Polímero de impressão molecular sintetizado por micro-ondas para extração em fase sólida e quantificação de cocaína em amostras ambientais

Abstract

Cocaine is an illicit drug of abuse that causes numerous social problems and the measurement of its consumption by the population requires more precise methodologies for quantification in different environmental samples and one of the ways is the quantification of the metabolites or original molecules in the sewage network. The solid phase extraction (SPE) technique using molecular imprinting polymer (MIP) as solid phase (MISPE) is a technique that allows to eliminate the interferences from the matrix and concentrate the sample. Therefore, MIPs were synthesized using microwave energy (MW) in different parameters for use in MISPE. The polymers were produced in powers of 80W and 100W and in the range of 15 to 60 minutes of reaction time. After the synthesis, the mass yield, molecular structure, thermal stability and surface area were analyzed. Then, two polymers synthesized with the cocaine as template molecule (MIP-1C and MIP-10C) were compared and finally the MIP-10C was used to quantify cocaine in urban sewage in the city of Poços de Caldas (MG). The results obtained showed a mass yield of more than 90% for the addition of Cocaine as a target molecule when compared to the polymer without addition of a template molecule and an increase in mass yield of 39% for adjustments only in the synthesis potency. In all analyzed polymers, the incorporation of the cross-linker into the polymer structure and the alteration of the chemical structure with the addition of the template molecule was demonstrated by the FTIR technique. The thermal stability was determined up to 120 ºC and when increasing the synthesis power to 100W, the polymer was synthesized after 15 minutes and at 80W there was a 65% increase in the surface area (BET) when compared to the power of 100W. The best synthesis results were obtained at 80W of power and 30 minutes of reaction time. The MIP adsorption and desorption tests showed an adsorption capacity of cocaine from the aqueous medium of 1.37% of the polymer weight, a recovery rate of 90% and the analysis of urban sewage estimated a monthly population consumption in Poços de Caldas (MG) of approximately 1,113 kg of powder containing cocaine.