GC-MS analysis of the (S)-2-phenylbutyryl derivatives of a racemic (RS)-1,2-propanediol standard, a pure (S)-1,2-propanediol standard, and a sample from a resting-cell experiment of A. tertiaricarbonis wild-type strain L108 incubated on 2-propanol. (A) Total ion chromatogram signals; (B) mass spectra of peaks occurring in the total ion chromatograms of the sample and the racemic standard at 37.9 min, representing the (S)-2-phenylbutyryl derivative of (R)-1,2-propanediol.