Simultaneous analysis of 31 anti-impotence compounds potentially illegally added to herbal-based dietary supplements by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

In this paper, an ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF HRMS) method was developed and validated for screening, confirmation and quantitation of 31 anti-impotence compounds potentially illegally added to herbal-based dietary supplements. The analytes were well separated by the mobile phase consisted of 0.1% formic acid solution and acetonitrile with gradient elution at a flow rate of 0.3 mL/min. The MS analysis was operated in positive mode and the mass error of the 31 compounds were below 2.9 ppm. The method validation showed good linearity with coefficients of determination (r) higher than 0.9973 for all analytes. LODs and LLOQs ranged from 0.005 to 0.50 μg/g or μg /mL and from 0.02 to 1.24 μg /g or μg/mL, respectively. The accuracy was in the range of 86.6% to 113.7%, while the intra-and inter-day precision were in the ranges of 0.9-7.6% and 0.9-11.4%, respectively. The absolute and relative matrix effect were in the range of 65.8-115.6% and 0.6-13.3%. The mean recoveries were in the range of 80.5-116.9%. The stability ranged from 0.4% to 8.5%. Among 200 batches of herbal-based dietary supplements, sildenafil and/or tadalafil were found to be added illegally in two samples, while not very high concentration of icariin was detected in one sample. The Q-TOF mass spectrometry has been proved to be a very powerful and efficient tool for rapid screening of 31 anti-impotence compounds potentially illegally added to herbal-based dietary supplements, ensuring food safety and public health.