加速氧化甲基兰测定食品中微量亚硝酸盐含量

Accelerated Oxidation of Methyl Blue for Determination of Trace Nitrite in Foods

利用亚硝基在酸性条件下,可以促进溴酸钾对甲基兰的氧化,使甲基兰褪色,建立微量亚硝酸含量测定方法。反应体系在550nm波长处有最大吸收峰,在亚硝酸浓度0.2～1.2μg/ml范围内呈线性相关(r为0.994),平均回收率为93.16%。香肠、红肠、硝猪肉、硝牛肉和硝排骨中亚硝酸盐含量分别为(15.27±0.08)、(44.15±0.13)、(90.57±1.69)、(99.83±2.75)和(52.13±1.10)mg/kg;大白菜随着贮藏时间延长,亚硝酸盐含量逐渐增加,腐败时跃迁到6.97mg/kg。

Nitrite can accelerate the oxidation reaction of methyl blue with potassium bromate in acidic medium, which causes the color fading of methyl blue. Based on it, a detection method for the trace nitrite in food was developed in the present study. The maximum absorption peak of the reaction system was presented at 550 nm, and in the nitrite concentration of 0.2-- 1.2μg/ml there was a good linear correlation （r = 0.994）. The average spike recovery in meat products was 93.16%. The nitrite contents in Chinese sausage, red sausage, nitrite pork, nitrite beef and nitrite pork chop were （15.27 ±0.08）, （4.15±0.13）, （90.57 ± 1.69）, （99.83± 2.75） and （52.13 ±1.10） mg/kg, respectively. The nitrite content in Chinese cabbage increased with the prolongation of storage time, and reached 6.97 mg/kg when the decay of Chinese cabbage happened.