Avaliação de diferentes técnicas de preparo de amostras para determinação de bixina e metformina em plasma de rato por UHPLC-DAD-MS/MS

Abstract

In this work, two methods, one for bixin, by liquid-liquid extraction, another one for metformin, by protein precipitation, both extracted from samples of rat plasma, were developed and validated. Due to the complexity of the plasma composition, it was necessary to use sample preparation techniques to eliminate interferents and/or preconcentrate. The liquid-liquid extraction was used to extract bixin with subsequent analysis by ultra-high performance liquid chromatography associated to an absorbance with photodiode array detector and subsequent sequential mass spectrometry (UHPLC-DAD-MS/MS). Protein precipitation was employed in the extraction of metformin, which was analyzed by ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS). The methods developed for bixin and for metformin were validated and accuracy values were obtained per recovery experiment near 103 and 102%, respectively. The precision obtained, in terms of coefficient of variation, was 10% for both compounds. The quantification limit was 40 ng mL-1 for bixin and 1 ng mL-1 for metformin with a coefficient of variation of 15 and 13%, respectively. The linear range of work was 200- 2200 ng mL-1 for bixin and 5-500 ng mL-1 for metformin. The results obtained are consistent with the literature, allowing the extraction and subsequent analysis of the compounds from a complex matrix, in the rat blood plasma. In addition, the sample volumes used in the liquid-liquid extraction of bixin are lower than those found in the literature.