Simultaneous determination of oxidized and reduced coenzyme Q and alpha-tocopherol in biological samples by high performance liquid chromatography with platinum catalyst reduction and electrochemical detection.
A convenient and sensitive high performance liquid chromatographic method with post-column platinum catalyst reduction and electrochemical detection was applied to the simultaneous determination of oxidized and reduced coenzyme Q (CoQ and CoQH2) and alpha-tocopherol (alpha-TP) in human and rat samples. After the separation of oxidized and reduced CoQ homologues (CoQ8-CoQ10 and CoQ8H2-CoQ10H2) and alpha-TP on a reversed-phase column, oxidized CoQ homologues were reduced on a platinum catalyst reduction column, and then all the reduced forms were quantified with an electrochemical detector operated in the oxidation mode (+ 0.6 V vs. Ag/AgCl). The order of elution was alpha-TP, CoQ8H2, CoQ9H2, CoQ8, CoQ10H2, CoQ9, and CoQ10 and all were well separated within 13 min. The detection limits at a signal-to-noise ratio of 3 were 20 pg for alpha-TP, 70 pg for CoQ8 and CoQ8H2, and 100 pg for CoQ9, CoQ9H2, CoQ10 and CoQ10H2. Quantitative recoveries (93-102%) from serum and tissues were obtained for all the analytes studied. This method was applied satisfactorily to the simultaneous determination of CoQ, CoQH2 and alpha-TP in biological materials.
Wakabayashi
H
H
Department of Analytical Chemistry, Niigata College of Pharmacy, Japan.
Yamato
S
S
Nakajima
M
M
Shimada
K
K
D000328:Adult; D000375:Aging / Q000378:metabolism; D000818:Animals; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D004566:Electrodes; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D010984:Platinum; D051381:Rats; D017208:Rats, Wistar; D014451:Ubiquinone / Q000032:analysis* / Q000097:blood; D014810:Vitamin E / Q000032:analysis* / Q000097:blood
D014451:Ubiquinone; D014810:Vitamin E; D010984:Platinum