Desenvolvimento e validação de métodos cromatográficos para a determinação dos produtos de oxidação do glicerol

Abstract

Biodiesel is one of the most promising renewable fuels, as can be obtained from renewable energy sources. This production mainly occurs through a transesterification reaction producing biodiesel and glycerol. An alternative to the use of glycerol is via a catalytic oxidation reaction processes and using catalysts which can generate a range of products with different applications ranging from the pharmaceutical industry to petrochemical industries. In this work two analytical methods were developed, one based on liquid chromatography (HPLC) and a gas chromatography (GC) for the identification, separation and quantification of these products. During the development of methods were used 8 analytical standards. The HPLC method was validated by checking parameters such as selectivity, linearity, precision, repeatability, intermediate precision, instrumental precision, accuracy, robustness, limit of detection and quantification limit. These parameters were evaluated taking into account both the area and the height of the peaks. The analytical curves showed a correlation coefficient ≥0,9978. The proposed method was sensitive and need for concentration range adopted 1.3 to 55 mg L-1. The instrumental precision, intermediate precision and repeatability were obtained CV values ≤ 9.3%. The method accuracy showed recovery values 89-108% in both the real sample and the matrix fortified by the standards. The proposed method is robust to small temperature variations (± 5 °C). In the method developed by gas chromatography it was necessary to perform a pretreatment of the samples in order to make thermally stable analytes for analysis in GC. This pretreatment was carried out by a derivatization reaction. two were tested derivatizing, BSTFA - N, O-Bis (trimethylsilyl) trifluoroacetamide MSTFA - N-methyl-N- (trimethylsilyl) trifluoroacetamide) being chosen BSTFA which responded positively to all analytes of interest in about 15 minutes of reaction. In the chromatographic method developed by GC it took 20 minutes of analysis, thus totaling a methodology with a total time of 35 minutes.