Desenvolvimento de um procedimento analítico para a determinação espectrofluorimétrica de nitrato e nitrito em leite explorando um composto de coordenação à base de európio (III)

Abstract

Milk is a very important food for humans, being a great source of proteins and minerals essential for maintenance of life. Due to this fact, public and private policies emphasize the need to produce quality products. The milk goes through several management processes, from milking until arrive at supermarket’s shelves, which are fundamental for its quality maintenance. Usually investments are made in air-conditioned facilities, reservoirs and equipment made of antioxidant material and training of those involved in the production process. However, these points do not show an obvious profitable end for entrepreneurs in dairy industry. Based on this fact, some companies resort to more practical methods, such as addition of adulterants in milk, so that it is conserved. The fundamental point of using these additives is inhibition of microbial proliferation. Sodium and potassium nitrites and nitrates are on the list of preservatives widely used by the food industry. The use of these two anions in food is related to their preservative power, however, its excess in a body can cause problems due to their toxicity, causing an endogenous formation of nitrosamines that have potentials carcinogenic, teratogenic and mutagenic potentials. The objective of this work is to develop a methodology that aims to determine nitrate and nitrite in milk samples consumed by population of Recife in Pernambuco’s state, through interaction of these anions with a coordination compound [Eu(12-crown-4).2phen].Cl3, responsible for system's fluorescence, since the interaction with nitrate and nitrite partially suppresses its fluorescence in this way, enabling the linear correlation between the concentration of the analytes and quenching of the coordinating compound. Those analytical answers were obtained by using with concentration from 0.5 to 10.0 mg.L-1, obtained a correlation coefficient readings were performed varying the concentration between 0.5 to 10.0 mg.L-1 {RNO3 = 0.9941 / RNO2 = 0.995}, demonstrating the feasibility of the proposed method for analysis of nitrate and nitrite.