Advances in determination of vitamin D related compounds in biological samples using liquid chromatography–mass spectrometry: A review

The measurements of the serum/plasma concentrations of vitamin D metabolites are widely used for the diagnostic assessment and follow-up of several diseases, such as chronic renal failure and osteoporosis. These metabolites have usually been measured by protein binding assays, such as radioimmunoassay and radioreceptor assay. Although these techniques will doubtless continue to be the methods of choice for routine use in the clinical field, their specificity and accuracy are sometimes poor due to interference from other metabolites and lipids. Among the alternative methods, liquid chromatography (LC) coupled with mass spectrometry (MS) has been used for the analysis of these metabolites and even synthetic vitamin D analogues (therapeutic agents) due to its sensitivity and selectivity. This article reviews recent advances in the determination of vitamin D metabolites and related compounds in biological samples using LC–MS.