Development of a fast and sensitive UPLC-MS/MS method for quantitation of dilignols in aged garlic extract

A rapid, sensitive, and specific liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitation of the dilignols (–)-(2R,3S)-dihydrodehydrodiconiferyl alcohol (1), (+)-(2S,3R)-dehydrodiconiferyl alcohol (2), erythro-guaiacylglycerol-β-O-4′-coniferyl ether (3), and threo-guaiacylglycerol-β-O-4′-coniferyl ether (4) which have been previously identified as key antioxidants in aged garlic extract. After optimization of the MS conditions, the dilignols were analyzed by means of the multiple reaction monitoring, and their quantitation was validated. The calibration curves showed good linearities (R 2 > 0.999), and the LOQ were 0.1–5.9 ng/mL.