Direct Analysis in Real Time (DART) Mass Spectrometry of Adulterants in Herbal Slimming Products using a Tandem Quadrupole MS and Data Directed Analysis

Several troubling studies show the adulteration of herbal slimming products with sibutramine is a common occurrence. Recent reports suggesting an increased risk of serious cardiovascular events (such as heart attack or stroke) in patients with known cardiovascular disease taking sibutramine have prompted the European Medicines Agency (EMA) to recommend that the use of sibutramine be suspended. The aim of this study is to develop specific methods for the rapid screening of herbal medicines for illicit adulteration with pharmaceutical drugs.

Herbal slimming aids were purchased over the internet from store websites and auction sites. Samples were analysed using a direct analysis in real time (DART) interface and a tandem quadrupole mass spectrometer. Samples purchased over the internet were found to contain undeclared pharmaceutical substances with the main component being sibutramine, an appetite suppressant used in the treatment of obesity. In addition to sibutramine, phenolphthalein and sildenafil were also identified none of which were declared on the box or enclosed information.

During our study we were able to identify nine samples that had been contaminated by sibutramine. DART with data directed analysis of the sample using a data directed high low collision energy experiment provides simultaneous intact molecular ion and fragmentation information, while allowing samples to be analysed very rapidly and without the need for complex sample preparation or chromatography. The testing of unlicensed herbal medicines and herbal dietary supplements are vital functions due to the possibility of illegal adulteration and/or contamination and the potential that exists for adverse health effects to unsuspecting consumers.