Validation of a Quick and Effective Method for Determining Nitrate and Nitrite in Meat Products / Validação De Método Rápido E Eficaz Para Determinação De Nitrato E Nitrito Em Produtos Cárneos

Abstract

In order to implement quick and low residues assays, reflectometry methods for nitrate and nitrite quantification in meat products were validated. Measurement uncertainties were estimated and the methods were applied in commercial samples. The established work range for nitrate determination was 0.007 to 0.188 g/100g expressed in NaNO2. Limits of detection and quantification were 0.0042 and 0.0067 g/100g, respectively. Recovery results were between 90 and 115%, and the precision between 4.1 and 12.8%. The method revealed itself selective in the presence of interferers, except for nitrites, what made necessary its previous elimination. The relative expanded uncertainty varied between 5.3 e 14.2%. The method's repeatability was the greatest source of contribution for the uncertainty. The established work range for nitrite determination was 0.0056 to 0.028g/100g expressed in NaNO2. Limits of detection and quantification were 0.0009 and 0.0056 g/100g. Recovery results were between 81 and 85%, and precision between 4.4 and 10.8%. Phosphates (0.5 g/100g) and ascorbic acid (0.01 g/100g) were evaluated as interferes. Expanded relative uncertainty varied between 2.9 and 4.9%. The methods turned out simple, quick and suitable for the analyte's quantification. Applying the methods in commercial samples, satisfactory results according to maximum limits established by the law were obtained.