Study on the fingerprint profile of Monascus products with HPLC–FD, PAD and MS

Monascus products have been widely used as food additives and pharmaceuticals. Citrinin is a toxic metabolite produced during the Monascus fermentation. In this work, a quick extraction method with ultrasonic treatment was studied for a complete extraction of citrinin from the fungi cells. Furthermore, the proposed HPLC method has the advantage of the simultaneous determination of Monascus pigments and citrinin without sample pretreatment. Under the optimized HPLC conditions, a baseline resolution of pigments, citrinin and other catabolites was achieved. The detection limit of citrinin reached 0.5 ng mL−1 (S/N > 3/1) with a fluorescence detector (FD). Eight Monascus pigments were detected, with photodiode array detector (PAD), two of which not yet described. The HPLC fingerprint profile of the eight Monascus pigments and citrinin appears significant for the quality control of the Monascus product.