title: Assay of coenzyme Q(10) in plasma by a single dilution step.
abstract: A new method is described for determining coenzyme Q(10) (CoQ(10)) in plasma. The method is based on oxidation of CoQ(10) in the sample by treating it with para-benzoquinone followed by extraction with 1-propanol and direct injection into the HPLC apparatus. This method achieves a linear detector response for peak area measurements over the concentration range of 0.05-3.47 microM. Diode array analysis of the peak was consistent with CoQ(10) spectrum. Supplementation of the samples with known amounts of CoQ(10) yielded a quantitative recovery of 96-98.5%; the method showed a level of quantitation of 1.23 nmol per HPLC injection (200 microl of propanol extract containing 33.3 microl of plasma). A correlation of r = 0.99 (P < 0.0001) was found with a reference electrochemical detection method. Within run precision showed a CV% of 1.6 for samples approaching normal values (1.02 microM). Day-to-day precision was also close to 2%.
authors.affiliation: Institute of Biochemistry, Institute of Biomedical Sciences, Faculty of Medicine, University of Ancona, Via Ranieri, 60131 Ancona, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Mosca
authors.forename: Daniele
authors.initials: D
authors.lastname: Fattorini
authors.forename: Stefano
authors.initials: S
authors.lastname: Bompadre
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Littarru
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D002138:Calibration; D002498:Centrifugation; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003067:Coenzymes; D004563:Electrochemistry / Q000379:methods; D004795:Enzyme Stability; D006801:Humans; D007201:Indicator Dilution Techniques; D016014:Linear Models; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D016227:Benzoquinones; D003067:Coenzymes; D014451:Ubiquinone; C004532:quinone; C024989:coenzyme Q10