Progress of liquid chromatography-mass spectrometry in measurement of vitamin D metabolites and analogues

Abstract

Objective

Clinical testing for vitamin D nutritional status has experienced tremendous growth in the past several years, driven by research results linking various diseases with low serum 25-hydroxyvitamin D [25(OH)D] levels. Meanwhile, interest in the pathophysiological mechanism elucidation and pharmaceutical applications requires measurement of vitamin D metabolites and analogues. Liquid chromatography-mass spectrometry (LC-MS) has been increasingly utilized in these applications. In this work, our objective was to critically review the progress of LC-MS application in measuring vitamin D metabolites and analogues in biological fluids.

Methods

The LC-MS methods included were selected from those searchable in PubMed up to January 2010.

Results and Conclusion

LC-MS has unique advantages in measuring various vitamin D metabolites and analogues due to its flexibility, sensitivity, and specificity. Despite some controversies over serum 25(OH)D tests, LC-MS will be used for standardizing serum 25(OH)D assays using reference materials available from the National Institute of Standards and Technology.

Abbreviations 25(OH)D, 25-hydroxyvitamin D; 1,25(OH)2D, 1α,25-dihydroxyvitamin D; DBP, Vitamin D binding protein; VDR, Vitamin D receptor; t1/2, half-life time; 1OHD, 1α-hydroxyvitamin D; 24,25(OH)2D, 24R,25-dihydroxyvitamin D; OCT, 22-oxacalcitriol; ASMS, American Society for Mass Spectrometry; IS, Internal standard; SRM, Standardized reference materials; NIST, National Institute of Standards and Technology; DBS, Dried blood spots; CSF, Cerebrospinal fluid; LLOQ, Lower limit of quantification; SPE, Solid phase extraction; LLE, Liquid-liquid extraction; PPE, Protein precipitation extraction; DMEQTAD, 4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyl]-1,2,4-triazoline-3,5-dione; PTAD, 4-phenyl-1,2,4-triazoline-3,5-dione; UVB, Ultraviolet B radiation; LC-MS, liquid chromatography-mass spectrometry; LC-SMS, liquid chromatography-single mass spectrometry; LC-TMS, liquid chromatography-tandem mass spectrometry; APCI, atmospheric pressure chemical ionization; ESI, electrospray ionization