Using Alternative Carrier Gases with Accelerated ASTM D2887 Simulated Distillation Analysis

Using Alternative Carrier Gases with Accelerated ASTM D2887 Simulated Distillation Analysis

ByAudrey Crater

ASTM Method D2887 now allows for alternate carrier gases, so hydrogen or nitrogen can replace helium carrier gas for simulated distillation. Here, we show that with an MXT-1HT SimDist column and Restek’s EZGC online method translator existing methods using helium can be easily converted to either hydrogen or nitrogen carrier gas. Because retention times are preserved with proper method translation, there are minimal changes to peak identification tables which significantly simplifies method validation.

Assaying Local Anesthetics by GC/FID

ByAudrey Crater

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.

Alternative Carrier Gases for ASTM D7213 Simulated Distillation Analysis

Alternative Carrier Gases for ASTM D7213 Simulated Distillation Analysis

ByAudrey Crater

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.

Two Options for Analyzing Potential Genotoxic Impurities in Active Pharmaceutical Ingredients

ByAudrey Crater

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.

Characterizing Cellular Fatty Acid Methyl Ester (FAME) Profiles to Identify Bacteria Using Gas Chromatography

ByAudrey Crater

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.

Retention Cross-over Phenomenon in Gas Chromatography — Can the Mystery be Revealed?

ByAudrey Crater

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.

Achieving Faster GC

ByAudrey Crater

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.