Determinação de compostos sulfurados em amostras de asfalto de petróleo empregando cromatografia líquida de alta eficiência com detecção por arranjo de fotodiodos

Abstract

The presence of organosulfur compounds in petroleum-derived asphalts is related to several negative characteristics, such as catalyst poisoning and corrosion of equipment during the refining process, as well the acceleration of aging processes, reducing the useful life of this material in the asphalt pavement, leading to a great economic impact, since the asphalt oil cement is the most widely used material in the world for this purpose. In addition, recent studies have shown that sulfur compounds are emitted in asphalt fumes, which can be a major environmental pollutant, and cause intoxication to the workers during application, because it is at this stage that fumes are emitted in greater quantity, and it is well known the great carcinogenic and mutagenic potential that these molecules possess. In this context, the development of a methodology for the determination of organosulfur compounds in asphalt matrices was done using the analytical technique high performance liquid chromatography with diode array detector (HPLC - DAD). A group of organosulfur compounds that are present in petroleum derivatives were chosen and could be used as pollution markers in environmental analyzes, geological markers and possible aging agents. The method was validated, allowing the separation and detection of 16 analytes, with low detection limits. Different approaches to sample preparation were studied in view of the high complexity of the matrix. The cleaning with solid phase extraction (SPE) cartridges carried out in asphalt fractions obtained by the Green and Payzant fractionation methodologies. With the use of the extraction and collection device (DEC) it was possible to identify and quantify the compound tianaftene in the form of volatiles, in the concentration of 7.62 mg kg-1. The obtained results showed that the DEC is more appropriate for the study of this matrix, and that new studies using different cleaning methodologies must be done in order to obtain the analytes free in the matrix.