[Simultaneous determination of 25-hydroxyvitamin D and vitamin K_1 in serum by ultra-performance liquid chromatography-tandem mass spectrometry].

To establish a method for analysis of 25-hydroxylvitamin D_2(25(OH)D_2), 25-hydroxylvitamin D_3(25(OH)D_3)and vitamin K_1 in serum by ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS), which can be applied in diagnosis of vitamin deficiency and estimation on the nutritional status of people.Serum samples mixed with d_6-25(OH)D_3, d_7-vitamin K_1(internal standard)were precipitated with acetonitrile and extracted with n-hexane. The sample solution was separated using BEH C_(18) column(2. 1 mm×100 mm, 1. 7 μm) with gradient elution using methanol-water containing 0. 1% formic acid as mobile phase. The target molecule was detected in positive electrospray ionization(ESI~+) and multiple reaction monitoring.The concentration of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 showed good linearity in the range 5. 0-75. 0 ng/mL, 2. 0-81. 5 ng/mL and 0. 3-12. 0 ng/mL, respectively, with the correlation coefficients greater than 0. 995. The limits of detection(LOD) of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 were 1, 0. 25 and 0. 1 ng/mL, and the limits of quantification(LOQ) for 25(OH)D_2, 25(OH)D_3 and vitamin K_1were 3, 0. 75 and 0. 3 ng/mL, respectively. The recoveries of three levels in the matrix were 98. 5%-104. 3%, the relative standard deviation(RSD) were all less than 5. 0%(n=6).An UPLC-MS/MS method for analysis of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 in serum is sensitive, rapid, accurate and suitable for the nutritional surveillance of vitamin D and K_1 in the population.