A quantitative gas chromatographic method for the analysis of multi-phase product mixtures from the catalytic oxidation of cyclohexane is described. The phases are made homogenous by the addition of sufficient tetrahydrofuran solvent and then all active-H containing compounds are silylated. The method is applicable to low levels (34%) of tetrahydrofuran and acetic acid. The reproducibility for major components (30 results) is good to <±0.25%. This method can also be used for the qualitative identification of phenol, cyclohexanediols, formic, valeric, caproic, benzoic, oxalic, and malonic acids.