Avaliação de sorvente MIP em sistema de microextração hifenado ao HPLC-DAD, para determinação de taninos condensados em amostras de casca de jabuticaba (Myrciaria cauliflora)

• Autor(a) principal: Cardoso, Alessandra Timóteo
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/11969
• topic: Jabuticaba; Métodos de extração online; Catequina; MIP; HPLC-DAD; Online extraction methods; Catechin; HPLC-DAD; CIENCIAS EXATAS E DA TERRA::QUIMICA

Jabuticaba (Myrciaria cauliflora) is a fruit widely consumed in Brazil and of great nutritional importance. Among the compounds of this fruit are the condensed tannins, which have already been widely investigated regarding their chemical, biological and pharmaceutical properties, which makes the extraction and isolation of these compounds of great economic and environmental importance. According to the literature, the extraction of tannins from jabuticaba for isolation in separation techniques has been carried out by conventional methods such as solid phase extraction (SPE). However, these techniques have a limited selectivity, in addition, a high volume of solventes is necessary, which consequently generates a large amount of waste. Thus, it is necessary to research more selective and ecologically correct methods. Thus, the present work proposed the development and optimization of an online extraction method based on molecularly imprinted polymers (MIP) used in a capillary column for the isolation and identification of condensed tannins in jabuticaba peel. Therefore, catechin was used as a template molecule for MIP and non-imprinted polymer (NIP) was synthesized for comparison studies. The sorbent characterization was performed using scanning electron microscopy (SEM), nitrogen desorption and adsorption analysis, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), thermogravimetry (TG) and diffraction X-ray (XRD). The data obtained with the characterization of the phase showed similarity with the literature, regarding to the possibility of applying these materials as an extractor phase in liquid chromatography with diode array detector(HPLC-DAD). When evaluating the applicability of the column filled with the molecularly printed polymer in HPLC-DAD, it was noted that it presented good results for the extraction of catechin, especially when compared to the non-imprinted polymer. The results of the method optimization indicated that the mobile phase flow of 20 µL min-1 and injection volume of 40 µL were the best in terms of asymmetry and peak resolution, in addition to maintaining the extraction efficiency, decreasing the generation of organic residues. On the other hand, the figures of merit evaluated showed greater selectivity in the MIP in relation to the NIP for catechin, coefficients of variation from 2.6 to 7.3% between extractions, indicating excellent reproducibility of the columns and preconcentration factor of the MIP phase of 5.14%. Regarding the reuse capacity of the columns, a value of relative standard deviation of 3.83% was found, indicating that the columns can be used more than 40 times without losing the extraction efficiency, which is consistent with the result obtained for the memory effect, in which the solvent chromatogram showed no peaks at the same retention time for catechin. The quantification of tannins condensed in the matrix using the vanillin method by the UV-vis spectrum at 500 nm, indicated a content of 59.1 µg mL-1 of the compounds present in jabuticaba's aqueous extracts based on the standard curve of catechin constructed in the concentrations of 0.01 to 1 mg mL-1, which showed relevance in terms of the choice of this matrix. Furthermore, the analyzes performed by HPLC-DAD for the real samples showed efficiency of the MIP column for catechin extraction, eliminating the interferents and concentrating the analyte.