Determination of Illegal Adulterant in Herbal Medicines and Dietary Supplements by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Abstract

Adulterations with synthetic drugs are common problems with herbal medicines and this can potentially cause serious adverse effects. In this paper, a robust LC-MS/MS method for the sensitive and reliable determination of 33 illegal adulterations from herbal medicines and dietary supplements was established. The drugs were isolated from herbal sample using 70% (v/v) methanol. Chromatographic separation was done using C18 column (150x4.6 mm id., 5 µM) with gradient elution of 0.1% (v/v) formic acid and methanol at flow rate of 0.6 ml/min. For most drugs, two transitions were monitored (multiple reaction monitoring; MRM) using protonated or deprotonated as precursor ions under their respective optimal collision energy for each compound. The detection limit was in the level of picogram and the separation of at least 30 compounds can be done in 30 min. The application of this method was used in the sample of herbal medicines, dietary food supplements, coffee for weight controlling and cola drink, totally 49 samples. The adulterate found was dexamethasone in a sample of herbal medicines used for muscle ache, sibutramine was found in 2 samples of dietary food supplements and caffeine was found in 3 samples of dietary food supplements that did not claim on product. With this developed method for analysis of adulterants in herbal medicine, the product quality can be better controlled and regulated to ensure consumers’ safety.