Simultaneous analysis of six polymethoxyflavones and six 5-hydroxy-polymethoxyflavones by high performance liquid chromatography combined with linear ion trap mass spectrometry.

Polymethoxyflavones (PMFs) and monohydroxylated polymethoxyflavones (OH-PMFs) exist exclusively in the citrus genus, particularly in citrus peels. Currently, due to the broad application of PMFs and OH-PMFs in nutraceuticals, pharmaceuticals, and functional foods, their identification and quantification will be of great significance and the first criteria to meet. We have developed a validated method with high performance liquid chromatography coupled with linear ion trap mass spectrometry. The method was fully validated in linearity, precision, accuracy, and recovery. Six PMFs and their monohydroxyl counterparts, six 5-OH-PMFs, were simultaneous analyzed within 20 min for the first time. The LOD (limit of detection) and LOQ (limit of quantitation) were calculated as 0.02-0.23 and 0.05-0.76 μg/mL, respectively. The method was performed on the samples of acid treated citrus peel extracts. The citrus peel extracts with high content of PMFs and 5-OH PMFs may provide reliable and economical resources in biological activity studies and development of health beneficial products.