Automated analysis for vitamin E in butter by coupling sample treatment continuous membrane extraction liquid chromatography with electrochemical detection
Mmd. Zamarreno et al., Automated analysis for vitamin E in butter by coupling sample treatment continuous membrane extraction liquid chromatography with electrochemical detection, ANALYT CHIM, 386(1-2), 1999, pp. 99-106
An automated procedure for the determination of vitamin E in samples of but
ter with minimum sample manipulation has been developed. Following dissolut
ion of the samples in a micellar medium (methanol-Triton X-100-water), on-l
ine sample treatment involving alkaline hydrolysis is coupled with a separa
tion and enrichment system in a cell containing a silicone membrane; the an
alyte-rich phase is finally connected to a liquid chromatographic analytica
l system - using a Cl8 column with electrochemical detection controlling th
e whole system automatically. The proposed procedure has been successfully
applied to the determination of vitamin E in samples of butter, using 2,2,5
,7,8-pentamethyl-6-chromanol as internal standard. The coefficient of varia
tion obtained was 6.7% for a inter-day assay. (C) 1999 Elsevier Science B.V
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