离子色谱法和分光光度法测定茶叶中的铅铬绿含量

Determination of lead chrome green in tea by ion chromatography and spectrophotometry

中文关键词:  铅铬绿  铬酸根  离子色谱法  铁蓝  分光光度法  茶叶

英文关键词:lead chrome green  chromate  ion chromatography  iron blue  spectrophotometry  tea

中文摘要:

      目的 建立离子色谱法和分光光度法测定茶叶中的铅铬绿含量的方法。方法 分别测定茶叶中的铅和铬酸根, 得到样品中铬酸铅的含量, 当铬酸铅有检出时, 通过测定茶叶中的铁蓝进一步明确茶叶中的染色为铅铬绿所致。铅的测定采用GB 5009.12《食品安全国家标准 食品中铅的测定》, 铬酸根的测定采用离子色谱法, 铁蓝的测定采用分光光度法。结果 本方法采用离子色谱法和分光光度法, 间接测定铅铬绿的主要成分铬酸铅和铁蓝, 实现了茶叶中无机绿色颜料的定量测定。此方法中铬酸铅的检出限为30 mg/kg, 铁蓝的检出限为3 mg/kg。结论 该方法客观、准确、灵敏, 适合茶叶中铅铬绿的测定。

英文摘要:

      Objective To establish a method for determination of lead chrome green in tea by ion chromatography and spectrophotometry. Methods The lead and chromate in the tea were separately measured to obtain the lead chromate content in the sample. When the lead chromate was detected, it was further determined that the dyeing in the tea leaves was lead chrome green by measuring iron blue in the tea leaves. Lead was determined by GB 5009.12 National standard for food safety-Method for determination of lead in foods. Chromate was detected by ion chromatography. And iron blue was detected by spectrophotometry. Results The lead chromate and iron blue (the main components of lead chrome green) was indirectly determined by ion chromatography and spectrophotometry, realizing the quantitative determination of inorganic green pigment in tea. The limit of detection of lead chromate and iron blue was 30 mg/kg and 3 mg/kg, respectively. Conclusion This method is objective, accurate and sensitive, which is suitable for the determination of lead chrome green in tea.