Problems in Commercial Kits of 25-Hydroxy Vitamin D and the Development of Simple, Robust and Faster HPLC Method.

Vitamin D is a lipid-soluble compound that plays a key role in bone mineral metabolism. The commercial current kits and several published assay methods (High-performance liquid chromatography (HPLC) and Immunoassay) are complicated due to the use of multiple reagents, larger sample volume, high backpressure, longer extraction time, evaporation under nitrogen after extraction, significant interference and antibody cross-reactivity. Here we report a new HPLC method for the determination of 25-hydroxyvitamin D2 (25-OHD2) and 25-hydroxyvitamin D3 (25-OHD3) that is simple (no evaporation), rapid (10-minute run time) and robust.

Accurate determination of Biotinidase activity in serum by HPLC and its utilization as second tier test for the confirmation of initial positive newborn screening results.

Diagnosis of Biotinidase deficiency (BTD) is extremely important to avoid several neurodevelopmental problems in early childhood. Colorimetric and fluorometric methods lack specificity and selectivity due to several interferences resulting in a high number of false positive results. We developed an HPLC method for BTD activity in serum with fluorescent detection.

Determination of nicotinamide and 4-aminobenzoic acid in pharmaceutical preparation by LC.

A rapid, precise and time saving high performance liquid chromatographic method has been developed and validated for the simultaneous determination of nicotinamide and 4-aminobenzoic acid in pharmaceutical preparation. The method involves isocratic elution of mobile phase through column in a reverse phase chromatography with UV detection at 254 nm. The ranges of quantification for nicotinamide and 4-aminobenzoic acid were 11-34 microg ml(-1) and 37-113 microg ml(-1), respectively.