfate, arsenate, iodide, chromate, and perchlorate using anion chromatography with conductivity detection after gradient elution and chemical suppression.

Determination of fluoride, hypophosphite, chlorite, bromate, chloride, nitrite, bromide, chlorate, nitrate, phosphite, phosphate, sulfate, and iodide using anion chromatography with conductivity detection after chemical suppression.

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

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

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

Long-term determination of standard anions with automatic inline eluent preparation applying Dosino and Level Control technology using anion chromatography with conductivity detection after sequential suppression.

Determination of chloride, nitrite, nitrate, and sulfate in an ambient aerosol (PM2.5) using aerosol sampling with the PILS (Particle Into Liquid Sampler) and anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate and sulfate in an E85 mixture (85% ethanol and 15% gasoline) by means of anion chromatography with conductivity detection and sequential suppression. The Inline Matrix Elimination serves as sample preparation.

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

Calibration of fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate using intelligent partial loop injection technique and anion chromatography with conductivity detection after sequential suppression. This technique allows a calibration range of 1:100 (e.g. 1 μg/L to 100 μg/L corresponding to 2 μL to 200 μL injected volume) out of 1 calibration solution. Applying the full range of partial loop injection to the samples one calibration covers a sample concentration range of 1 to 10'000.

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

Determination of fosetyl-aluminum in a formulation using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, chloride, nitrate, phosphate, and sulfate on a short column or the ions mentioned plus bromate and nitrite on a long column in water samples applying intelligent column-switching using anion chromatography with conductivity detection after sequential suppression.

Determination of fluoride, chloride, and nitrate in concentrated sulfuric acid (96…98%) using anion chromatography with conductivity detection after sequential suppression.

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, formate, acetate, chloride, nitrite, bromide, nitrate, sulfate, oxalate, and molybdate using anion chromatography with conductivity detection after chemical suppression and Metrohm Inline Dialysis.

Determination of fluoride, chloride, nitrate, phosphate, sulfate, silicate, and hexafluorosilicate (calculated) using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection with post-column reaction (see AN U-48). Hexafluorosilicate is hydrolyzed into fluoride and silicate. Both anion concentrations can be used for the calculation of the SiF62- concentration.

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 perchlorate and thiosulfate using anion chromatography with conductivity detection after sequential suppression.

Determination of acetate, chloride, nitrite, bromide, nitrate, phosphate, sulfate, oxalate, fumarate, and molybdate using anion chromatography with conductivity detection after chemical suppression.

Product consistency and quality is of utmost importance to winemakers. This wine analysis evaluates nutrients and other ionic ingredients, which could potentially have deleterious effects on efficiency and production during the fermentation process. Inorganic and organic anions as acetate, chloride, phosphate, malate, sulfite, tartrate, sulfate, and oxalate are separated and quantified on a Metrosep A Supp 10 - 100/4.0 applying Inline Ultrafiltration and conductivity detection.

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

Determination of octylsulfonate, octylsulfate, dodecylsulfate, and oleate in a shower cream using reversed phase chromatography with conductivity detection after chemical suppression applying gradient elution.

Determination of fluoride, formate, chloride, nitrite, bromide, nitrate, sulfate, oxalate, and molybdate in a coolant using anion chromatography with conductivity detection after chemical suppression and Metrohm Inline Dialysis.

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.

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 AN shows its use for parallel anion and cation determination in tap water applying one single Sample Processor. The cation results are shown in Applicatin Note C-133.

The state-of-the-art tri-chamber suppressor technology provides a fresh suppressor chamber for each measurement. The complete regeneration of the chamber after each sample ensures highly efficient cation exchange – today, tomorrow, and even after years of continuous operation.The chromatograms as well as the statistical data demonstrate the outstanding reproducibility of the measurements with the Metrohm Suppressor Module.

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.

The high-capacity suppressor MSM-HC allows to run analyses with high eluent concentrations, e.g., sodium hydroxide eluents. The determination of anions in washing powder is a typical example where the high pH of NaOH is required for the separation of polyphosphates.

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.

Boiler water analysis is an important task in power plant applications. Under the given conditions, the "Metrosep A Supp 10 - 100/4.0" column separates sulfite and sulfate without any organic modifier in the eluent. Even without any stabilizer, sulfite can be determined with a high reproducibility.

Eluent preparation on demand (EPOD) is the convenient and flexible way of automatic eluent preparation. The 849 Level Control together with an 800 Dosino equipped with a 50 mL dosing unit are used to dilute an eluent concentrate to the final eluent concentration. The use of eluent concentrates is suitable for any type of eluent. This facilitates unattended operation of the system over several weeks (see AN C-134 for cation eluent preparation).

Anion analysis in milk requires a sophisticated sample preparation to avoid column fouling by fats or proteins. Here Metrohm Inline Dialysis is the perfect automated technique. In dairy products iodide, thiocyanate, and perchlorate need to be determined regularly for health and hygiene reasons. This application allows for the first time to analyze these three components in this matrix within one run.

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.

Ionic liquids, also denominated as «designer solvents», are organic salts that are liquid at low temperatures. They are powerful solvents, conduct the electric current, and are therefore used in many applications. Anions, in particular halogenides, are common byproducts in the manufacturing of ionic liquids. Therefore, their concentration has to be controlled.

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

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.

Metrohm Inline Neutralization is a well-established sample preparation technique for anion determinations in hydroxide solutions. The intelligent Partial Loop Injection Technique (MiPT) allows to calibrate the system with one single standard solution and to adjust the injection volume according to the anion concentrations in the sample. This method has been successfully applied to anion analysis in potassium hydroxide (50 and 85%) and in potassium carbonate solutions (83%).

Metrohm Inline Preconcentration Technique with Matrix Elimination (MiPCT-ME) is a powerful tool that combines preconcentration, matrix elimination, and multilevel calibration. The latter only requires a single multi-ion standard solution. The 800 Dosino takes over all liquid handling tasks. The shown system setup allows sample analysis from 0.1 µg/L up to 1.0 mg/L.

The Dose-in Gradient expands the standard IC system to a gradient system. Using isocratic elution for separating the oxyhalides and the anions containing sulfur is very time-consuming. An 800 Dosino and a T-piece are used to expand the isocratic system to a binary gradient system. This is shown in the example of the determination of the standard anions, in addition to chlorate, thiosulfate, thiocyanate, and perchlorate.

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.

Cola drinks (also known as soft drinks) contain a high amount of phosphoric acid. Quality control of these beverages includes determining the phosphate content. Phosphate analysis also indicates the dilution factor of the phosphate concentrate during cola processing. Achieving proper dilution of the concentrates is in the best interest of soft drink producers and bottling companies to ensure the highest quality beverages are made for consumers.

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.

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

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.

The separation of short-chain organic acids from fluoride and chloride requires diluted eluents. These weak eluents, however, induce long retention times for divalent anions. Adding a stronger eluent later in the separation sequence by use of a Dose-in Gradient makes these anions elute more rapidly. Furthermore, the Dose-in Gradient offers the advantage of low equipment and technical expense.

The determination of low nitrite concentrations in the presence of excess sodium chloride is demanding due to the small retention time difference of these two anions. Dual detection – conductivity and UV/VIS – is a powerful method for determining nitrite traces in a 20 g/L sodium matrix. The UV/VIS chromatogram displays no chloride interferences. The determination of ammonium traces in the presence of excess sodium is described in AN-C-145.

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.

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.

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.

Cleanliness is indispensable in electronics production. Ionic contaminations in particular lead to a drastic worsening of the quality of the printed circuit boards. The present Application Note describes the determination of anions on printed circuit board surfaces. The intelligent Partial Loop Injection Technique (MiPT) used for this purpose permits the determination of cations and anions in the same sample. The determination of the cations is described in AN-C-149.

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.

Fast IC means a high sample throughput. This is attained with short columns, relatively high flows and strong eluents. Malate, tartrate, oxalate as well as sulfate are separated within three minutes.

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

Fast IC means a high sample throughput. This is attained with short columns, relatively high flows and strong eluents. Sulfite can be determined in beer alongside sulfate and other anions with the Metrosep A Supp 10 - 50/4.0.

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

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

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.

Strong citrate retention delays chromatographic anion determination in beverages containing citric acid. The use of a step gradient reduces the retention time of the citrate, thus considerably shortening the analysis period.

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

FDG gypsum originates from flue gas desulfurization systems in power plants. VGB-M 701 E (2008) describes aqueous extraction methods for determining chloride in FDG gypsum using ion chromatography. The sample preparation described in the VGB permits the determination of other anions besides chloride.

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.

The Metrosep A Supp 5 microbore anion column is available in 150 and 250 mm lengths. For the two columns, the run times for separating the 7 standard anions are 20 and 29 minutes. In addition to the good separation properties and the short running times, microbore columns use approximately 75% less eluent than does their 4 mm counterpart.

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.

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

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.

The stability of the Metrosep A Supp 5 - 250/4.0 column 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 10 weeks and counted a total of 2,150 injections. The results show an outstanding reproducibility and verify the high column stability.

Aromatic dicarboxylic acids, e.g., terephthalate, isophthalate and 5-sulfoisophthalate, are important monomers in the manufacture of polyesters and alkyd resins. The monomer ratio of the dicarboxylic acids has an enormous influence on polymerization. The separation of the late-eluting components is completed within 15 minutes if a short Metrosep A Supp 15 - 50/4.0 type column is used together with high eluent concentrations and flow rates.

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.

High-pressure gradients combine the advantages of weak and concentrated eluents. Weak eluents promote the separation of the components that elute early and in close proximity to one another; in contrast to this, concentrated eluents accelerate the analysis of the components that are stronger retained at the column. The high-pressure gradient used in this application makes it possible to separate 15 organic acid anions in a single run. The blank subtraction option in the MagIC Net software simplifies the allocation of the peaks and with it the quantification.

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.

4-Hydroxybutyrate (GHB) is numbered among the hydroxycarboxylic acids and is used as a psychoactive drug which is illegal in many countries. GHB can be determined through anion chromatography with suppression. GHB can be separated from the standard anions and the organic acid anions glycolate, acetate and formate on the Metrosep A Supp 16 - 250/4.0 column and under the conditions specific in this Application Note.Key words: Liquid Ecstasy, KO drops

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.

Hydrogen sulfide (H2S) and carbon dioxide (CO2) are disruptive byproducts of natural gas that must be eliminated during conveyance. This is accomplished with the aid of gas scrubbing, during which the gas flow is cleaned with absorbers such as alkanolamines or akylalkanolamines (e.g., methyldiethanolamine, MDEA). Reliable analysis is imperative, given that heat-stable salts often accumulate in the absorber and thus inhibit the absorption capacity for acid gases.The determination of heat-stable salts (SCN–, S2O32–, SO32–, SO42–, etc.) in MDEA solutions takes place on the Metrosep A Supp 5 - 250/4.0 column with conductivity detection following sequential suppression.Key words: amine gas treating, scrubber

Electronic-grade nitric acid may not contain more than the slightest traces of anion contaminations (in the mg/L range). The ion chromatography determination of these kinds of anion traces requires not only a high-capacity column but also an eluent that allows the nitrate to be eluted by the column, although only after all of the other ions of interest have been eluted. This separation is achieved on a column of the Metrosep A Supp 16 - 250/4.0 type with the aid of a strong carbonate/hydrogen carbonate eluent.

β-glycerophosphate and malate are determined in a pharmaceutical formulation. Excellent separation of β-glycerophosphate and malate from α-glycerophosphate and phosphate is possible with the aid of a carbonate eluent and the Metrosep A Supp 7 - 250/4.0 column.

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.

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

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.

In ion chromatography with suppressed conductivity detection, calibration curves quite often are not really linear. Especially, if a calibration has to cover a large concentration range, results will be more accurate when multiple calibration curves for different concentration ranges are applied. The MagIC Net software allows to apply multiple calibration curves within one single determination. This means that for every ion the optimal calibration is applied, improving the accuracy of the results. This method is applied to rainwater samples.

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.

Glycolate and lactate have to be determined in a dual phase varnish remover. Analyzed is only the upper aqueous phase. The separation is achieved on a Metrosep A Supp 16 - 250/4.0 column. The eluent composition is adapted to get a sufficient separation of glycolate and lactate without interference by formate and acetate. Conductivity detection after sequential suppression is applied.

Pyrophosphate is used as a stabilizer in aqueous hydrogen peroxide solution. “Reagent grade” solutions may contain pyrophosphate in the higher mg/L range, while “electronic grade” hydrogen peroxide should be free of this stabilizer. Here the determination of pyrophosphate in a high purity H2O2 solution (30%) is performed applying Inline Preconcentration with Matrix Elimination (MiPCT-ME) and a Dose-in Gradient.

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

The Eco IC is an entry-level instrument that is particularly suitable for routine operations and water analysis. It is equipped with a conductivity detector and can be used both with and without chemical suppression. This Application Note describes the determination of anion content with the Metrosep A Supp 17 - 250/4.0 column. This column model is particularly suitable for water analysis at room temperature.

Monofluorophosphate is used in toothpaste to prevent dental caries. USFDA allows up to 1.5 g/kg fluoride corresponding to 11.5 g/kg sodium monofluorophosphate on over the counter (OTC) dentifices for adults and children above 6 years. Here, a toothpaste is analyzed for monofluorophosphate by ion chromatography applying conductivity detection after chemical suppression.

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.

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

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.

N,N-dimethylglycine is an amino acid derivative found in plants and animals. The respective sodium salt is available as nutritional supplement. In this context it is expected to have athletic performance enhancer effects and acts against fatigue. It is also accepted as a poultry feed addition. The determination is performed applying a Dose-in Gradient with subsequent conductivity detection after sequential suppression. To enhance the selectivity of the separation, a combination of a Metrosep A Supp 7 - 250/4.0 and a Metrosep A Supp 16 Guard/4.0 was used.

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.

Eltrombopag is a pharmaceutical agent used in certain conditions of thrombocytopenia. As such it is an orphan drug. The molecule of Eltrombopag is a protonated aromatic carboxyl compound. Under ion chromatography condition (alkaline eluent), it can be deprotonated and can thus block ion exchanger sites on the column. This results in decreasing retention times over time. To avoid this, Inline Matrix Elimination is applied, where the protonated Eltrombopag is washed off the preconcentration column before injection. Nitrite is then analyzed with conductivity detection after sequential suppression.

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.

Metrohm Inline Sample Preparation (MISP) is a collection of versatile, time- and cost- effective techniques reducing manual sample preparation. This Application Note describes the combination of Inline Dilution with Inline Ultrafiltration. Samples are automatically diluted and subsequently filtered before injection. MagIC Net allows to run intelligent dilution by checking results and rediluting the sample if the result is out of the calibration range. Also the multipoint calibration is performed by automatically diluting the stock standard solution. In this way, an automatic calibration of each analyte is effectively achieved.

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.

Ultrapure chemicals are required in the semiconductor industry. Ionic impurities may lead to compromised products. This application describes the determination of anionic impurities in semiconductor grade 28% ammonium hydroxide solution. To avoid matrix disturbances, Inline Neutralization and Inline Preconcentration with Matrix Elimination needs to be applied.

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.

Perchlorate is known as a potential contaminant in drinking water. Besides very few natural sources, it mainly originates from disinfectants, bleaching, propellants, etc. EPA method 314.0 requires to reach a method detection limit of 0.5 µg/L for perchlorate in reagent water. But also water with a very high content of total dissolved solids needs to be analysed by this method. Making use of the Metrosep A Supp 7 - 250/4.0 column fulfills all requirements of this method.

The STREAM (suppressor treatment reusing eluent after measurement) is applied since quite some time. The suppressor rinsing with suppressed eluent is advantageous over ultrapure water rinsing: a smaller water dip, faster MSM equilibration, and the avoidance of an additional water supply are just a few. Injecting samples containing iron in the matrix under sulfuric acid regeneration yields reduced peak areas and broader peaks for phosphate. Switching to a regenerant based on sulfuric and oxalic acid allows full regeneration of the MSM. The overlay above shows three subsequently taken chromatograms after more than 300 injections of 10 mg/L iron(II) onto one single MSM chamber. No difference in peak shape or peak area is observed.

Pamidronate is applied to treat osteoporosis by strengthening the bones. It is a bisphosphonate containing a primary amine group. Phosphite and phosphate are related compounds, which need to be quantified. USP requires the use of formic acid eluent with refractive index detection. But a standard IC procedure offers an alternative with better sensitivity. Phosphite and phosphate are analyzed with conductivity detection after sequential suppression.

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 disinfection byproducts in water is a standard application for ion chromatography. Applying conductivity detection the separation of chlorite and bromate from chloride is crutial for μg/L detection limits. The combination of a Metrosep A Supp 7 - 250/4.0 and a Metrosep A Supp 16 Guard/4.0 lead to an improved separation. The Limit of Quantification for bromate is around 1 μg/L

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

Potassium chloride and potassium bicarbonate effervescent tablets are used to prevent potassium deficiency. Pharmaceutical manufacturers and labs adhere to strict quality regulations using USP-NF monographs. Ion chromatography with suppressed conductivity detection, utilizing the Metrosep A Supp 16 - 100/4.0 (L91) column, is approved by the USP to quantify chloride content in these tablets, following validation per USP General Chapter <621>.

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.

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.

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.

«High ionic water» is typically water containing a high concentration of chloride (e.g. seawater, brine), but this also describes water samples resulting from petrochemical processes. Due to the high chloride concentrations, the conductivity determination of minor ionic components is limited. Thus, minor anions like nitrite, bromide, and nitrate can elute under or on the tail of the large chloride peak, and their detection in low concentrations is hampered. However, combining conductivity and UV/VIS detection as described in ASTM D8234 enables the determination of anions that are UV active. Chloride does not interfere in this situation. The described technique enables the interference-free simultaneous determination of trace anions besides high chloride content.

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.

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.

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.

Food waste is an important raw material for biogas production. However, during the fermentation process, phenylacetate can be produced from phenylalanine. As phenylacetate inhibits bacterial growth and their metabolism, it is an important parameter to monitor in order to guarantee a successful fermentation process. Aside from phenylacetate, chloride, nitrate, sulfite, sulfate, phosphate, and thiosulfate are also determined in the fermentation broth sample.

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.

OpenLab CDS is the newest generation of chromatography data systems from Agilent. The Metrohm IC Driver 1.0 for OpenLab CDS implements Metrohm ion chromatographs in OpenLab CDS for full control and data acquisition. This application shows the use of a gradient (Dose-in Gradient) as well as Dosino Regeneration in OpenLab CDS. Fluoride, chloride, nitrite, bromide, nitrate, sulfate, phosphate, and iodide in a standard solution are separated and determined.

OpenLab CDS is the newest generation of the Agilent chromatography data systems platform. The Metrohm IC Driver 1.0 for OpenLab CDS enables introducing Metrohm IC instruments to this platform for full control and data acquisition. This application shows the analysis of iodide by amperometric detection, enabling detection at trace levels. The eluent is produced automatically by the 941 Eluent Production Module. In this way, amperometric detection can be executed with the same functionality and performance as with MagIC Net.

Stannous fluoride gel for pharmaceutical use needs to comply with USP requirements. The actual monograph (USP 42) utilizes two different methods for the identification and the assay. Ion chromatography allows the analysis 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.

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.

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

In 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>.

In the petrochemical industry, natural gas is processed to remove contaminants and meet product specifications. Process contaminants include acidic gases such as hydrogen sulfide and carbon dioxide, which can corrode costly refinery equipment downstream. Typically, the acidic gases are removed via alkanolamine treatment using monoethanolamine (MEA) or methyldiethanolamine (MDEA). The amine solutions absorb the acidic gases, and then the amine compounds are removed from the natural gas. In addition to the acidic gases, heat stable salts (HSS) that remain in the natural gas are also corrosive to the treatment plants. These are also removed via gas sweetening and need to be determined in the used gas sweetening amine solution. Some typical heat stable salts of interest include acetate (1), formate (2), chloride (3), phosphate (4), sulfate (5), oxalate (6), thiosulfate (7), and thiocyanate (8).

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.