title: Improved GC/MS method for quantitation of n-alkanes in plant and fecal material.
abstract: A gas chromatography-mass spectrometry (GC/MS) method for the quantitation of n-alkanes (carbon backbones ranging from 21 to 36 carbon atoms) in forage and fecal samples has been developed. Automated solid-liquid extraction using elevated temperature and pressure minimized extraction time to 30 min per sample as compared to more than 24 h for traditional GC-flame ionization detection methods that use saponification and liquid-liquid extraction. Extraction solvent requirements were also minimized to 10 mL per sample. Under optimal conditions, complete method recoveries, including extraction efficiency, were greater than 91%. The linear dynamic range was 5 to 100 nmol injected onto the column, with a limit of quantitation of 5 nmol. Intra-assay coefficients of variation for the analysis of annual ryegrass (Lolium rigidum), subterranean clover (Trifolium subterranean), and bovine feces ranged from 0.1%-12.9%, where lower concentrations of n-alkane produced a higher degree of imprecision. The reported GC/MS method permits simple, rapid, and precise quantitation of n-alkanes in plant and fecal material and reduces reagent and labor requirements.
authors: Forage-Animal Production Research Unit, USDA-ARS, Lexington, Kentucky 40546, USA.
authors: Lori L
authors: LL
authors: Smith
authors: James R
authors: JR
authors: Strickland
mesh_terms: D000473:Alkanes / Q000032:analysis*; D000818:Animals; D004032:Diet; D005243:Feces / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D008129:Lolium / Q000737:chemistry; D010944:Plants / Q000737:chemistry*; D012680:Sensitivity and Specificity; D029921:Trifolium / Q000737:chemistry
chemical_list: D000473:Alkanes