DESENVOLVIMENTO DE METODOLOGIA ANALÍTICA PARA DETERMINAÇÃO DE SIBUTRAMINA EM SUPLEMENTOS ALIMENTARES ATRAVÉS DE CROMATOGRAFIA GASOSA ACOPLADA A ESPECTROMETRIA DE MASSAS

Abstract

This work presents the validation and application of a GC-MS analytical method for determination of sibutramine in food supplements. Initially, a study was conducted to optimize the extraction procedure of sibutramine from food supplements. For this, addition standard and recovery experiments were performed. The effect of the extractor solvent (methanol or acetonitrile), type of homogenization source (ultrasson or microwave) and number of homogenization cycles (three or five) in the sibutramine recovery was investigated by factorial design 2³. To verify the suitability of the developed analytical method, the parameters selectivity, linearity, precision and accuracy were investigated by different statistical tools. Under the analytical conditions employed, Sibutramine had a retention time of 7.43 min and showed a narrow chromatographic peak slightly tail. Comparison of the chromatograms and mass spectra for the peak in 7.43 min for the standard, the reference supplement and the spiked supplement, as well as, for the samples studied indicate that the method is selective. The high selectivity of the method is guaranteed by combining chromatographic data retention time and the spectroscopic data. Additionally, all quantitative analyses were performed in the selective ion monitoring mode (SIM), where only the ion m/z 114.1 (quantifier) and the qualifiers ions m/z 72.1 and 137 were monitored by the mass spectrometer. The results indicated that the proposed method provides good accuracy and precision with appropriate recovery rates between 80-115% and RSD for repeatability and intermediate precision of 4.26 and 9.40%, respectively. The limits of detection (LOD) and quantification (LOQ) were 14.94 and 45.29 ng.mL-1, respectively, demonstrating the ability of the method to determine sibutramine in low concentrations. The method showed good linearity in the range of concentrations (50-1100 ng·mL-1) with a determination coefficient of 99.09% and showed no indication of lack of fit Ffaj = 1.01 (p> 0.05). Thus, the study demonstrated that the proposed analytical methodology can be considered validated for the determination of sibutramine in food supplements. To check possible tampering with sibutramine of weight-loss dietary supplements, the validated method was applied in nine samples from different manufacturers. However, sibutramine was not detected in any sample. Additionally, an analysis of the chemical composition of dietary supplements was performed to assess the agreement of the chemical composition described in the product label with the actual composition. The presence of caffeine and steroid Acetate androst-5-en-3-ol-7,17-dione (DHEA), not declared on the label of some products was observed, which can cause serious risks to the health of consumer. Our study indicates the need for a more rigorous quality control to ensure the safety of consumption of dietary supplements.