MSACL 

1. Comparison of TSQ Vantage, Exactive and LTQ Velos for Quantitative Analysis of 1,25 Dihydroxyvitamin D in Plasma
Mon 12:00 PM - PosterSplash Track 1
Barbora Chindarkarova
Thermo Scientific
Barbora Chindarkarova, Oksana Gvozdyak, Julie Horner, Marta Kozak

Thermo Scientific
Introduction
1,25-Dihydroxyvitamin D is the active metabolite of vitamin D produced by kidney. The plasma concentration in healthy person ranges from 6 - 60 pg/mL. Poor ionization efficiency and extensive fragmentation in MS/MS results in inadequate MRM sensitivity. All reported methods use extensive and irreproducible sample preparation including derivatization. We are investigating quantitative plasma assay and here we present the performance on standards using three MS platforms: TSQ VantageTM triple quadrupole MS, VelosTM dual linear ion trap MS, and ExactiveTM ultra-high resolution MS.

Method
1,25-Dihydroxyvitamin D standards in 50% MeOH were analyzed with 2 minutes gradient on HypersilTM aQ GOLD column. The same LC method and the same APCI source parameters were used on the three mass spectrometry platforms to obtain LOQ and linearity range.
Four SRM transitions on Vantage, water lost fragment in MS/MS spectrum on LTQ Velos, and full scan MS at 100,000 resolution on Exactive were used for quantitation.

Preliminary Data
The Vantage triple quadrupole in MRM mode has a LOQ of 100 pg/mL. Both Exactive and LTQ Velos generated an LOQ of 50 pg mL. At 50 pg/mL, the Exactive S/N is about 5 times higher than Velos. Linearity range on both Exactive and LTQ Velos is 50-10 000 pg/mL.
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