A process is claimed for extraction and conc. on an adsorbent cartridge of volatile prods. (I) (esp. alkanes, e.g. ethane and pentane) formed in the peroxidation of polyunsaturated fatty acids, for analysis of (I) after thermal desorption and gas chromatography (GC). The novel features are that (I) are extracted and conc. under an atmos. protected against all exogenous contamination; the cartridge is placed in a sealed storage envelope to keep the extract free of contaminants; the envelope is supplied to a location for thermal desorption and analysis by GC; and analysis is carried out. USE/ADVANTAGE - The process is esp. used (claimed) for non-invasive analysis in an ambulatory patient of (I) formed by peroxidation of cell membrane polyunsatd. fatty acids (esp. linoleic and linolenic acid), where the (I) is eliminated from the body transdermally or in exhaled air. Determn. of such (I) is useful in determn. of cellular ageing, e.g. due to free radicals or exposure to radiation. (I) concns. are also indicative of numerous chronic or acute diseases (e.g. cancer, atherosclerosis, emphysema, diabetes, Alzheimer's disease, AIDS or arthritis); e.g. the pentane content of exhaled air in renal haemodialysis patients doubles after dialysis. The process can also be used in the food industry (e.g. for monitoring rancidity of oils or ageing of wines), or applied to cosmetics, cell cultures or isolated organs. (I) can be determined without problems of contamination; invasive procedures and heavy appts. The process is widely applicable, and can use commercially available adsorbent cartridges such as 'Carbotrap' (RTM; based on active carbon).
