Aplikácie

Available sample size, mass sensitivity, efficiency and the detector type are important criteria in the selection of separation column dimensions. Compared to conventional 4 mm i.d. columns, microbore columns excel, above all, by their low eluent consumption. Once an eluent is prepared, it can be used for a long time. Additionally, the lower flow rates of microbore columns facilitate the hyphenation to mass spectrometers due to the improved ionization efficiency in the ion source.With the same injected sample amount, a halved column diameter involves a lower eluent flow and results in an approximate four-fold sensitivity increase. In a converse conclusion, this means that with less sample amount, microbore columns achieve the same chromatographic sensitivity and resolution than normal bore columns. This makes them ideally suited for samples of limited availability.

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

Metrohm's iColumns are the first IC columns that are equipped with a data chip that stores freely definable data, fixed column data as well as data entered by the MagIC NetTM software. Any relevant information such as column type, standard parameters, maximum pressure, etc. can be called up at any time. Analysis data continuously entered by the MagIC NetTM software guarantees a complete column and GLP-compliant surveillance irrespective of the IC system in which the column is operated. The MagIC NetTM software surveys the critical column data and indicates any infringement of limits.

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.

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.

Cation analysis in drinking water is a routine task in ion chromatography and can be achieved with a variety of separating columns. The use of a microbore Metrosep C 6 - 250/2.0 column with a high eluent concentration makes it possible to reduce analysis time to less than 12 minutes. Very symmetrical peaks with high sensitivity for the divalent cations are also achieved. Direct conductivity detection is applied.

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

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.

This work was carried out with a Metrosep C 2 - 150 separation column, the following eluent parameters being investigated: nitric, tartaric, citric and oxalic acid concentration and concentration of the complexing anion of dipicolinic acid (DPA). The aim was to determine the effect of these parameters plus that of the column temperature on the retention times of alkali metals, alkaline earth metals, ammonium and amines using ion exchange chromatography with non-suppressed conductivity detection. Due to similar affinities for the ion exchange column, transition metals are difficult to separate with the classical nitric, tartaric, citric and oxalic acid eluents. Partial complexation with the dipicolinate ligand significantly shortens the retention times and improves the separation efficiency. However, too strong complexation results in a rapid passage through the column and thus in a complete loss of separation. Apart from a change in the elution order of magnesium and calcium at high DPA concentrations, other non-amine cations are only slightly affected by the eluent composition. Irrespective of the tartaric acid and nitric acid concentration in the eluent, an increase in column temperature shortens the retention times and slightly improves the peak symmetries of organic amine cations, particularly in the case of the trimethylamine cation. In contrast, an increase in column temperature in the presence of DPA concentrations exceeding 0.02 mmol/L increases the retention time of the transition metals. Depending on the separation problem, variation of the pH value, the use of a complexing agent and/or an increase in column temperature are powerful tools for broadening the scope of cation chromatography.

Comparative measurements show that the new Metrosep C 4 cation column has even better separation characteristics than the previous Metrosep C 2 and Metrosep Cation 1-2 column types. The Metrosep C 4 column has a clearly improved peak shape which leads to a better separation of the individual peaks. Using Metrosep C 4 the number of theoretical plates per meter was noticeably higher than that obtained on the Metrosep C 2 or C 1-2 column. Additionally for standard cations transition metals and amines, the Metrosep C 4 column shows better results with respect to peak shape, peak height, resolution and asymmetry factor. The clearly improved resolution of the C 4 column with its narrow and high peaks achieves baseline separation for six standard and six transition metal cations. Analysis times and peak areas obtained with the C 4 column are in the same range as those obtained with its predecessors.As a result of the latest production methods and materials, the promising Metrosep C 4 column excels by an outstanding separation performance for complex mixtures comprising standard cations, transition metal cations and amines.

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

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.

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.

Determination of carbohydrates on the column Hamilton RCX-30 - 250/4.6 using pulsed amperometric detection.

Determination of carbohydrates on the column Hamilton RCX-30 - 150/4.6 using pulsed amperometric detection.

This Bulletin describes the determination by ion chromatography of anions, particularly fluoride, chloride, nitrite, bromide, nitrate, and sulfate using the Hamilton PRPX100 IC anion column without chemical suppression.

The column temperature influences the duration of the cation separation on the high-performance Metrosep C 6 - 150/4.0 column. The retention times of lithium, sodium, ammonium, magnesium, and calcium remain practically constant with increasing column temperature, whereas those of potassium, strontium, and barium are considerably shortened. This means that the temperature can be used to reduce analysis time considerably on the Metrosep C 6 - 150/4.0.

UV/VIS detection is one of the most sensitive detection techniques in trace-level chromatography. Sometimes, however, spectrophotometric detection lacks sensitivity, selectivity or reproducibility and chemical derivatizations are required. By using Metrohm`s rugged and versatile flow-through reactor, single- or multi-step derivatizations can be done fully automatically, in either pre- or post-column mode at any temperature between 25…120 °C. The variable reactor geometry allows to adjust the reactor residence time of the reactants according to derivatization kinetics. The flexibility of the reactor is demonstrated by optimizing four widespread post-column techniques: the relatively slow ninhydrin reaction with amino acids and the fast derivatizations of silicate, bromate and chromate(VI).

Determination of aluminum using cation chromatography, post-column reaction and UV detection.

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).

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

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.

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 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.

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.

The column stability of the Metrosep C 6 - 250/4.0 was determined in long-term laboratory tests. Two injection series per day were run on each of 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 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.

Determination of traces of lutetium, ytterbium, thulium, erbium, terbium, gadolinium, samarium, neodymium, praseodymium, cerium, and lanthanum using cation chromatography with gradient elution and UV/VIS detection after post-column reaction with Arsenazo III.

The high-capacity Metrosep C 6 - 150/4.0 cation column convinces with outstanding separations, narrow peaks, and a multitude of available eluents. In this Note, the selectivity for alkali, earth alkali, and certain transition metals, in addition to methyl and ethanol amines, is shown using a nitric acid eluent and direct conductivity detection.

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.

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.

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

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

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

Mono- and disaccharides, often just called sugars, are constituents in many food products. They need to be quantified for declaration reasons. A flow gradient – on a microbore Metrosep Carb 2 - 250/4.0 column – ensures the separation of the monosaccharides while the disaccharides still elute before 50 min.

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.

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.

Sucralose is an artificial, non-nutritive sweetener that is approximately 600 times sweeter than saccharose. Sucralose is used in low-calorie refreshments such as soft drinks. Sucralose lends itself readily to determination there using ion-exclusion chromatography. A post-column addition of NaOH is required prior to pulsed amperometric detection.Keywords: E 965

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.

Maltodextrin is a polysaccharide consisting of glucose units. Maltodextrins are classified as dextrose equivalents (DE, with DE = 3–20). This application shows the determination of glucose (DE = 1), maltose (DE = 2) till maltoheptaose (DE = 7). The separation is achieved on a Metrosep Carb 2 - 250/4.0 column with subsequent pulsed amperometric detection (PAD).

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

Determination of copper, zinc, iron(II), and manganese in red wine using cation chromatography with UV/VIS detection after post-column reaction with PAR.

Intelligent Inline Preconcentration with Inline Matrix Elimination (MiPCT-ME) is used for trace determination of the six standard cations in addition to zinc and diethylamine. The analysis is completed within 24 minutes on the Metrosep C 4 - 250/2.0 Microbore column. The recovery rates are in excess of 95%. The detection limits calculated with the MagIC Net software are in the lower ng/L range for a preconcentration volume of 4 mL.

Speciation analysis is an important tool in analytical chemistry giving information about the quantitative distribution of different oxidation states of one and the same metal ion. The speciation of iron(II) and iron(III) (Fe 2+/Fe 3+) is achieved by ion chromatographic separation of their anionic dipicolinic acid complexes. Afterwards, post-column reaction with 4-(2-)pyridylazo-resorcinol (PAR) allows VIS detection at 510 nm.

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.

Determination of chloride in concentrated nitric acid using anion chromatography with conductivity detection and chemical suppression.

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

Determination of lithium, sodium, ammonium, potassium, manganese, calcium, magnesium, strontium, and barium using cation chromatography with direct conductivity detection.

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

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. 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. 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 on columns with a relatively high flow rate and the standard eluent. Mono-, di- and trimethylamine are separated with the Metrosep C 4 - 150/2.0 within four minutes.

Fast IC means short run times and a high sample throughput on columns with a relatively high flow rate and the standard eluent. Mono-, di- and tri-ethanolamine are separated with the Metrosep C 4 - 150/2.0 within 2.5 minutes.

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.

Fast IC means short run times on separation columns with a relatively high flow rate and the standard eluent. Here the standard cations are separated within eleven minutes on the Metrosep C 4 - 250/2.0. The sodium and ammonium peaks are separated from one another under these conditions.

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

Determination of fluoride, chloride, nitrate, phosphate, and sulfate in wastewater 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.

The analytical challenge treated by the present work consists in detecting sub-ppb concentrations of low-molecular-weight amines in the presence of strongly retained cationic drugs by using ion chromatography (IC) with upstream inline coupled-column matrix elimination (CCME). In contrast to direct-injection IC, where the late elution of strongly retained drugs requires eluents with added acetonitrile, the CCME technique uses two preconcentration columns in series. In an «inverse matrix elimination step, cationic drug and target amines are trapped on a high-capacity and a very-high-capacity preconcentration column, respectively. During amine determination, a rinsing solution flushes the drug to waste. This significantly shortens the analysis time and improves sensitivity as well as selectivity. Besides the determination of monomethylamine in Nebivolol hydrochloride discussed here, the CCME technique is a promising tool for detecting further low-molecular-weight amines in a wide range of drugs.

Fast IC means short run times on separation columns with a relatively high flow rate. Separation with the Metrosep C 4 - 150/2.0 is even quicker than that in the AN-C-150 at 1.1 mL/min. Here, the standard cations are separated within five minutes. Under the selected conditions, sodium and ammonium are no longer completely separated.

Determination of hydroxylamine, ethanolamine, triethanolamine, and hydrazine using cation chromatography with direct conductivity detection.

Determination of cyanide using anion chromatography with amperometric detection at the silver electrode.

Determination of organic acids and phosphate using ion-exclusion chromatography with direct conductivity detection.

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

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.

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

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 methylamine in the presence of sodium, ammonium, potassium, magnesium, and calcium using cation chromatography with direct conductivity detection.

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.

Determination of chloride and sulfate in the presence of high nitrate concentrations. Optimization of the chromatographic separation by variation of the temperature and eluent composition.

Determination of traces of ammonium in the presence of sodium, potassium, magnesium, and calcium using cation chromatography with direct conductivity detection.

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

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.

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

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>.

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.

Maritime pore water contains sodium in the percentage range. The analysis of ammonia in this kind of sample requires a high column capacity and an exceptionally good separation of sodium and ammonia. These requirements are completely fulfilled by a 2 µL injection to the high-capacity Metrosep C 6 - 250/4.0 column.

A low-pressure gradient enables the separation of sugar acids strongly retained on the column and sugars within an appropriate analysis time. The saccharides are separated on a column of the Metrosep Carb 2 - 250/4.0 type with subsequent pulsed amperometric detection (PAD). Galactose and arabinose are not completely separated under the selected conditions.

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>.

As a rule, brine samples are diluted extremely in order to avoid overloading the column. Manual dilution is very error-prone, which is why this application relies on injection with a 0.25 µL internal loop, thus saving an additional dilution step. Sodium, potassium, magnesium and calcium in brine are determined on a Metrosep C 6 - 150/4.0 column with subsequent direct conductivity detection.

This Application Note describes the determination of N,N-diethylhydroxylamine (DEHA), triisopropanolamine (TIPA) and a cationic color developing component (CDC) in a developer solution. The analysis is performed on a high-capacity column such as Metrosep C - 250/4.0 with subsequent direct conductivity detection. To reduce the residence time of the strongly retained color developer components, the column flow rate is increased after the elution of the amines.

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.

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.

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.

The determination of cyanide and sulfide in the trace range requires an alkali eluent and amperometric detection. This Application Note describes a new column/eluent combination for optimized separation. The combination consists of the Metrosep A Supp 10 - 100/2.0 Microbore Column and a sodium hydroxide eluent that contains traces of EDTA for the complexation of the transition metals. This yields a better peak shape and detection limits below 0.05 µg/L.

Stevia is a plant of the Compositae family, the leaves of which can be used as a sweetener. In order for it to be used in the food sector, the purity of the steviol glycosides contained in the Stevia must be monitored. Utilization of the flexIPAD potential profile yields a greater sensitivity than standard PAD. The separation is accomplished on an RP column. Post-column addition of sodium hydroxide enables amperometric detection.

The analytical challenge treated in the present work consists in detecting trace concentrations (ppb) of bromide in the presence of a strong chloride matrix. This problem was overcome by separating the bromide ions from the main fraction of the early eluting chloride matrix (several g/L) by applying two sequential chromatographic separations on the same column. After the first separation, the main fraction of the interfering chloride matrix is flushed to waste, while the later eluting anions are diverted to an anion-retaining preconcentration column. After elution in counter flow, the bromide ions are efficiently separated from the marginal chloride residues. The four-point calibration curves for bromide and sulfate are linear in the range of 10…100 µg/L and 200…800 µg/L and yield correlation coefficients of 0.99988 and 0.99953 respectively. For the method shown here, a second injection valve and a preconcentration column are the only additional devices needed to master this demanding separation problem.

Cation content in snow is greatly dependent on sampling site. Roadside samples are likely to exhibit a high sodium content caused by the use of road salt. This application shows the analysis of a snow sample from a roadside. Separation is performed on a microbore Metrosep C 6 - 250/2.0 column with direct conductivity detection. The 250 mm column was selected due to the large difference in concentrations between sodium and ammonia. This condition enables a baseline separation of the two cations.

Pure sodium chloride contains much less iodide than e.g., table salt which usually is fortified with it. Trace determination of iodide is easily performed applying ion chromatography with amperometric detection. This detection mode is particularly selective and sensitive. The actual separation is achieved using a Metrosep A Supp 5 - 250/4.0 column. The detection happens at a silver working electrode. LOQ is at approximately 1.0 μg/L (in solution) and 50 μg/kg in the sample. The use of a shorter column might further improve the LOQ.

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.

Isopropylamine and dicyclohexylamine are used as emulsifiers and need to be determined in emulsions along with standard cations. However, emulsions must not be injected directly into the ion chromatograph as the organic components may damage the ion exchanger stationary phase in the separation column. Inline Dialysis as sample preparation is the perfect tool for such samples. The ions of interest are separated from the organic phase by diffusion through the hydrophilic membrane, thus protecting the column. Full automation makes the analyses even easier and more efficient for the user.

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.

Whey is the remaining liquid after cheese production. It is mainly used as feed. It is also used as dietary supplement as a beverage or in powder form. This application determines lactic acid as well as cations in one determination. The Metrosep C 6 - 250/4.0 column separates sodium, potassium, magnesium, and calcium by ion exchange. It also acts as an ion-exclusion column, which separates lactic acid. Both lactic acid and the cations can be determined in the same run applying direct conductivity detection. While cations typically elute as negative peaks, lactic acid elutes as an early positive peak. MagIC Net shows both in the usual positive direction.

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.

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

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

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.

Determination of NTA, EDTA, and DTPA in surface water and wastewater using ion pair chromatography with UV-detection after post-column reaction with the MSM.

Determination of sucrose, glucose, and sucralose in a low-calorie sweetener using ion-exclusion chromatography with pulsed amperometric detection after post-column addition of sodium hydroxide.

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.

This poster discusses results showing the influence of pH, temperature of the post-column reactor, eluent composition, and iodide concentration on the sensitivity of the triiodide method.

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.

This Application Note describes the separation of inositol, mannitol, glucose, xylose, fructose, lactose, sucrose and cellobiose on a column of the Metrosep Carb 2 - 150/4.0 type with subsequent pulsed amperometric detection (PAD).

Sulfide and cyanide are toxic anions. Their trace determination in any kind of water samples, especially in wastewater, is requied for safety reasons. However, metal traces present in the eluent can mask target anions due to complexation. The addition of a stronger complexing agent to the eluent mask these metal cations enabling interference free determaination. This application is mainly used for the analysis of cyanide and/or sulfide in water. However, it also fulfills the requirements of ASTM D2036 for the determination of total, amenable, weak acid dissociable cyanides. The determination of cyanide and sulfide require an alkaline eluent and amperometric detection. This Application Note describes a new column/eluent combination for optimized separation. The combination consists of the Metrosep A Supp 10 - 100/4.0 column and a sodium hydroxide eluent containing a trace of EDTA for transition metal complexation. This yields in better peak shape and detection limits below 0.1 μg/L.

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>.

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

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.

The separation of sugar and sugar alcohols in beverages is performed on a Metrosep Carb 2 - 150/4.0 type column using sensitive pulsed amperometric detection as the detection method. The method is explained exemplarily on an apple beverage.

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.

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.

The analytical challenge treated in the present work consists in the determination of chloride, phosphate and sulfate in the presence of difficult sample matrices that interact with the stationary column phase or even render it unusable. Metrohm`s patented stopped-flow dialysis coupled to the new 881 Compact IC pro ion chromatograph overcomes these drawbacks. Two standard solutions covering the concentration ranges 1.0…3.6 mg/L and 10…36 mg/L as well as two samples, an ultra-high temperature (UHT) processed milk and a baby milk powder, were characterized in terms of analyte concentration, relative standard deviation, calibration quality, carryover and recovery rates. While the five-point calibration curves yielded correlation coefficients (R) better than 0.9999, carryover (between two subsequent injections of a concentrated sample and a blank) was less than 0.49%. Recoveries for the low (10…36 mg/L) and high standard concentrations (1.0…3.6 mg/L) were within 91…99% and 94…100%, respectively. Automated compact stopped-flow dialysis is a leading-edge sample preparation technique that ensures optimum separation performance by effectively protecting the column from detrimental matrix compounds.

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.

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>.

Scrubber solutions for scrubbing flue gas often contain amines for absorbing acid gases, e.g., sulfur dioxide (SO2). 1-(2-hydroxyethyl)piperazine and 1,4- Bis(2-hydroxyethyl)piperazine from gas scrubber solutions are separated in the Metrosep Carb 2 - 150/4.0 column and then determined using pulsed amperometric detection.

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.

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.

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.

By means of azide analysis in Irbesartan a simple, fast, precise and accurate ion chromatographic method for the determination of traces of inorganic contaminants in pharmaceuticals is described. Traces of toxic azides in pharmaceutical products can accurately be determined in the sub-ppb range after Metrohm Inline Matrix Elimination using isocratic ion chromatography (IC) with suppressed conductivity detection. While the azide anions are retained on the preconcentration column, the interfering pharmaceutical matrix is washed away by a transfer solution, ideally consisting of 70% methanol and 30% ultrapure water. The analytical setup provides a well-resolved azide peak and thus alleviates the common drawback of excipient interferences, especially from the nitrate anion. Calibration with azide standards is linear over the range of 5…80 ppb, providing a coefficient of determination of 0.9995. The limit of detection (LOD) and the limit of quantification (LOQ) of azide in Irbesartan are 5 and 30 µg/L respectively; the relative standard deviations (RSD) for the peak area, peak height and retention time being smaller than 3.9%. Robustness testing involved variation of column oven temperature and composition of the transfer solution and, in terms of peak area, provided RSDs smaller than 2.8% and 3.1% respectively.

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

Besides the typical sugar components, orange juice contains inositol. This sugar alcohol serves as an important signaling and messenger molecule. This Application Note shows the determination of inositol besides glucose, fructose, and sucrose in orange juice on a Metrosep Carb 2 - 150/4.0 column with pulsed amperometric detection (PAD).

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 sample preparation for ion chromatography is divided into steps which should generally be implemented to preserve the column and into steps which should be performed to obtain an improved chromatogram. The goal is to have the test substance in ionic form in solution without the presence of interfering substances.

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

Before the liquefaction process of the natural gas, carbonate and hydrogen sulfide need to be removed through a scrubber solution containing piperazine and N-methyl diethanolamine (MDEA). The concentration ratio of the two components is determined by ion chromatography on a Metrosep C 4 - 150/4.0 column applying direct conductivity detection.

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.

Alendronate, also referred to as alendronic acid, is a biphosphonate used to treat osteoporosis. It is the main ingredient in the tablets and is determined in accordance with the Chinese Pharmacopoeia (2015). Separation takes place in the Metrosep A Supp 4 - 250/4.0 column; direct conductivity detection is used for quantification.

Reducing the analysis time is a demanding task because it is accompanied by a parallel reduction of peak resolution. With a Microbore column 100 mm in length, standard cations in tap water can be determined in only 5 minutes. Strontium can also be determined by simply extending the run time to 6.5 min.

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

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.

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.

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.

Metrohm Inline Preconcentration Technique with matrix elimination (MiPCT-ME) is a powerful method that combines preconcentration, matrix elimination, and multilevel calibration. In this Application Note, the methodology is applied to the determination of traces of sodium in addition to 2 mg/L ammonia. The Metrosep C 6 - 250/4.0 column is used for selectivity reasons.

EU Regulation 1169/2011 defines rules for nutrition declaration on foodstuffs. The objective is to provide food information to the general public and to label food ingredients that are hazardous to health when consumed in larger quantities. This Application Note describes the determination of fruit yogurt with the aid of the Metrosep Carb 2 - 150/2.0 column.

Gentamicin is an aminoglycoside antibiotic and is composed of a number of related gentamicins. It is applied for several types of infections. For the determination of the major components, USP asks for chromatographic separation with pulsed amperometric detection using a gold working electrode. A post-column addition of NaOH is performed prior to the detection.

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.

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.

Polyols and sugars in soaps enhance the stability and the size of air bubbles and foam. In addition to the polyol glycerin, sugar alcohols and sugars are often added to soaps. The determination of sorbitol and saccharose in a transparent soap takes place on a column of the Metrosep Carb 2 - 150/4.0 type with subsequent pulsed amperometric detection (PAD).

EU Regulation 1169/2011 defines rules for nutrition declaration on foodstuffs. The objective is to provide food information to the general public and to label food ingredients that are hazardous to health when consumed in larger quantities. This Application Note describes the determination of three sugars in apple juice with the aid of the Metrosep Carb 2 - 150/2.0 column.

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.

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.

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.

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.

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.

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 separation of lactose, lactobionic acid, sialic acid*, 6’-sialyllactose, and 3’-sialyllactose is shown as a proof of concept for the control of these components in fermentation process for a pharmaceutical product. The acceptance criterion of a minimum resolution of the peaks (< 1.3) is reached. The separation is achieved on a Metrosep Carb 2 - 250/4.0 column with subsequent pulsed amperometric detection.

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.

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.

2-amino-N-(2,2,2-trifluoroethyl)-acetamide is a organic building block for synthesis of pharmaceutical products. Its purity is crucial for the success of the respective synthesis step. 2,2,2-trifluoroethylamine, glycine, and inorganic cations are of interest. Their total peak area is required to be < 2 % of the peak area of all peaks above the reporting level. Separation and quantification is achieved on a Metrosep C 4 - 250/4.0 cation column.

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

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

Lactose intolerance means that lactose cannot be digested. Lactose is contained in milk and milk products. "Lactose-free milk" is analyzed following Inline Dialysis. No lactose was detected in the milk sample investigated. The chromatogram of the spiked sample corresponds to the limit value of 100 mg/L that applies for lactose-free milk. The separation is performed on the Metrosep Carb 2 - 150/4.0 column.

Propylene glycol, also called propane-1,2-diol, is a humectant and applied in topical solutions to increase the solubility of the active pharmaceutical ingredient (API) or the ability to penetrate the skin. In this application, propylene glycol is determined in a placebo and two topical solutions containing diclofenac as the API. The separation is achieved on a Hamilton RCX-30-250/4.0 column with subsequent pulsed amperometric detection (PAD).

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.

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.

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.

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 and trimethylamine N-oxide (TMAO) are indicators for the quality of grape fermentation. The consumption of amine-rich wines often leads to headaches, which is why the amine concentrations in wine must be monitored. This Application Note describes the determination of trimethylamine N-oxide, putrescine, cadaverine and histamine, in addition to various standard cations, with the aid of the Metrosep C 6 - 100/4.0 column and subsequent direct conductivity detection.

In natural gas production, the removal of contaminants, and in particular acidic gases such as H2S and CO2, is exceptionally important. These acidic gases are removed in the amine wash through chemical treatment with amines or alkanol amines. This application shows a convenient and precise analysis with the separation of various amines and standard cations on a column of the Metrosep C 6 - 250/4.0 type with subsequent direct conductivity detection.

Cation content in snow is greatly dependent on sampling site. Samples from remote areas are expected to exhibit lower cation concentrations. This application shows the analysis of a snow sample from an open field in an agricultural zone. Separation is performed on a microbore Metrosep C 6 - 100/2.0 column with direct conductivity detection. The relatively high ammonia content can be explained by animal husbandry in the vicinity of the sampling site.

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

As a result of the private burning of wood, concentrations of levoglucosan, mannosan and galactosan in the air are usually increased during the winter months. By contrast, a greater contribution of sugar components originating from biogenic sources can be anticipated in the summer months. Optimum separation and sensitivity of the saccharide markers that collect on air filters are achieved on the Metrosep Carb 2 - 150/2.0 column with subsequent pulsed amperometric detection.

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.

The combination of 850 Professional IC, 858 Professional Sample Processor, Dosino and MagIC NetTM software offers a variety of automated ion chromatographic sample preparation and calibration techniques available as an anion, cation or dual channel system. Calibration is straightforward and requires only one multi-ion standard.Inline calibration allows the calibration of any standard concentration in the ppt range by using one single stable standard solution at the ppb level. By using a preconcentration column and switching the valves one, two or more times different calibration concentrations at the ultra-trace level can be created with unprecedented reproducibility. The inline preconcentration technique uses a pre-concentration column and is ideally suited for trace analysis in complex matrices, especially when combined with matrix elimination. Besides facilitating the preparation of g/L to ng/L calibration graphs Metrohm`s intelligent techniques are capable of logical decision making. While Metrohm`s intelligent Partial Loop technique (MiPT) allows samples with a wide concentration range to be injected without previous manual dilution, the intelligent inline dilution technique, after the first sample injection, compares peak areas, calculates, if necessary, the dilution factor, dilutes and automatically re-injects the sample. The presented inline techniques allow the rationalization of the time-consuming, error-prone and cost-intensive manual preparation of standard solutions. They guarantee that the determined sample concentrations always lie within the calibration range. Higher sample throughputs as well as lower analysis costs and improved data reliability are achieved.

Harmful industrial flue gases like H2S and CO2 cause corrosion of pipes and damage the environment. Adding the correct amount of amines in scrubber solutions, e.g. ethanolamines and methylamines, will neutralize these gases («gas sweetening»). Non-suppressed cation analysis with direct conductivity detection is a straightforward and robust technique for the quantification of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA) via ion chromatography. Thanks to the high capacity of the Metrosep C 6 column, large volumes can be injected without compromising the peak shapes. The analytical technique can be used at laboratory scale but also for process analysis.

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.

As a result of the private burning of wood, concentrations of levoglucosan, mannosan, and galactosan in the air are usually increased during the winter months. On the other hand, one can expect a greater contribution of sugar components from biogenic sources during the summer months. An optimum separation and sensitivity of the saccharide markers that accumulate on air filters can be achieved on the Metrosep Carb 2 - 150/4.0 column with subsequent pulsed amperometric detection.

Beer wort is the liquid in which malt starch is converted enzymatically into sugars and is additionally flavored and preserved with hops. The most important sugars for beer brewing are maltose and maltotriose, which will be fermented into alcohol by the added brewing yeast. The composition of carbohydrates in wort is determined on a Metrosep Carb 2 - 250/4.0 column applying a Dose-in gradient to optimize resolution and duration of the analysis.

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.

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.

Ion chromatography trace analysis of anions in seawater is difficult, due to the high chloride concentrations. In contrast to chloride, nitrite, bromide and nitrate absorb UV radiation in the low wavelength range, thus enabling a UV detection of these three anions. This Application Note describes the separation on a column of the Metrosep Carb 2 - 100/4.0 type with a sodium chloride eluent. This minimizes the influence of the surplus chloride and enables low detection limits.

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.

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.

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

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.

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 maximum contaminant concentrations (Maximal Contaminant Level, MCL) of inorganic arsenic and selenium species in drinking water should not exceed 10 and 50 µg/L, respectively. Given that each of the two elements occurs in two oxidation levels – trivalent and pentavalent – a separation step is necessary prior to ICP/MS detection. This Application Note shows the simultaneous determination of the two arsenic (arsenite and arsenate) and selenium species (selenite and selenate). Separation takes place on the Metrosep Dual 3 - 100/4.0 column.

Ion chromatographic determination of sulfide in wastewater is performed using amperometric detection and an alkali eluent to ensure the stability of the sulfide. Measurements are performed in single-potential or direct current (DC) amperometric mode. It is the best-known and most sensitive amperometric measuring method and also provides, in addition to a high selectivity, a large selection of working electrodes.Sulfide determination is performed on a Metrosep A Supp 10 - 100/4.0 type column; a silver electrode is used as the working electrode.

Glycol solutions act as antifreeze agents and are often used as such in motor vehicles. Due to the toxicity of (mono)ethylene glycol (MEG), use is being increasingly expanded to the non-toxic propylene glycol. This Application Note presents the separation and quantification of the two glycols. Separation is performed on the Metrosep Carb 2 - 250/4.0 column. Due to the absence of chromophores and the low conductivity of the glycols, pulsed amperometric detection (PAD) is used to facilitate determination.Key words: ethanediol, propanediol

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.

This article describes a simple and sensitive method for chromium(VI) determination in children's toys. The solution to be analyzed is prepared in accordance with DIN EN 71. Not only VIS detection but also post-column derivatization using diphenylcarbizide are parts of this method. The procedure described here is suitable for the precise determination of hexavalent chromium in the single-digit ppt range and, in addition, fulfils without difficulty the limit value of 10 ppt prescribed by the EU directive 2009/48/EC.

In order to extract aluminum from bauxite, the aluminum ore is exposed with a caustic soda solution under pressure in the temperature range of 150 to 200 °C. Dilution and pH value setting are implemented by the addition of 170 mmol/L citric acid prior to calcium determination with ion chromatography in the Bayer caustic soda. Doing so establishes a pH value of 4.5 and prevents precipitation of aluminum hydroxide. The IC separation takes place on the Metrosep C 4 - 150/4.0 column with a citric acid eluent.

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.

The concentration of As(total) in zinc plant electrolyte is determined by anodic stripping voltammetry (ASV) on a lateral gold electrode in HCl electrolyte. Due to the high excess of zinc in the sample the deposition potential has to be adapted. A second potential approx. 100 mV more negative than the arsenic signal has to be applied to selectively oxidize interfering antimony. For sample preparation the sample was passed through a cation exchange column to reduce the concentration of zinc in the measuring solution.

This poster presents a straightforward ion chromatographic determination of HF, HNO3, short-chain organic acids and H2SiF6 in etching bath samples. Standard ions such as fluoride, nitrate, acetate and sulfate are determined via suppressed conductivity detection while dissolved silicate is spectrophotometrically detected in the same run after downstream post-column reaction (PCR) as molybdosilicic acid. Analytical results of several commercial HF-HNO3-H2SiF6 mixtures obtained by ion chromatography (IC) and titration showed good agreement, which confirms the applicability of the presented «dual» detection IC method for controlling the composition of acidic texturing baths.

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

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.

Biodiesel or green diesel is manufactured from fats and vegetable oils through ester interchange of the triglycerides they contain, during which glycerin accumulates as byproducts in both free and bonded forms. These accelerate fuel ageing and lead to deposits and clogged filters, which is why maximum permissible highest concentrations have been established (in the US in ASTM D6751 and in the EU in EN 14214).The two specifications prescribe the ion chromatography determination of free and bonded glycerin. This Note describes the determination with the aid of the Metrosep Carb 2 - 150/4.0 column in accordance with ASTM D7591.

Anions in diesel, especially biodiesel, may cause harmful deposits in the engine. Determination with ion chromatography requires the transfer of the diesel anions into an aqueous solution, injectable to the IC. A typical method to transfer the anions into water is via Inline Extraction with subsequent Inline Dialysis prior to the injection (see AN-C-101 for a respective analysis of cations). In the actual Matrix Elimination method, diesel diluted with isopropanol is injected into an isopropanol stream and passed through a preconcentration column. Isopropanol washes off the diesel, and a subsequent rinsing step with ultrapure water removes excess isopropanol.

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

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.

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

Metrohm`s intelligent Preconcentration Technique with Matrix Elimination (MiPCT-ME) excels in its capacity to perform automatic ion chromatographic determinations over 6 orders of magnitude. Crucial requirements for this are the system`s intelligence and the exact measurement of the sample volume. While the intelligence allows to compare results and take decisions, the dosing device takes over the high-precision liquid handling of even single-digit microliter volumes to the preconcentration column. By using only one analytical setup and without additional rinsing, samples containing both ultratraces and high concentrations can be analyzed.As the other Metrohm Inline Techniques, the MiPCT-ME technique presented reduces the workload, ensures complete traceability, is free of carryover effects and significantly improves accuracy and reproducibility of the results.

This poster demonstrates the feasibility of coupling a Metrohm IC system to a PerkinElmer NexION ICP-MS, operated under Empower 3 Software.Using a Metrosep Carb 2 column, the chromatographic separation of both species was achieved with a high resolution. Low background and high sensitivity allow determination in the low ng/L range.Optimal separation and full complexation of Cr(III) is already possible with EDTA concentrations from 40 μmol/L in low matrix solutions and may need to be increased depending on the sample matrix.Handling of the system was easy and user friendly. It was shown that speciation of Cr(III) and Cr(VI) can be carried out on this system utilizing a professional data system for acquisition, processing, and reporting.

According to the described method, NTA and EDTA can be determined in mass concentrations of 0.05 mg/L up to 25 mg/L in polluted water and wastewater.At first NTA and EDTA are converted to the corresponding Bi complexes by addition of Bi3+ ions at a pH value of 2.0. As these Bi complexes have significantly different peak potentials, they can be determined simultaneously by DP polarography. The interfering anions nitrite, sulfite, and sulfide are removed from the sample by acidification and purging. Interfering cations are removed by cation exchange; any NTA or EDTA heavy metal complexes present in the sample are disintegrated during this procedure. To remove surfactants and other organic components interfering with the analysis, the sample solution is run through a column filled with non-polar adsorber resin.

The simultaneous ion chromatographic determination of trace-levels of lanthanides (or lanthanoides) was achieved by using either direct non-suppressed conductivity detection or UV/VIS detection after post-column reaction (PCR) with arsenazo III at 655 nm. Conductivity detection under isocratic conditions resulted in an overall analysis time of approx. 70 minutes. In contrast, the determination of the lanthanides via gradient elution and subsequent spectrophotometric detection of the arsenazo III-lanthanide(III) complexes was performed within 22 minutes. Besides the outstanding analysis time, UV/VIS detection excelled by its enhanced selectivity and sensitivity and did not suffer from interferences by ubiquitous non-lanthanide impurities such as iron(III) or other transition metals. For both conductivity and spectrophotometric detection, the inclusion of sample preconcentration steps lowered the limit of detection (LOD) to the sub-ppb range.

Quality and process control of biofuels require straightforward, fast and accurate analysis methods. Ion chromatography (IC) is at the leading edge of this effort. Traces of anions in a gasoline/ethanol blend can accurately be determined in the sub-ppb range after Metrohm Inline Matrix Elimination using anion chromatography with conductivity detection after sequential suppression. While the analyte anions are retained on the preconcentration column, the interfering organic gasoline/bioethanol matrix is washed away.Detrimental alkali metals and water-extractable alkaline earth metals in biodiesel are determined in the sub-ppm range using cation chromatography with direct conductivity detection applying automated extraction with nitric acid and subsequent Metrohm Inline Dialysis. Unlike high-molecular substances, ions in the high-ionic strength matrix diffuse through a membrane into the low-ionic water acceptor solution. In biogas reactor samples, low-molecular-weight organic acids stem from the biodegradation of organic matter. Their profile allows important conclusions concerning conversion in the anaerobic digestion reaction. Volatile fatty acids and lactate can be accurately determined by using ion-exclusion chromatography with suppressed conductivity detection after inline dialysis or filtration.