超声微波协同萃取-双波长分光光度法测定食品中亚硝酸盐含量

Determination of Nitrite Content in Food by Dual Wavelength Spectrophotometry after Ultrasonic and Microwave Assisted Extraction

研究了超声微波协同萃取法提取食品中亚硝酸盐的最佳提取条件,并用双波长分光光度法测定亚硝酸盐的含量。结果表明：超声微波协同萃取最佳工艺参数为在pH 7.5、料液比1∶10、提取功率50W条件下提取6min;与传统水浴提取法比较,提取率增加了3.02%～14.60%。双波长分光光度法测定条件：pH值在4～9范围内,硝酸盐和亚硝酸盐测定波长分别为202,209nm,线性范围分别为0.04～0.2,0.02～0.2μg/mL。应用于食品样品测定,相对标准偏差为1.57%～4.56%,加标回收率为95.6%～107.5%,其测定结果与国标盐酸萘乙二胺显色法比较,相对误差在0.11%～6.5%。

The aim is to study the optimum extraction conditions of nitrite in food by ultrasonic- microwave assisted extraction, and the nitrite content of samples is determined by using dual wavelength spectrophotometry. The optimal conditions for extraction of nitrite are pH 7. 5 for 6 min with an microwave power of 50 W and a solid-to-liquid ratio of 1 ： 10 （g/mL）, the extraction rate is 3.02% - 14. 60% higher than that by Chinese national GB standard method. The determination conditions for dual wavelength spectrophotometry are as follows, pH 4-9, the wavelengths are 202, 209 nm respectively for nitrate and nitrite determination. The absorbance has good linear relationship with nitrate and nitrite content of 0. 04-0. 2, 0. 02-0. 2 μg/mL. The adding standard recovery rate ranges from 95.6% to 107.5% and the relative standard deviation is between 1.57% and 4.56%. Additionally, the relative errors are in 0. 11%-6. 5% compared with hydrochloric acid naphthalene ethylenediamine chromogenie method.