Desenvolvimento de métodos analíticos para determinação de metais em tintas anti-incrustantes

Abstract

In this work, it presents a study involving the use of a new sample preparation method for Al determinations, Ba, Cu, Fe, Li, Mg, Mn, Pb, Sn and Zn in antifouling paints by techniques atomic spectrometry as F AAS and MIP OES. Furthermore, it investigated the capability of the analysis of the antifouling paints by the LIBS technique, which optimization studies were performed scanning and developing a method for the quantitative determination of macroelements. The acid decomposition under reflux system was compared with the calcination procedure based on ASTM standard method with sample mass modification. The conditions for acid decomposition were optimized and performed using 5 mL of HNO3 at a heating temperature of the digester block at 220 ° C for 3 h. The sample preparation time was significantly reduced when compared with the calcination method. The limits of quantification in mg g-1 for the acid decomposition method were 0.09; 0.99 and 0.015 for Cu, Fe and Zn by F AAS, and 0.003; 0.001; 0.030; 0.045; 0.004; 0.016, 0.011; 0.602; 0.120 and 0.044 for Al, Ba, Cu, Fe, Li, Mg, Mn, Pb, Sn and Zn by MIP OES, respectively. The accuracy of the sample preparation method was performed by recovery test and the results varied between 84 and 120% for all analytes in the samples of antifouling paints. Three anti-fouling paints obtained in the local market were analyzed and showed low levels of concentration for the investigated analytes, except for Fe, Cu and Zn, and Cu concentrations were relatively higher, element this used to replace Sn in antifouling paints. The acid decomposition with reflux system proved to be quick, practical, with simplicity and enhanced security when compared to the standard method. Furthermore, LIBS technique has enabled the development of a method for determination of Fe, Cu and Zn, based on serial dilutions of paints with organic solvent and construction of calibration curves based on analytical concentrations defined by F AAS. The results were satisfactory, with only the proviso that the method has a limitation for the determination of low concentrations of Fe.