Evaluation of a modified extraction approach for nitrite determination in cured meats: effects of matrix, pH, and analytical conditions

Abstract Nitrite plays a critical role in the safety and quality of cured meat products; however, accurate quantification of residual nitrite is essential for regulatory compliance. Conventional spectrophotometric methods based on filtration are widely used but may be susceptible to matrix-related interference in complex meat systems. This study evaluated a modified extraction approach incorporating zinc sulphate (ZnSO₄) and sodium tetraborate (borax) to improve nitrite determination. The method was assessed across aqueous standards, reagent systems, and pepperoni matrices under varying conditions of dilution, pH, temporal stability, and nitrate presence. Analytical performance was evaluated using linearity, recovery, precision, and multifactorial statistical analysis. The adapted method demonstrated strong linearity, high recovery, and reduced variability compared to the conventional method, particularly in complex matrices and at higher concentrations. However, it showed sensitivity to pH, with reduced performance under neutralised conditions. Systematic differences between methods indicated matrix-related effects in the conventional approach, while the adapted method provided more consistent quantification under controlled conditions. These findings highlight the importance of extraction methodology in nitrite analysis and support improved accuracy in food safety and regulatory monitoring.