Abstract Reversed phase liquid chromatography–atmospheric pressure chemical ionization mass spectrometry (RP-HPLC/MS-APCI) was used to analyze both synthetic triacylglycerols (TAG) having 1–3 branched fatty acids (FA) in the molecule, and natural TAG prepared by precursor directed biosynthesis from valine, leucine and isoleucine and the corresponding branched short-chain acids in cultivations of Rhodococcus erythropolis. The technique ...