Details

Autor(en) / Beteiligte

• Fazili, Zia
• Whitehead, Ralph D.
• Paladugula, Neelima
• Pfeiffer, Christine M.

Titel

A high-throughput LC-MS/MS method suitable for population biomonitoring measures five serum folate vitamers and one oxidation product

Ist Teil von

• Analytical and bioanalytical chemistry, 2013-05, Vol.405 (13), p.4549-4560

Ort / Verlag

Berlin/Heidelberg: Springer-Verlag

Erscheinungsjahr

2013

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Small specimen volume and high sample throughput are key features needed for routine methods used for population biomonitoring. We modified our routine eight-probe solid phase extraction (SPE) LC-MS/MS method for the measurement of five folate vitamers [5-methyltetrahydrofolate (5-methylTHF), folic acid (FA), plus three minor forms: THF, 5-formylTHF, 5,10-methenylTHF] and one oxidation product of 5-methylTHF (MeFox) to require less serum volume (150 μL instead of 275 μL) by using 96-well SPE plates with 50 mg instead of 100 mg phenyl sorbent and to provide faster throughput by using a 96-probe SPE system. Total imprecision (10 days, two replicates/day) for three serum quality control pools was 2.8–3.6 % for 5-methylTHF (19.5–51.1 nmol/L), 6.6–8.7 % for FA (0.72–11.4 nmol/L), and ≤11.4 % for the minor folate forms (<1–5 nmol/L). The mean (±SE) recoveries of folates spiked into serum (3 days, four levels, two replicates/level) were: 5-methylTHF, 99.4 ± 3.6 %; FA, 100 ± 1.8 %; minor folates, 91.7–108 %. SPE extraction efficiencies were ≥85 %, except for THF (78 %). Limits of detection were ≤0.3 nmol/L. The new method correlated well with our routine method [ n  = 150, r  = 0.99 for 5-methylTHF, FA, and total folate (tFOL, sum of folate forms)] and produced slightly higher tFOL (5.6 %) and 5-methylTHF (7.3 %) concentrations, likely due to the faster 96-probe SPE process (1 vs. 5 h), resulting in improved SPE efficiency and recovery compared to the eight-probe SPE method. With this improved LC-MS/MS method, 96 samples can be processed in ∼2 h, and all relevant folate forms can be accurately measured using a small serum volume. Figure High-throughput LC-MS/MS method for population monitoring of serum folate forms