Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) for the enantiomeric analysis of D,L-selenomethionine in food supplements and urine.
Capillary gas chromatography inductively coupled plasma mass spectrometry (CGC-ICPMS) was applied to the determination of D- and L-selenomethionine in food supplements and in urine. Derivatization was performed with ethylchloroformate (ECF) offering the advantage that the reaction can be carried out in aqueous medium i.e. urine. The derivatives were separated on the chiral stationary phase (CSP) Chiralsil-L-Val. The method was validated with D- and L-seleno-ethionine as internal standard (IS) and the linearity for a seven point calibration from 12.5 pg to 2.5 ng per enantiomer was excellent (R(2) 0.9997). Repeatability of injection (n=3) was <1.8%. The limit of detection (LOD) and quantification (LOQ) were 4 and 12 pg, respectively. Food supplements presently on the market contain L-selenomethionine for at least 90%. Repeatability of the whole procedure (n=6) was tested on one L-selenomethionine formulation and was 3.8 (R.S.D.%). Data for urine samples after a daily intake of L-selenomethionine or the racemate D,L-selenomethionine corresponding to 100 microg selenium indicate that the D-enantiomer is not metabolized.
Devos
Christophe
C
Department of Organic Chemistry, Ghent University, Krijgslaan 281 S4, B-9000 Ghent, Belgium.
Sandra
Koen
K
Sandra
Pat
P
D019587:Dietary Supplements / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D012645:Selenomethionine / Q000652:urine*; D013237:Stereoisomerism
D012645:Selenomethionine