Analysis of FAMEs in Biodiesel Fuel: Pro EZGC Modeling Software Ensures Proper Column Selection

Analysis of FAMEs in Biodiesel Fuel: Pro EZGC Modeling Software Ensures Proper Column Selection

VonAudrey Crater

Polar columns were evaluated for the analysis of fatty acids methyl esters (FAMEs) in finished B100 biodiesel according to method EN 14103 (2011). Using Restek’s Pro EZGC chromatogram modeler, a high cyano phase Rt-2330 column and a polyethylene glycol phase FAMEWAX column were compared. The modeling software predicted an unacceptable coelution between the internal standard (C19:0 FAME) and FAME C18:2 when using the Rt-2330 column. However, the modeler also predicted that the FAMEWAX column would separate all the compounds of interest, which was demonstrated empirically. In addition, the results on the FAMEWAX column showed excellent repeatability for both total FAMEs and the linolenic acid methyl ester component.

Using Alternative Carrier Gases with Accelerated ASTM D2887 Simulated Distillation Analysis

Using Alternative Carrier Gases with Accelerated ASTM D2887 Simulated Distillation Analysis

VonAudrey 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.

GC Analysis of Total Reduced Sulfurs at ppbv Levels

VonAudrey Crater

Ultra-low bleed and exceptional inertness assure complete separation of sulfur compounds (hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, mercaptans) on our new column, with excellent peak shapes and reliable quantification at ppbv levels. A Sulfinert treated sampling/transfer system assures no adsorption losses of these very reactive compounds.

Alternative Carrier Gases for ASTM D7213 Simulated Distillation Analysis

Alternative Carrier Gases for ASTM D7213 Simulated Distillation Analysis

VonAudrey 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

VonAudrey 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

VonAudrey 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.

Achieving Faster GC

VonAudrey 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.

Overcoming the Effects of Highly Organic Protein Precipitation Extracts on LC Peak Shape Using Direct Injection

VonAudrey Crater

Protein precipitation is frequently used to minimize matrix impact when analyzing biological samples. However, the effects of highly organic protein precipitation sample extracts on LC peak shape can negatively impact accurate quantification. Dilution or further sample preparation steps are often used to minimize these effects; however, here we show that direct injection of sample extracts is a viable option that can be used to prevent peak distortion, while avoiding the time and variability associated with additional sample preparation.