Abstract An analytical method using gas chromatography isotope ratio mass spectrometry (GC-IRMS) combined with solid phase micro-extraction (SPME) was developed to measure the δ 13C values of six typical volatiles commonly occurring in wine (isoamyl acetate, 2-octanone, limonene, 2-phenylethanol, ethyl octanoate and decanoate) for first time. SPME selected a divinylbenzene/carboxen/polydimethyl...

Compound-specific isotope analysis (CSIA) by isotope ratio mass spectrometry (IRMS) following on-line combustion (C) of compounds separated by gas chromatography (GC) is a relatively young analytical method. Due to its ability to measure isotope distribution at natural abundance level with great accuracy and high precision, GC-C-IRMS has increasingly become the method of choice in authenticity ...

This paper discusses some of the recent improvements in instrumentation used for stable isotope tracer measurements in the context of measuring retinol stores, in vivo. Tracer costs, together with concerns that larger tracer doses may perturb the parameter under study, demand that ever more sensitive mass spectrometric techniques are developed. GCMS is the most widely used technique. It has hig...

The essential oils of wintergreen and birch are composed primarily methyl salicylate. Because this compound can easily be synthesized, frequently adulterated. By using Gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry (GC-C/P-IRMS) in conjunction with TC/EA-IRMS, GC-FID, GC-MS, 14C radiocarbon dating, criteria will established that used to distinguish authentic natural fro...

The administration of synthetic steroid copies is one of the most important issues facing sports. Doping control laboratories accredited by the World Anti-Doping Agency (WADA) require methods of analysis that allow endogenous steroids to be distinguished from their synthetic analogs in urine. The ability to measure isotope distribution at natural abundance with high accuracy and precision has i...

Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is increasingly applied to food and metabolic studies for stable isotope analysis (δ(13) C), with the quantification of analyte concentration often obtained via a second alternative method. We describe a rapid direct transesterification of triacylglycerides (TAGs) for fatty acid methyl ester (FAME) analysis by GC-C-IRMS d...

Accurate determinations of stable isotope ratios require a calibration using at least two reference materials with different isotopic compositions to anchor the isotopic scale and compensate for differences in machine slope. Ideally, the delta values of these reference materials should bracket the isotopic range of samples with unknown delta values. While the practice of analyzing two isotopica...

Rationale The hydrogen isotopic composition of lipids (?2Hlipid) is widely used in food science and as a proxy for past hydrological conditions. Determining the ?2H values large, well-preserved triacylglycerides other microbial lipids, such glycerol dialkyl tetraether (GDGT) thus widespread interest but has so far not been possible due to their low volatility which prohibits analysis by traditi...

Isotope ratio analysis of total organic carbon (TOC) is well-established for the study rivers, lakes, and oceans. Similarly, these aquatic systems are routinely surveyed to quantify natural anthropogenic compounds pollutants, including such things as pharmaceuticals, illicit drugs, phthalates. We merged two approaches demonstrate compound specific isotope (CSIA) on four phthalate esters non-tar...