New LC-MS Hardware…

Martin Perkins

10th June 2010

New Hardware…So Agilent were here at the end of last week and the beginning of this one, fitting the turbo pump upgrade and multimode ionisation source to allow me to get cracking with the Vitamin D work, we are looking to automate the protein precipitation of serum samples and then automate the SPE coupled to LC-QQQ…

…Vitamin D regulates the calcium and phosphorus levels in the blood by promoting their absorption from food in the intestines, and by promoting reabsorption of calcium in the kidneys, which enables normal mineralization of bone. It is also necessary for bone growth and bone remodeling. Recent studies identifying a role for vitamin D in prevention of cancer and cardiovascular disease have generated renewed interest in monitoring vitamin D levels in serum.

Vitamin D is produced in skin as D3, and by plants as D2, which is the form found in many nutritional supplements. Each form is metabolized by the liver to its 25-hydroxy derivative (25-OH) which is the active form. Both 25-OH D2 and 25-OH D3 are measured in blood and are collectively referred to as vitamin D in studies. It is critical that assays be capable of measuring total circulating vitamin D (D2 and D3). Traditionally, competitive binding experiments and immunoassays have been used to measure vitamin D. However, the cross-reactivity of the antibodies used in these assays can be less than 100%, and the results may not reflect total D2 and D3. More recently, LC-MS/MS has gained acceptance as the method of choice due to its ability to reliably quantify both vitamin D forms.

If you have an interest in this Vitamin D application please contact me at or post a comment below.