干制红枣中天然苯甲酸的测定及本底分析

The determination of natural benzoic acid in dried red dates and background analysis

采用高效液相色谱法、二极管阵列检测器,建立了定性和定量测定红枣中苯甲酸的检测方法,分析测定红枣中苯甲酸的含量范围分布。样品通过水溶液超声振荡提取,高效液相色谱柱分离测定,在红枣中分离鉴定出一种天然有机酸成分——苯甲酸。样品经处理后,使用三种不同品牌的色谱柱,在相同的色谱条件下,均呈现出与苯甲酸标准品相同的保留时间和紫外吸收光谱图,证实了红枣中天然苯甲酸的存在。本方法的线性范围为1.0~100.0mg/L,线性关系好,R为0.999,方法的定量限为0.010g/kg,在0.010g/kg、0.050g/kg和0.100g/kg三个添加水平下的回收率均大于85%。该方法可为其他植物中天然有机酸化学成分的定性、定量测定提供参考。本文还通过对全国三个主产区共122批干制红枣样品进行检测,初步明确了其中天然苯甲酸的本底值范围,为制订或修订食品行业相关标准提供了重要依据。

Using high performance liquid chromatography and diode array detector, a detection method was developed for the qualitative and quantitative determination of benzoic acid in red jujube, which can analytically determine the range distribution of benzoic acid content in red jujube. After extracted by aqueous solution, a natural component （benzoic acid） was isolated from red jujube by HPLC. After treatment, the sample showed same retention time and ultraviolet absorption spectrum using three different C 18 chromatogram columns under same chromatographic conditions, which approved the existence of natural benzoic acid in red jujube. This method showed a good linear relationship in the range of 1.0 - 100.0mg/L with R=0.999, the limit of quantity （LOQ） was 0.010g/kg, recovery rates were all greater than 85% at addition levels of 0.010 g/kg, 0.050 g/kg and 0.100g/kg respectively. This method could provide reference for the qualitative and quantitative determination of chemical composition in other natural organic acids. This article also initially determined the scope of background values of natural benzoic acid of 122 batches of dried jujube samples from the three main producing regions, which provided important evidence for establishing and amending related standards in food industry.