Accurate analysis of biodiesel FAME in jet fuel is critical for ensuring that contamination levels do not exceed allowable limits. Method IP 585 is commonly used for this analysis and here we perform the method using a Stabilwax column and GC-MS in SIM mode. Method calibration curve criteria were met and good recoveries of the total FAME content in jet fuel were obtained.
Sulfur compounds in fuel streams can damage equipment and reduce BTU values. Sulfinert sample cylinders are significantly more inert than stainless steel cylinders and assure sample integrity during collection, transportation, and storage.
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.
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.
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 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. 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.
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.
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
