Automatic determination of coenzyme Q10 in food using cresyl violet encapsulated into magnetoliposomes

A new type of magnetoliposomes (MLs), containing hydrophobic magnetic-gold nanoparticles and the long wavelength fluorophore cresyl violet, has been used for the determination of coenzyme Q10 (CoQ10). MLs were concentrated just before the detector, using a flow system and an external electromagnet device. The subsequent introduction of Triton X-100 and CoQ10 causes the MLs lysis and the cresyl violet oxidation, obtaining a decrease in the fluorescence signal. The dynamic range of the calibration graph was 0.03-0.50μmolL^-1 CoQ10, and the detection limit was 0.008μmolL^-1. The precision (relative standard deviation) was in the range of 1.3-4.5%. The method showed a sampling frequency of 12h^-1 and was applied to the determination of CoQ10 in several food samples. The results were compared with those obtained using a previously described chromatographic method. Also, recovery values were in the range of 83.5-101.3%.