Introduction
Automated sample preparation using the Biotage® Extrahera™ was compared to an equivalent manual method utilizing a vacuum manifold. Analytes were extracted from pooled stripped plasma using a supported liquid extraction procedure. ISOLUTE® SLE+ 400 μL sample volume plates, part number 820-0400-P01 were used for extraction.
Resulting extracts from both sample preparation methods were subsequently analyzed by LC-MS/MS.

Procedure
A pooled plasma sample was prepared in a sufficient quantity to run a full 96-well plate for each processing method. This pooled plasma sample was fortified with 25-OH Vitamin D2 and D3 at a concentration of 30 ng/mL respectively. 25-OH Vitamin D3-d6 was added as an internal standard at a concentration of 30 ng/mL.From this pooled plasma sample 200 μL was transferred to all wells of two 96-well plates. All subsequent aspects of sample preparation were performed in duplicate on two separate plates utilizing either Extrahera or manual preparation using a calibrated air-displacement pipette.
