Removal of volatile flavour constituents from foods prior to analysis by gas‐liquid chromatography

Volatile aroma constituents were removed from cooked chicken by vacuum distillation at 35°, followed by extraction of the aqueous distillate with ethyl chloride and concentration into a small volume of isooctane, to facilitate their analysis by gas‐liquid chromatography. In an alternative procedure the meat, powdered in liquid nitrogen, was extracted with ethyl chloride, and the volatiles were separated from the lipid extract by vacuum distillation and similarly concentrated for application to the column. The second method gave the better extraction, particularly for components of higher boiling point. Optimum sensitivity and reproducibility were achieved by transfer of the whole of a concentrated extract of the volatiles from e.g. 100 g meat in 1–3 ml of solvent on to a column previously cooled to ‐60° to ‐70°, followed by rapid heating to 31° and subsequent temperature programming to 200° in the usual way. Compounds of chain length C4 to C15 (at least) could be quantitatively transferred to the column and determined by this procedure.