Simultaneous analysis of 4 specific antihypertensive adulterants in herbal products using LC-MS/MS

A sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous analysis of 4 compounds used for treating hypertension as adulterants in herbal products. The method was validated in terms of selectivity, linearity, accuracy, limit of detection (LOD), limit of quantitation (LOQ), and precision in accordance with AOAC and ICH guidelines. The LOD and LOQ of all compounds were about 0.3 ng/mL and 1 ng/mL, respectively. The linearity was good (R2 > 0.999), with intra-day and inter-day precision levels not more than 9.85% and 8.51%, respectively, and 81.9 – 109.8% accuracies. Thirty commercial herbal products consisting of traditional medicines and dietary supplements available in Vietnamese markets were tested. While none contained detectable amounts of the 4 antihypertensive compounds, the developed LC-MS/MS procedure can be used for routine analysis to monitor illegal adulteration in various forms of herbal products.