摘要
建立离子色谱法测定绿茶中亚硝酸盐和硝酸盐的含量的方法,茶样前处理方式模拟日常饮茶方式制备茶叶浸提液,依次经过C18柱、Ag柱和Na柱净化,直接进样,采用KOH梯度洗脱。亚硝酸盐和硝酸盐工作曲线呈良好的线性相关,相关系数分别为0.9999和0.9992;添加三个浓度水平的加标回收率在96.3%~106.0%之间,精密度测试的相对标准偏差(RSD)值均小于5%。采用该方法对市售46个茶叶进行亚硝酸盐和硝酸盐的检测,结果显示各地所采集的绿茶中亚硝酸盐均存在未检出的情况,检出率和检出含量低。但几乎所有的样品中硝酸盐均检出,且有27.8%茶叶样品硝酸盐含量逼近甚至超过250 mg/kg。
An ion chromatography method was established to determine the content of nitrite and nitrate in green tea.In the pretreatment of tea samples,tea extracts were prepared by simulating the way of daily tea drinking.After purification on C18 column,Ag column and Na column,samples were directly injected and then eluted by KOH gradient.There was a good linear correlation between nitrite and nitrate working curves,and the correlation coefficient was 0.9999 and 0.9992,respectively.The recovery rates of the three concentrations ranged from 96.3%to 106.0%,and the relative standard deviations(RSD)of the precision tests were all lower than 5%.The method was used to detect the nitrite and nitrate in 46 tea leaves sold in the market.The results showed that the nitrite in green tea collected from different places had not been detected,and the detection rate and detection content were low.However,almost all nitrates were detected,and the nitrate content in 27.8%of the samples approached or even exceeded 250 mg/kg.
作者
许洋
王智
孙羽婕
田伟
冯德建
周黎黎
XU Yang;WANG Zhi;SUN Yujie;TIAN Wei;FENG Dejian;ZHOU Lili(Standard and Testing Technology of Tea Key Laboratory of Sichuan Province,National Institute of Mearsurement and Testing Technology,Chengdu 610021,China)
出处
《中国测试》
CAS
北大核心
2021年第12期58-63,共6页
China Measurement & Test
基金
四川省应用基础研究项目(2019YJ0625)
四川省重点研发项目(2020YFN0003)。
作者简介
许洋(1988-),男,四川绵阳市人,助理研究员,研究方向为茶学;通讯作者:周黎黎(1981-),女,四川达州市人,副研究员,硕士,研究方向为食品科学。
