Quantitative Analysis of 25-OH Vitamin D Using Supported Liquid Extraction and Liquid Chromatography - Mass Spectrometry

Abstract

We report a low sample vol. LC/MS method for 25OH Vitamin D anal. The method requires only 40 μl serum, is fully automatable, fast and sensitive. The method was successfully implemented for clin. anal. of infants for vitamin D deficiency. The 6 min method has a sensitivity range from 2 to 100 ng/mL. A 3 min method was validated from 5 to 100 ng/mL range. Fast anal., low sample vol. and high sensitivity were achieved by combination of supported liq. extn. sample prepn., UHPLC chromatog. and fused-core chromatog. column for sepn., and highly sensitive mass spectrometry for detection. We emphasize the importance of sample prepn. quality for rugged LC/MS anal. Using SLE-based sample prepn. we successfully used only 40 μl of serum while achieving a LLOQ of 2 ng/mL. We found from assayed samples, that 3-12 mo old infants were not Vitamin D deficient, compared to adults. The av. level of 25(OH)D3 in infants was 57.3 compared to 38.0 ng/mL for adults in a Bronx, NY patient population. [on SciFinder(R)]