US EPA

1173472 

Journal Article 

Automated analysis of vitamin E isomers in vegetable oils by continuous membrane extraction and liquid chromatography-electrochemical detection 

Sanchez-Perez, A; Delgado-Zamarreno, MM; Bustamante-Rangel, M; Hernandez-Mendez, J 

2000 

Yes 

Journal of Chromatography A
ISSN: 0021-9673
EISSN: 1873-3778 

ELSEVIER SCIENCE BV 

AMSTERDAM 

881 

1-2 

229-241 

English 

10905706 

10.1016/s0021-9673(00)00314-9 

WOS:000087787000018 

A rapid and automated method for the analysis of alpha-, gamma- and delta-tocopherols in vegetable oils is reported. Continuous extraction of vitamin E isomers from oil samples dissolved in Triton X-114 in the presence of methanol-hexane is achieved and coupled on-line with the chromatographic system. Using an acetic acid/sodium acetate buffer in a methanol-water (97:3) solution as the mobile phase, a C18 stationary phase and electrochemical detection in the coulometric mode, alpha-, gamma- and delta-tocopherol isomers can be successfully analyzed within 17 min. Thirteen commercially available oils of olive, sunflower, corn and seed mixtures were analyzed using 2,2,5,7,8-pentamethyl-6-chromanol as internal standard. The results obtained using three methodologies, one of them including classical sample treatment for liposoluble vitamin analysis, were in good agreement. To validate the proposed method, analysis of the only BCR Reference Material available, with a certified content of alpha-tocopherol (margarine CRM 122), was carried out using the automated methodology, the results found being in agreement with the certified value. 

automation; vegetable oils; extraction methods; food analysis; vitamins; tocopherols