Validation of Automated Liquid-Liquid Extraction of 25-hydroxy vitamin D from whole blood or spiked BioCell material (artificial blood) samples using VERSA Workstation, and its determination by LC/MS
Introduction:
Vitamin D is important to bone health and its deficiency is associated with osteoporosis and rickets, cardiovascular disease, diabetes, and autoimmune disorders to depression, stroke, chronic pain, osteoarthritis, and many forms of cancer. Measurement of circulating levels of 25-hydroxy vitamin D is also important in the diagnosis of intestinal mal-absorption and vitamin D deficiency or intoxication in humans. Research has indicated that vitamin D deficiency is widespread in the general population. This has led to exponential growth in clinical diagnosis tests for 25-hydroxyvitamin D also known as [25(OH)D] in blood serum. However, this form of vitamin D in the blood has a half-life of four to six hours, and is tightly bound to a transport protein in circulation. Therefore, testing methods must process samples rapidly, and must be capable of dislodging 25(OH)D from its carrier proteins.
Several methods are available to assess vitamin D sufficiency through measurement of serum 25(OH)D. Since there are two forms of vitamin D that contribute to the overall status of an individual (one derived primarily from vitamin D produced in the skin, and the other from diet or supplementation), it is important that both forms be measured equally. Antibody (ELISA) or other protein-binding assays are available, but proficiency testing and comparison studies have raised questions about the ability of most existing assays to accurately measure the different forms of 25(OH)D, and by extension, the total vitamin D value that these assays report. Some larger laboratories have developed assays using LC-MS/MS tandem mass spectrometry or HPLC. However, manual sample preparation methods for such assays are very cumbersome.
Aurora’s VERSA™ LLE Workstation has been validated for the organic solvent extraction of 25(OH)D from blood serum using liquid-liquid extraction (partition chromatography). Validation data is presented in this technical-note.
Results:
Reliable reproducibility of peak height data from the unit suggests that biomolecules like 25(OH)D can be effectively extracted using this automation within acceptable values. Moreover, the automated process takes 60 minutes for a set of 96 samples with no detectable cross contamination. The extraction process took approximately 17 minutes less than the manual procedure.
Conclusion:
The process of liquid-liquid extraction assisted by automation using the VERSA™ LLE Workstation was shown to be a successful alternative to the cumbersome separatory funnel for isolation of such compounds.
|
