Ion Chromatography

Cefepime is a fourth generation cephalosporin (1). During preparation and storage, cefepime degrades by release of the N-methylpyrrolidine (NMP) side chain and opening of the beta-lactam ring. An NMP concentration increase will directly affect the potency of the active component of the drug. Therefore, it is critical to determine the amount of NMP in cefepime. The US Pharmacopeia (USP) monograph specifies the limit of NMP to <0.3% in cefepime hydrochloride and <1% in cefepime for injection (2,3). The latter is a dry mixture of cefepime hydrochloride and L-arginine. The current USP method uses cation-exchange chromatography with non-suppressed conductivity detection to determine the limit of NMP in cefepime. There are several disadvantages to this method, such as the ~3-4 h time required per injection, a lack of retention time stability for NMP in standard and sample solutions, and a lack of sensitivity. In this paper, we describe an improved method using a hydrophilic, carboxylate-functionalized cation..

This month's Technology Forum looks at the topic of HPLC/Ion Chromatography Focus and the trends and issues surrounding it. Joining us for this discussion is Chris Pohl, VP and Chief Science Officer at Dionex Corporation, Larry Tucker from Metrohm-Peak, and Yuichi Fusho of Shodex.

Ion chromatography (IC) is well suited for the analysis of a variety of inorganic and organic anions and cations. There is an additional dimension to an experiment using the technique as a result of the need to deal with changes in the ionic strength of the solution as the analyte materials are exchanged.

Ion chromatography (IC) is well suited for the analysis of a variety of inorganic and organic anions and cations.

Brian De Borba and Jeffrey S. Rohrer, Dionex Corporation

In this article, the authors describe a method based on the accelerated and automated extraction of hexavalent chromium from solid samples followed by ion chromatography analysis using spectrophotometric detection. The experiments were performed on different samples of sludge and soil.

Perchlorate salts are being used as rocket propellants in fireworks...

IC analysis of a cholinergic drug using suppressed-conductivity detection and eluent generation. (Dionex Corporation)

The authors demonstrate a new detection method for various anions and cations separated by ion chromatography and point out the main advantages of this method.

The authors demonstrate a new detection method for various anions of weak acids separated by ion chromatography and point out the main advantages of this method.

The authors developed an ion chromatography method to separate 31 cations in a single chromatographic run using inductively coupled plasma–mass spectrometry, liquid scintillation counting, and gamma counting. The high-level radioactive waste samples contained trace radionuclides in concentrations of only a few hundred disintegrations-per-minute-per-milliliter.