Desenvolvimento de métodos analíticos para a avaliação da qualidade de cafés torrados, bebidas energéticas e medicamentos contendo esteroides anabolizantes utilizando a espectroscopia de RMN 1H
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Data
2018-04-20
Autores
Ribeiro, Marcos Vinícius de Moura
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A espectroscopia de Ressonância Magnética Nuclear (RMN) é uma técnica analítica sofisticada e poderosa com uma variedade de aplicações em diferentes campos da pesquisa científica, principalmente na área farmacêutica e alimentícia. Tornou-se nos últimos anos uma das mais potentes e versáteis técnicas para a análise qualitativa e quantitativa tanto para os produtos naturais quanto para as misturas complexas. A autenticidade de alimentos e medicamentos tem sido uma preocupação constante em todo o mundo devido, principalmente, os potenciais riscos à saúde dos consumidores e danos econômicos significativos causados por fraudes e adulterações. O objetivo principal deste trabalho foi avaliar a autenticidade de cafés torrados, bebidas energéticas e medicamentos contendo esteroides anabolizantes, utilizando a RMN. As medidas espectroscópicas em RMN 1H foram realizadas em um espectrômetro de 600 MHz. Para as análises de cafés torrados, os métodos desenvolvidos, permitiram a discriminação (origem geográfica e adulteração) de cada tipo de café analisado, além de apontar as principais diferenças em suas composições. Os modelos quimiométricos de análise de componentes principais (PCA) e análise discriminante (DA), foram utilizadas para a diferenciação das amostras analisadas. A rapidez com que os resultados puderam ser obtidos e a não exigência de um pré-tratamento da amostra, evitando alterações na composição da mesma, tornou essa ferramenta (RMN aliada a quimiometria), muito atrativa, apresentando resultados concordantes com os obtidos por metodologia oficial (microscopia óptica). Já para o estudo da autenticade de esteroides anabolizante, foram avaliadas 52 amostras de diversos princípios ativos. Do total de amostras analisadas, 80% apresentou algum tipo de adulteração (incluindo a presença ou ausência de substâncias não declaradas no rótulo e percentual de ingrediente ativo abaixo do informado na embalagem). Todas os métodos desenvolvidos foram validados de acordo com os parâmetros da ANVISA, e apresentaram limites de detecção (LD) e quantificação (LQ) variando entre 0,18-0,62 e 0,98-2,35 mg mL-1, respectivamente. Nos ensaios de precisão, o desvio padrão relativo (DPR) intra-dia variou de 1,56 a 4,22% e o DPR inter-dia de 2,19 a 4,73%. Os valores de recuperação variaram de 95,2% a 104,0%. Para as medidas quantitativa foram avaliadas a determinação em RMNq via padrão interno (dimetil sulfona) e por calibração externa (via Electronic Reference to access in vivo Concentrations - ERECTIC 2). A comparação dos resultados obtidos pelo método desenvolvido com os métodos de referência (Cromatografia Líquida de Alta Eficiência - CLAE), demonstram que ambos foram estatisticamente concordantes. Por fim, para as análises de bebidas enérgicas, a técnica de RMN foi utilizada para a quantificação simultânea de cafeína e taurina, a fim de verificar, se os níveis no produto final estavam de acordo com os limites legais e com o teor apresentado no rótulo do produto. Das 15 amostras analisadas, 6 apresentaram uma quantidade de taurina inferior a declarada no rótulo do produto, enquanto que para cafeína 5 amostras apresentaram quantidade inferior à declarada na embalagem, estando em desacordo com a legislação brasileira. Os métodos desenvolvidos para determinação de cafeína e taurina foram validados apresentando excelentes resultados e posteriormente foram comparados a métodos disponíveis na literatura.
Nuclear Magnetic Resonance (NMR) spectroscopy is a sophisticated and powerful analytical technique with a variety of applications in different fields of scientific research, mainly in the pharmaceutical and food sciences. It has become in recent years one of the most powerful and versatile techniques for qualitative and quantitative analysis for both natural products and complex mixtures. The authenticity of food and medicines has been a worldwide concern, mainly due to the potential health risks to consumers and significant economic damage caused by fraud and adulteration. The authenticity of food and medicines has been a worldwide concern, mainly due to the potential health risks to consumers and significant economic damage caused by fraud and adulteration. The main objective of this work was to evaluate the authenticity of roasted coffees, energy drinks and drugs containing anabolic steroids, using the NMR. The 1H NMR spectroscopic measurements were performed using a 600 MHz spectrometer. For the analysis of roasted coffee, the methods developed allowed the discrimination (geographical origin and adulteration) of each type of coffee analyzed, besides pointing out the main differences in their compositions. The principal component analysis (PCA) and discriminant analysis (DA) models were used to differentiate the analyzed samples. The rapidity with which the results could be obtained and the non-requirement of a pre-treatment of the sample, avoiding changes in the composition of the sample, made this tool (NMR with chemometrics) very attractive, presenting results consistent with those obtained by official methodology (optical microscopy). For the study of anabolic steroid authentication, 52 samples of several active principles were evaluated. Of the total samples analyzed, 80% showed some kind of adulteration (including the presence or absence of undeclared substances on the label and percentage of active ingredient below that reported on the package). All the methods developed were validated according to ANVISA parameters, and showed limits of detection (LOD) and quantification (LOQ) ranging from 0.18-0.62 to 0.98-2.35 mg mL-1, respectively. In the precision assays, the intra-day relative standard deviation (RSD) ranged from 1.56 to 4.22% and the inter-day RSD from 2.19 to 4.73%. Recovery values ranged from 95.2% to 104.0%. For the quantitative measurements the determination of the qNMR in the internal standard (dimethyl sulfone) and external calibration (by Electronic Reference to access in vivo Concentrations - ERECTIC 2). The comparison of the results obtained by the method developed with the reference methods (High Performance Liquid Chromatography - HPLC), show that both were statistically concordant. Finally, for the analysis of energetic drinks, NMR technique was used for the simultaneous quantification of caffeine and taurine in order to verify if the levels in the final product were in compliance with the legal limits and with the content presented on the label of product. Of the 15 samples analyzed, 6 presented a lower amount of taurine than the one declared on the product label, while for caffeine 5 samples presented less than the declared amount on the packaging, being in disagreement with the Brazilian legislation. The methods developed for determination of caffeine and taurine were validated with excellent results and later compared to methods available in the literature.
Nuclear Magnetic Resonance (NMR) spectroscopy is a sophisticated and powerful analytical technique with a variety of applications in different fields of scientific research, mainly in the pharmaceutical and food sciences. It has become in recent years one of the most powerful and versatile techniques for qualitative and quantitative analysis for both natural products and complex mixtures. The authenticity of food and medicines has been a worldwide concern, mainly due to the potential health risks to consumers and significant economic damage caused by fraud and adulteration. The authenticity of food and medicines has been a worldwide concern, mainly due to the potential health risks to consumers and significant economic damage caused by fraud and adulteration. The main objective of this work was to evaluate the authenticity of roasted coffees, energy drinks and drugs containing anabolic steroids, using the NMR. The 1H NMR spectroscopic measurements were performed using a 600 MHz spectrometer. For the analysis of roasted coffee, the methods developed allowed the discrimination (geographical origin and adulteration) of each type of coffee analyzed, besides pointing out the main differences in their compositions. The principal component analysis (PCA) and discriminant analysis (DA) models were used to differentiate the analyzed samples. The rapidity with which the results could be obtained and the non-requirement of a pre-treatment of the sample, avoiding changes in the composition of the sample, made this tool (NMR with chemometrics) very attractive, presenting results consistent with those obtained by official methodology (optical microscopy). For the study of anabolic steroid authentication, 52 samples of several active principles were evaluated. Of the total samples analyzed, 80% showed some kind of adulteration (including the presence or absence of undeclared substances on the label and percentage of active ingredient below that reported on the package). All the methods developed were validated according to ANVISA parameters, and showed limits of detection (LOD) and quantification (LOQ) ranging from 0.18-0.62 to 0.98-2.35 mg mL-1, respectively. In the precision assays, the intra-day relative standard deviation (RSD) ranged from 1.56 to 4.22% and the inter-day RSD from 2.19 to 4.73%. Recovery values ranged from 95.2% to 104.0%. For the quantitative measurements the determination of the qNMR in the internal standard (dimethyl sulfone) and external calibration (by Electronic Reference to access in vivo Concentrations - ERECTIC 2). The comparison of the results obtained by the method developed with the reference methods (High Performance Liquid Chromatography - HPLC), show that both were statistically concordant. Finally, for the analysis of energetic drinks, NMR technique was used for the simultaneous quantification of caffeine and taurine in order to verify if the levels in the final product were in compliance with the legal limits and with the content presented on the label of product. Of the 15 samples analyzed, 6 presented a lower amount of taurine than the one declared on the product label, while for caffeine 5 samples presented less than the declared amount on the packaging, being in disagreement with the Brazilian legislation. The methods developed for determination of caffeine and taurine were validated with excellent results and later compared to methods available in the literature.
Descrição
Palavras-chave
RMN 1H, Autenticidade, Validação, Café, Esteroides anabolizantes, Bebidas energéticas, 1H NMR, Authenticity, Validation, Coffee, Anabolic steroids, Energy drinks