Analysis of wax ester molecular species by high performance liquid chromatography/atmospheric pressure chemical ionisation mass spectrometry.

摘要: Abstract High chromatographic resolution of wax esters (WEs) was achieved by non-aqueous reversed-phase liquid chromatography on a Nova-Pak C18 column optimising the acetonitrile/ethyl acetate mobile phase gradient. The retention behaviour WEs studied in this system. eluted according to their equivalent carbon number (ECN) values; within group with identical ECN, most unsaturated species tended elute first. isobaric different positions ester moiety were separated from each other whenever lengths chains sufficiently different. methyl-branched at shorter times than straight-chained analogues, and among depended position branching. analytes detected atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) using data-dependent scanning. provided simple full-scan spectra abundant protonated molecules low-intensity fragments. Collision-induced dissociation (CID) promoted identification WE molecular species. responses found be dependent double bonds alkyl-chain length; limits detection ranged 20 μmol/L 200 nmol/L. HPLC/APCI-MS applied for analysis isolated honeycomb beeswax, jojoba oil human hair. Good agreement between reported results literature data achieved, several novel polyunsaturated also being found.