酸碱滴定法测定食品中二氧化硫的条件优化

Optimization of Conditions for Determination of Sulfur Dioxide in Food by Acid-base Titration

目的优化实验条件,建立稳定的测定食品中二氧化硫的酸碱滴定法。方法以腐竹中二氧化硫的质控样作为样品,通过改变充氮蒸馏法的加热条件和氮气流速进行多次实验,用过氧化氢溶液吸收蒸馏物,根据氢氧化钠标准溶液消耗量计算二氧化硫含量得到不同结果,将其结果与质控样指定值比较,确立充氮蒸馏法的最优条件。再用优化条件进行方法验证。结果充氮蒸馏法的加热功率保持在150 W,氮气流速在0.2 mL/min时,二氧化硫测定结果最佳。本方法的相对标准偏差(RSD%)为2.8%~3.9%、回收率范围在95.2%~98.1%、检出限为1 mg/kg、定量限为10 mg/kg。方法稳定、操作简单,适合在基层检验机构推广。

Objective:Optimize the experimental conditions and establish a stable acid-base titration method for the determination of sulfur dioxide in food.Methods:With the quality control sample of sulfur dioxide in Rolls of dried bean milk creams as the sample,several experiments were carried out by changing the heating conditions and nitrogen flow rate of the nitrogen filled distillation method.The distillate was absorbed by hydrogen peroxide solution,and the sulfur dioxide content was calculated according to the consumption of sodium hydroxide standard solution,and different results were obtained.The results were compared with the specified values,and the optimal conditions of the nitrogen filled distillation method were established.Then use this condition to verify the method.Results:When the distillate boils,quickly adjust the heating power to 150 W and keep the nitrogen flow rate at 0.2mL/min,the best result is obtained.The relative standard deviation(RSD%)is 2.8%~3.9%,the recovery range is 95.2%~98.1%,the detection limit is 1 mg/kg,and the quantitative limit is 10mg/kg.