双波长分光光度法同时测定食品中硝酸盐、亚硝酸盐方法研究.rar

摘要:本课题采用双波长分光光度法测定食品中的亚硝酸盐与硝酸盐的方法而展开的研究。以蒸馏水为参比溶液，配制5µg/mL硝酸钠标准溶液和8µg/mL亚硝酸钠标准溶液测定其峰值分别为202nm，209nm。通过光照、加热时间、添加剂、温度、pH值等不同的单因素条件实验和正交实验确定加热时间、pH值、加热温度对本实验的影响。结果表明，在pH值为7.00，加热时间为10min，加热温度为70℃时为最佳条件。用超声波-微波协同萃取仪提取样品中的硝酸盐和亚硝酸盐，用双波长分光光度法在最佳条件下对样品测定，方法检出限为3.695ng/L，硝酸钠相对标准偏差为1.15%～3.62%，加标回收率在100.29%～102.36%之间。其测定结果与国标测定结果相比较，相对误差在0.01%～0.05%之间；亚硝酸钠相对标准偏差为1.57%～4.56%，加标回收率在102.96%～106.12%之间，其测定结果与国标测定结果相比较，相对误差在0.11%～6.5%之间。

　　　此方法简便快捷，无污染，抗干扰能力强，可作为一种快速检测亚硝酸盐和硝酸盐的方法。

关键词  硝酸钠、亚硝酸钠、双波长分光光度法、国标法

Abstract:This topic adopts dual-wavelength spectrophotometry method was developed for the determination of nitrite and nitrate in foods by research.With distilled water as the reference solution,sodium nitrate standard determination of the peak is at 209 nm , sodium nitrite standard determination of the peak is at 202 nm.Through light,heating time,additive temperature,pH value, different conditions of single factor experiment and orthogonal experiment is to determine heating time, the influence of pH value, heating temperature. The results show that the best of the pH value is 7.00, the best of the heating time is 10 min,  the heating temperature is 70 as the best conditions.Use ultrasonic - synergistic extraction apparatus of microwave extraction of nitrate and nitrite in the samples,with double wavelength spectrophotometry determination under the optimum condition of sample, the method detection limited is 3.695 ng/L. The relative standard deviation of nitrite in 1.15%～3.62%, the standard addition recovery of nitrite in 100.29%～102.36%, its determination result compared with national standard determination results, the relative error is in 0.01%～0.05%; relative standard deviation of nitrite in 1.57%～4.56%, the standard addition recovery of nitrite in 102.96%～106.12%.Its determination result compared with national standard determination results, the relative error is in 0.11%～6.5%. 

　　　This method is convenient, no pollution, strong anti-interference ability, can be used as a rapid detection method of nitrite and nitrate.

Keywords  sodium nitrate  sodium nitrite  dual wavelength spectrophotometry  national standard method