Quantification of Trans‐ and Cis‐Vitamin K1 Isomers in Human Plasma by a Rapid and Sensitive LC–MS/MS Method With Surrogate Matrix

A rapid and specific liquid chromatography-tandem mass spectrometry method with a wide linear range was developed and validated for the simultaneous quantification of Vitamin K1 (VK1) trans- and cis- isomers in human plasma. Bovine serum albumin solution (15%) served as a surrogate matrix for preparing the calibrators to establish the quantitative curves. After liquid-liquid extraction, VK1 trans- and cis- isomers in plasma samples were separated on a ChromCore C30 column (15 cm × 4.6 mm, 3 μm) using water: methanol: acetonitrile: formic acid (5:80:20:0.1, v/v/v/v) as the mobile phase. Mass spectrometry detection was performed in positive ion mode with atmospheric pressure chemical ionization (APCI) interface by multiple reaction monitoring (MRM) method. The calibration curves were linear over the range of 0.400-6000 ng/mL for the trans-isomer and 0.400-1200 ng/mL for the cis-isomer (r ≥ 0.994). The intra- and inter-day precision was below 9.55% in terms of relative standard deviation (RSD%) and the accuracy was within ±11.24% in terms of relative error (RE%). The selectivity, sensitivity, extraction recovery, matrix effect, dilution reliability, and stability met the acceptable criteria. The reliable LC-MS/MS method for concurrent detection of VK1 trans- and cis- isomers was successfully employed in a pharmacokinetic study in healthy Chinese volunteers after oral administration of 10 mg VK1.