Extractive hydrogenation: A new and versatile technique broadening gas chromatography applications

Article abstract of DOI:10.1021/ac00079a039

A new technique, "extractive hydrogenation", is combined with gas chromatography (GC) to analyze organic including biological samples. In this method, the sample (or an extract thereof) is subjected to intense hydrogenation under aqueous conditions in the presence of excess (in terms of mass) palladium/carbon catalyst. Products with a saturated hydrocarbon framework result, for example, as alcohols, the larger of which adsorb onto the carbon of the catalyst. These larger products are separately recovered by extracting the washed catalyst with an organic solvent and then detected by GC. Here, the GC was fitted with a flame ionization detector (FID) or an electron impact mass spectrometer (EI-MS). Detection in this way (H₂-GC) of the following trace analytes was achieved: (a) 100 μg of an (acetylamino)fluorene-deoxyguanosine DNA adduct spiked into 1 mg of DNA; (b) 1.5 μg of novobiocin, an antibiotic, spiked into 15 mL of milk (followed by extraction prior to H₂-GC); and (c) 1 mg of 4-aminobiphenyl, a carcinogen, spiked into 150 mg of hemoglobin (followed by hydrolysis prior to H₂-GC). The technique gave somewhat different GC-FID chromatograms for Escherichia coli and Enterococcus bacteria. Unlike pyrolysis (similarly used prior to GC), which tends to convert a biological sample into a char, the hydrogenation technique turns the sample into a clear aqueous solution. Most importantly, the method brings a broad variety of organic-containing samples in a simple way into the scope of GC/EI-MS with its computerized library of spectra.