Quantification of Nitrite in Dairy Products Employing a Novel UV-Sensitizer Technique
摘要
Nitrite in dairy products can be converted into highly carcinogenic nitrosamines and cause acute poisoning, making its detection critically important for preventing health risks and ensuring food safety compliance. This study established a UV spectrophotometric method based on the sensitization effect of Tween-60 for highly sensitive detection of nitrite ions (NO2−) in liquid milk. Using potassium iodide as a reducing agent in a strongly acidic medium, nitrite ions react with iodide ions to form iodine. The introduction of Tween-60, a nonionic surfactant, as a sensitizer significantly enhances the characteristic absorption peak intensity of the system at 290 nm and 360 nm in the ultraviolet region. Through systematic optimization of reaction conditions, 290 nm was determined as the optimal detection wavelength. A linear relationship was demonstrated between the absorbance difference (ΔA) and NO₂⁻ concentration within the range of 3.2 × 10−4 to 2.5 × 10−3 mmol/L (linear equation: ΔA = 538.93c—0.17, R2 = 0.9964). The method achieved a detection limit (LOD) of 5.57 × 10−5 mmol/L, with precision and accuracy meeting quantitative analysis requirements. Compared with traditional methods, the Tween-60 sensitization system substantially improves detection sensitivity while offering low reagent costs and operational simplicity, providing a reliable theoretical foundation and technical pathway for developing portable rapid nitrite detection kits.