Direct Chromatographic Analysis of Milk a

SUMMARY Some organic chemical compounds were detected in milk by a simple, direct chromatographic analysis of head‐space vapors. After modifying the head‐space gas‐sampling technique by saturating the aqueous solution with sodium sulfate and increasing the amplification of the chromatographic hydrogen flame detector electrometer, some organic compounds were detected at less than 0.1 ppm concentration in milk. Samples of fresh and stored raw milk, with and without off‐flavors, were analyzed successfully. Some volatile chemical compounds developed during storage at 2°C. Off‐flavors were characterized by the development of certain chromatographic peaks. Chromatograms were recorded for analyses of rancid, oxidized, sunlight‐oxidized, and high‐acid milks. A number of chromatographic peaks were characterized as carbonyl from their reaction with hydroxylamine. Acetaldehyde, propionaldehyde, acetone, and 2‐butanone were identified. An indication of the concentration of some of these peaks was obtained by analyzing solutions of 0.1 ppm acetaldebyde, propionaldehyde, and 2‐hexanone added to water and to milk.