Procedures were developed for collecting and isolating carbonyls from such complex mixtures as oximes, and for subsequent chromatographic analysis of the oxime mixture. The isolation procedure was based on the weak-acid properties of oximes, which permit separation from hydrocarbons and other neutral materials by extraction with pentane. Retention of oximes in the basic phase was improved by the addition of alcohols and by extraction at low temperatures. Chromatographic analysis of oximes was accomplished using an all-glass system. Oximes were decomposed to nitriles by hot metal surfaces but were stable in glass equipment that had been cleaned to remove heavy metal oxides. The most satisfactory chromatographic column had a glass tube filled with glass-bead support that was coated with a polyglycol liquid phase. In chromatograms, most aliphatic aldoximes showed double chromatographic peaks that were due to the syn and anti isomers. These were identified, and the isomer peak ratio was shown to be affected by steric interference. Phenols were recovered in the isolation procedure and could be analyzed in the same chromatographic system. Applications in diesel- and gasoline-engine exhaust are discussed.