Liming Peng | Authors


Enantiomeric Separation of Proton Pump Inhibitors Using Polysaccharide-Based Chiral Stationary Phases in Reversed-Phase HPLC Conditions

The chiral analysis and purification of proton pump inhibitors (PPIs) has become a popular topic as more of these drugs fall out of patent protection each year. Due to their wide range of enantiomeric selectivity, a set of polysaccharide-based chiral stationary phases (CSPs) was screened to identify methods for the successful enantioseparation of four benzimidazoles; rabeprazole, lansoprazole, omeprazole, and pantoprazole.

A Simplified Approach to Optimize SPE Method Development with Downstream LC–MS Analysis Allowing 100% Organic, Basified Injection Solvents

Automated solid-phase extraction (SPE) has been used extensively with liquid chromatography–tandem mass spectrometry (LC–MS-MS) to facilitate high-throughput analysis in the pharmaceutical, diagnostic, and forensic toxicology areas. In this work, we demonstrate the use of a systemized approach to SPE method development and LC–MS-MS analysis. This approach provides dramatic savings in analysis time and takes advantage of new innovations in high performance liquid chromatography (HPLC) columns to provide the cleanest extracts for LC–MS injection.

High-Speed Analysis of b-Blockers and Metabolites in Human Plasma by LC–ESI-MS-MS with High-pH Mobile Phase

Beta-blockers are basic compounds that contain a secondary amino group in their structure. The amino substituents are typically an isopropyl group and a larger chain with a hydroxyl group in the beta position from the nitrogen atom (Table I). The simultaneous analysis of ?-blockers in biological samples is meaningful, and is made possible by the similarities in their structure. Gas chromatography (GC)–mass spectrometry (MS) has been the most used technique for their identification and quantification (4–6). However, most ?-blockers are nonvolatile and thus require derivatization via a cumbersome and time-consuming process before GC–MS analysis. In recent years, liquid chromatography (LC) coupled with mass spectrometric detection has evolved as the method of choice for drug analysis in the pharmaceutical, clinical, and forensic toxicology areas (4–8). In contrast to GC–MS, LC–MS-MS generally does not require derivatization and offers superior sensitivity. Moreover, due to the high specificity offered by LC–MS-MS, baseline chromatographic resolution often is not required, allowing for fast analysis in high-throughput environments.