Analysis of Pharmacologic Adulteration in Dietary Supplements by Capillary Zone Electrophoresis Using Simultaneous Contactless Conductivity and UV Detection

The consumption of dietary supplements is increasing every year all over the world. In addition, the consumption has been accompanied by the increased frequency of adulteration of the products with synthetic pharmaceuticals. Analytical methods that allow testing the presence of synthetic drugs in dietary supplements are needed to detect such fraudulent practices. This paper describes the study of furosemide, hydrochlorothiazide, chlorthalidone and amiloride (diuretics), fluoxetine and paroxetine (antidepressants), and phenolphthalein (laxative) and amfepramone (anorexic) in dietary supplements marketed in Brazil for weight loss and physical fitness claims. A total of 113 products were acquired from websites and physical stores. The analytical method applied in this work involved the separation of the compounds by capillary zone electrophoresis in a working electrolyte consisting of 30% (v/v) methanol in a 20-mmol L-1 phosphate buffer (pH 9.2) and capacitively coupled contactless conductivity detection and UV detection simultaneously. The method was validated in accordance with the appropriate guideline of the Association of Analytical Communities (AOAC) and was successfully applied to the analysis of the samples of dietary supplements. Hydrochlorothiazide was present in 14 of the studied samples. One sample presented furosemide in addition to hydrochlorothiazide, both acting as diuretics.