Determination of serum vitamins 25-OH-D2 and 25-OH-D3 with liquid chromatography-tandem mass spectrometry using atmospheric pressure chemical ionization or electrospray source and core-shell or sub-2 μm particle columns: a comparative study.

Objective: Develop a simple LC-MS-MS method for determination of 25-hydroxymetabolites of vitamin D2 and D3 in serum.

Design And Methods: 0.1 mL serum was mixed with 0.

Simultaneous LC-MS-MS determination of cyclosporine A, tacrolimus, and sirolimus in whole blood as well as mycophenolic acid in plasma using common pretreatment procedure.

The purpose of the study was to develop rapid and simple procedure for simultaneous determination of cyclosporine A (CsA), tacrolimus (TCR), and sirolimus (SIR) in whole blood and mycophenolic acid (MPA) in plasma. Ascomycin (ASCO), cyclosporine D (CsD), and desmethoxysirolimus (DMSIR) were used as internal standards (IS) for TCR, CsA and MPA, and SIR, respectively. In the method development, six-level blood calibrators were used for CsA (range 47-1725 ng/ml), TCR (range 2.