Applications

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

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.

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

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.

Determination of trace levels of cations and amines in hydrogen peroxide is important in quality determination of high-grade semiconductor chemicals. In particular, some manufactures look for 1 ppb trimethylamine or less in hydrogen peroxide samples. Ion chromatography after MiPCT-ME* with conductivity detection after sequential cation suppression is applied.

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.

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.

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

The poster describes how different suppressors (MSM and MCS) work and mentions possible applications.

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