Desenvolvimento e validação de metodologia para a determinação de nitrito em carnes processadas por espectroscopia molecular após solubilização alcalina da amostra

Abstract

In this work a new methodology was developed for the determination of nitrite in processed meat by molecular absorption spectrometry UV-VIS, and the sample preparation was performed by alkaline solubilization with tetramethylammonium hydroxide (TMAH). The solubilization procedures with TMAH are well known in atomic spectrometric techniques and becoming increasingly popular, with numerous applications in the determination of macro and micro constituents in several biological samples. Thus, the main objective of this work was to verify if this procedure to prepare biological samples could be extended to the techniques of molecular spectroscopy for the determination of nitrite in processed meat. The solution resulting from the solubilization of 500 mg of dry sample showed a concentration of 0.45% m/v TMAH for a final volume of 50 mL. The procedure developed showed a calibration range from 0.1 to 2.0 mg L-1 NO2 - , with R2 = 0.999, LD = 0.013 mg L-1 and recoveries were in the order of 92 at 107 %. The results showed that the solubilization of the samples of bologna, sausage and pate with TMAH also is effective for the spectrophotometric determination of nitrite by UV-VIS. The proposed method showed some advantages compared to other known methods, especially highlighting the possibility of a single step sample preparation be possible to use simultaneously in atomic and molecular techniques. Additionally, the methodology showed accuracy, precision, speed, simplicity and low cost, with less waste generation, contributing with the green chemistry and also have the necessary parameters to be used in routine analyzes. Certainly the procedure can be extended to other biological samples, as well as new applications in molecular techniques.