Analysis of weight-loss compounds in health supplements by ultrasonic extraction, dispersive sorbent cleanup, and liquid chromatography tandem mass spectrometry quantification.

Current society is facing the global surge in obesity rates, making people more aware of the importance of body weight control and increasing the consumption of weight-loss supplements due to their over-the-counter status. However, certain producers have intentionally adulterated supplements with prescription weight-loss drugs without label declaration, necessitating suitable analytical methods for routine analysis of illegal weight-loss compounds in health supplements. In this study, a rapid, effective, and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of 11 wt-loss compounds in three supplement forms (i.e., hard capsule, soft capsule, and tea powder). A suitable analytical procedure was selected via the optimization of LC-MS/MS parameters and sample preparation conditions. The samples were ultrasonicated with methanol, and the extracts were cleaned up using dispersive solid-phase extraction with C18 and carbon sorbent. The method was validated for specificity, linearity, method detection and quantification limits, precision, and accuracy, producing good satisfaction. The method was applied to analyze 82 health supplement samples collected from the Vietnamese market, in which seven samples were found to be adulterated with at least one of the target compounds. Sibutramine, phenolphthalein, and benzylsibutramine were detected in 7/82, 5/82, and 2/82 samples with concentration ranges of 0.44-16.4, 0.54-2.14, and 0.14-1.43 mg/g, respectively. These results indicated the method applicability to the quality control of health supplements in developed and emerging countries.