Determination of vitamins K
1 , MK-4, and MK-7 in human serum of postmenopausal women by HPLC with fluorescence detection.
J Clin Lab Anal 2018;
32:e22381. [PMID:
29333616 DOI:
10.1002/jcla.22381]
[Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/14/2017] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND
New high-performance liquid chromatography (HPLC) method was developed for the determination of vitamin K1 and two forms of vitamin K2 (MK-4 and MK-7) in human serum, and the levels of vitamin K were determined in 350 samples of postmenopausal women.
METHODS
Vitamin K was determined by HPLC with fluorescence detection after postcolumn zinc reduction. The detection was performed at 246 nm (excitation) and 430 nm (emission). The internal standard and 2 mL of ethanol were added to 500 μL of serum. The mixture was extracted with 4 mL of hexane, and solid phase extraction was then used.
RESULTS
The HLPC method was fully validated. The intra- and interday accuracy and precision were evaluated on two QC samples by multiple analysis, and CV were less than 10%. The limit of quantification for MK-4 was found at 0.04 ng/mL, for K1 0.03 ng/mL, and for MK-7 0.03 ng/mL. The mean recoveries of the corresponding compounds were 98%-110%. Serum levels of MK-4, K1 , and MK-7 in postmenopausal women with osteoporosis were 0.890 ± 0.291 ng/mL, 0.433 ± 0.394 ng/mL, and 1.002 ± 1.020 ng/mL, respectively (mean ± SD). Serum levels of MK-4, K1 , and MK-7 in postmenopausal women without osteoporosis were 0.825 ± 0.266 ng/mL, 0.493 ± 0.399 ng/mL, and 1.186 ± 1.076 ng/mL, respectively (mean ± SD).
CONCLUSION
New HPLC method for the determination of vitamins K1 , MK-4, and MK-7 in serum was evaluated and validated. This method is highly specific and sensitive with the low limit of quantification.
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