Fully automated method based on on-line molecularly imprinted polymer solid-phase extraction for determination of lovastatin in dietary supplements containing red yeast rice
Abstrakt
A fully automated method for the determination of lovastatin in dietary supplements containing red yeast rice has been developed. It uses a sequential injection analysis system combined with solid-phase extraction applying highly selective molecularly imprinted polymer sorbent.
A miniaturized column for on-line extraction was prepared by packing 4.5mg of the sorbent in a 5.0x2.5-mm-i.d. cartridge, which was used in the flow manifold. Sequential injection analysis manifold enabled all steps of lovastatin extraction and continuous spectrophotometric detection at 240nm.
A limit of detection of 60 mu g g(-1), a limit of quantitation of 200 mu g g(-1), and a linear calibration range of 200-2000 mu g g(-1) were achieved. Intra-day and inter-day precision values (RSD) were <=6.7% and <=4.9%, respectively, and method recovery values of spiked red yeast rice extracts at 200, 1000, and 2000 mu g g(-1) concentration levels were 82.9, 95.2, and 87.7%.
Our method was used for determination of lovastatin lactone in four dietary supplements containing red yeast rice as a natural source of lovastatin, also known as monacolin K. The extracted samples were subsequently analyzed by the reference UHPLC-MS/MS method.
Statistical comparison of results (F test, t test, alpha=0.05) obtained by both methods did not reveal significant difference. A substantial advantage of the new automated approach is high sample throughput thanks to the analysis time of 7.5min, miniaturization via down-scaling the extraction column, and smaller sample and solvent consumption, as well as reduced generation of waste.