基于^(1)H-NMR的饮料中苯甲酸钠定量分析

Quantitative Analysis of Sodium Benzoate in Beverages Based on^(1)H-NMR

建立一种基于核磁共振氢谱(^(1)H Nuclear Magnetic Resonance,^(1)H-NMR)快速测定饮料及口服液中苯甲酸钠含量的方法。采用noesygpprld核磁脉冲序列压制水峰,以吡嗪为内标,采集待测样品氢谱;对比内标物和苯甲酸钠定量峰的响应峰面积,计算出样品中苯甲酸钠的浓度。建立苯甲酸钠积分值和浓度的标准曲线Y=4.2633X+0.0035,苯甲酸钠质量浓度在0.015~2 g/L范围内线性关系良好,相关系数(r)为0.9999,检出限为1.03×10^(−2)g/L,定量限为3.11×10^(−2)g/L。样品平行测试6次的相对标准偏差为0.77%,该方法精密度良好;采用3个不同浓度加标,加标回收率在98.06%~99.93%之间。利用建立的方法测定19种饮料及口服液中苯甲酸钠含量,与高效液相色谱方法进行比对,相对偏差小于5%,证明^(1)H-NMR方法的可行性和准确性。试验建立的核磁共振氢谱法操作简单,可快速准确测定饮料及口服液中苯甲酸钠含量。该方法可为生产企业及监管部门提供参考。

A^(1)H-NMR method was developed for the quantification of sodium benzoate in beverages and oral liquids.The hydrogen spectra of the samples were collected by using noesygpprld nuclear magnetic pulse sequence to suppress the water peak,and using pyrazine as the internal standard.Compare the response peak area of the internal standard and sodium benzoate quantitative peak to calculate the concentration of sodium benzoate in the samples.The plot of the peak area integral value versus concentration of sodium benzoate couold be used to obtain the linear regression equation Y=4.2473X+0.0035,and the correlation coefficient(r)was calculated to be 0.9999 in the range of 0.015-2 g/L,which indicated that this method had good linearity.The SLOD and SLOQ values were determined to be 1.03×10^(−2)g/L and 3.11×10^(−2)g/L,respectively.The relative standard deviation of 6 parallel determinations was 0.77%,and the recoveries of the three concentrations were 98.06%-99.93%.The content of sodium benzoate in 19 kinds of beverages and oral liquids was determined by the established method.The relative deviation between the results obtained by the^(1)H-NMR and the high-performance liquid chromatography was less than 5%,which proved the feasibility and accuracy of this method.The^(1)H-NMR method established was simple to operate,and could determine the content of sodium benzoate quickly and accurately in beverages and oral liquid.This method could provide a reference for production enterprises and regulatory authorities.