调味酱油中苯甲酸钠的检测研究

Detection of Sodium Benzoate in Seasoned Soy Sauce

采用紫外可见分光光度法(Ultraviolet visible spectrophotometry,UVS)对酱油中防腐剂苯甲酸钠进行测定,考察了实验体系的显色时间、酸碱性(pH值)及干扰因素对防腐剂苯甲酸钠紫外可见吸收光谱的影响。在最优实验条件下,于波长223.5 nm处绘制防腐剂苯甲酸钠的标准曲线,R2=0.99928,其线性范围为10~40μg/m L,方法检出限为0.2μg/m L,相对标准偏差为2.70%。采用乙醚-磷酸氢二钠萃取体系对调味酱油样品1、样品2、样品3进行前处理,同时利用紫外可见分光光度法对上述样品进行检测分析。结果表明:样品1、2、3中苯甲酸钠的含量分别为0.5665 g/kg、0.6448 g/kg、0 g/kg,均低于国家标准中苯甲酸钠1.18 g/kg的含量要求。乙醚-磷酸氢二钠体系的调味酱油样品前处理方法具有操作简单、用时少、萃取率高等优点。紫外可见分光光度法对于酱油中防腐剂苯甲酸钠的测定有快速、高效、准确等特点。

The ultraviolet visible spectrophotometry(UVS)was used to research the preservative sodium benzoate in soy sauce,the effects of coloration time,acidity and alkalinity(pH)of the system,interference factors on the UV-visible absorption spectrum of the sodium benzoate were investigated.Under the optimal experimental conditions,the standard curve of the sodium benzoate was plotted at 223.5 nm with R2=0.99928,the linear range of 10–40μg/mL,the method detection limit was 0.2μg/mL,and the relative standard deviation was 2.70%.The pretreatment of soy sauce samples 1,2 and 3 was carried out using the ether-disodium hydrogen phosphate extraction system,and the above samples were also analyzed by UVS.The results showed that the content of sodium benzoate in sample 1,2,3 was 0.5665,0.6448 g/kg and 0 g/kg respectively.These values were lower than the national standard content of sodium benzoate 1.18 g/kg.The pre-treatment method for seasoning soy sauce samples using the ether disodium hydrogen phosphate system has the advantages of simple operation,low time consumption,and high extraction rate.The UVS has the characteristics of fast,efficient,and accurate determination of sodium benzoate,a preservative in soy sauce.