Carrier gas changes for SimDist methods, such as ASTM Method D7213, can be easily implemented in your daily process. Using MXT-1HT SimDist columns and EZGC method translation software, helium-based SimDist methods can be easily translated to alternative carrier gases while maintaining ASTM Method D7213 requirements.
An Rxi-5ms column and a wool-packed inlet liner provide the stability and inertness needed for these basic, active analytes. Chromatography from a six-replicate system suitability analysis was well within normal acceptance criteria. USP tailing factors were approximately 1.00 for all analytes; retention times and area responses were very stable.
Dr. Radomír Čabala, Head of the Toxicology Department at the General University Hospital in Prague, presents work on the potential utility of GC-TOFMS analysis of cellular fatty acid methyl esters (FAMEs) in identifying clinically relevant bacteria.
Using the Van Deemter equation, it is clear that smaller LC column particle sizes yield better overall efficiencies, or less peak dispersion, across a much wider range of usable flow rates.
Two options for the analysis of PGIs in API have been developed by Merck and Restek to meet different laboratory needs. The first option is a fast method for the analysis of sulfonate esters on the Rxi-5Sil MS column. The second option is a comprehensive method for the analysis of both sulfonate esters and alkyl halides on the Rtx-200 column. Both methods require very little sample preparation, which helps increase laboratory productivity.
Dr. Werner Engewald discusses the phenomenon of cross-over, or changes in elution order following modification of the GC temperature program. This effect has been observed for decades but the physio-chemical background still is not well understood. In this article Dr. Engewald explores the theory and potential explanations for the cross-over phenomenon.
Numerous articles have been published on faster methods for gas chromatography (GC), yet uncertainty remains on how best to speed up separations. Here, Dr. Hans-Gerd Janssen clarifies the confusion surrounding fast GC and recommends a strategic approach based on 3 steps: 1) minimizing resolution to a value just sufficient, 2) maximizing the selectivity of the chromatographic system, and 3) implementing a method that reduces analysis time while holding resolution constant.
Hydrogen offers a number of benefits over helium as a carrier gas for gas chromatography. With basic safety measures in place, labs can safely use hydrogen for faster chromatography. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Proper sample evaporation in the injection port cannot be assumed. Principles governing evaporation are discussed. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
Discussion of the origins of the retention gap, a length of uncoated tubing used to focus large volume injections and prevent band broadening. By Dr. Konrad Grob, Kantonales Laboratory, Zurich
