Typically, 1,4-dioxane and nitrosamines are analyzed in drinking water following separate extraction and analysis procedures, such as Methods 521 and 522. However, here we present a combined method that uses large volume splitless injection and GC-MS (SIM) to meet low part-per-trillion detection limits for these compounds in a fraction of the time required when running separate methods.
n-Octane on Res-Sil C packing provides excellent, reproducible separations of volatile hydrocarbons in petroleum products, including the difficult-to-separate saturated and unsaturated C4 compounds. An OPN on Res-Sil C column separates C1-C5 hydrocarbons in half the time required by alternative columns.
The results of a simulated distillation analysis are vitally important to the operation of refineries globally. For the analysis of petroleum samples within the boiling point range from 55.5 ˚C to 538 ˚C, ASTM D2887 is a standard method that has been accepted and is used industry-wide. This application note will demonstrate how a creative use of the Restek GC Accelerator oven insert kit can permit analysts using Agilent 6890/7890 GCs with 100/120 V ovens to successfully migrate from D2887’s slower Procedure A conditions to the accelerated Procedure B conditions without new instrumentation or software, resulting in a 9-minute analysis time that meets all method requirements.
Robust Rtx-DHA columns are highly stable and can be run with hydrogen carrier gas under accelerated conditions. The hydrogen-based method for detailed hydrocarbon analysis shown here is twice as fast as traditional approaches, which allows labs to process samples faster and make more profitable decisions during product blending.
In process GC analyses, this material offers unique selectivity for the difficult-to-separate saturated and unsaturated C4 hydrocarbons, eluting cis-2-butene before 1,3-butadiene. Innovative bonding chemistry assures batch-to-batch reproducibility, excellent thermal stability, and long column life.
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.
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.
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.
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.
