Fast, Sensitive, Acetonitrile Free Vitamin D Assay

A new method for low-level determination of the 25-mono-hydroxy-metabolites of vitamin D2 and D3 in plasma has been developed by Spark Holland.
The assay is completely acetonitrile free avoiding problems associated with the current acetonitrile shortage. Quantitation levels of around 1 ng/mL are reported using the Symbiosis™ system for HPLC with integrated Solid Phase Extraction linked to an Applied Biosystems API 4000 Mass Spectrometer. The assay involves almost no manual handling: plasma samples are diluted with a newly developed protein disrupting buffer which also contains the internal standard. Samples are then placed in the autosampler for direct injection into the SPE-LC-MS/MS system.

The method shows excellent linearity, precision and carry-over and runs in only four minutes, including SPE. Low levels of vitamin D have been associated with osteoporosis, diabetes, hypertension and cancer. The new acetonitrile free vitamin D assay is therefore likely to be of significant benefit, in terms of speed, cost effectiveness and convenience to clinical and clinical research laboratory environments. An innovative development from Spark, the vitamin D assay is the latest example of the high assay quality and sensitivity achieved by dedicated on-line SPE-LC-MS/MS systems. High-resolution SPE cartridges and precise SPE process controlenable highly efficient sample preparation and concentration. Combined with direct elution into LC-MS/MS systems, high assay performance is achieved as well as maximum assay automation.