p-Anisidine value: Evaluation of p-anisidine hydrochloride as an alternative reagent to p-anisidine

Abstract: Thermal decomposition of hydroperoxides during frying generates several secondary oxidation products, with carbonyl compounds predominating. p‐Anisidine value (p‐AV) is the most prominent official method for quantifying these carbonyl compounds, utilizing the reaction between carbonyls, principally 2‐alkenals and 2,4‐dienals, and p‐anisidine (para‐methoxy aniline) reagent. Although the toxicity of the p-anisidine reagent is not in question, there is no supporting data for its carcinogenicity in human. Regardless, the carcinogenic risk remains a major concern in laboratories where there is potential for prolonged exposures, subjecting its usage to specific regulatory requirements in some regions. In the current study, we have evaluated, for the first time, p-anisidine hydrochloride as an alternative reagent, considering that its usage in the analytical and quality assurance laboratories is relatively less prohibitive, presumably from its more favorable Environmental Health and Safety (EHS) hazard rating. Results from this study reveal a significant differences in relative sensitivity of p-anisidine and its salt to 2-alkenals and 2,4-dienals, potentially providing a significant opportunity for diagnostic research in lipid oxidation mechanisms. An excellent correlation (R² > 99.8%) was observed between anisidine value unit obtained with both reagents, with an appropriate modification of the p-anisidine hydrochloride reagent.