混合基体改进剂-石墨炉原子吸收光谱法测定 速溶茶中的铅镉铬

Detection of lead, cadmium and chromium in instant tea by mixed matrix modifier-graphite furnace atomic absorption spectrometry

中文关键词:  基体改进剂  石墨炉原子吸收  速溶茶  铅  镉  铬

英文关键词:matrix modifier  graphite furnace atomic absorption  instant tea  lead  cadmium  chromium

中文摘要:

      目的 以微波消解为前处理方式, 建立一种石墨炉原子吸收光谱法测定速溶茶中微量重金属铅、铬、镉的实验方法。方法 采用高压密闭微波消解仪对速溶茶进行消解, 加入硝酸铵、硝酸钯等基体改进剂消除样品干扰, 并优化仪器条件进行石墨炉原子法测定。结果 测定速溶茶中铅、铬、镉的最佳基体改进剂分别为硝酸铵-硝酸钯混合基体改进剂、硝酸钯基体改进剂、硝酸铵-硝酸钯混合基体改进剂。在最佳实验条件下, 铅、铬、镉的线性范围分别为0~80 μg/L、0~40 μg/L、0~2 μg/L, 检出限分别为0.3681 μg/L、0.1268 μg/L、0.0076 μg/L, 铅、镉、铬的标准曲线相关系数分别为0.9990、0.9978和0.9992, 回收率均在98.64%~101.9%之间, 样品测定相对标准偏差均小于5%。结论 该方法简便、快速、准确, 可作为速溶茶中铅、镉、铬快捷、可靠的检测方法。

英文摘要:

      Objective To establish a method for the determination of heavy metal lead, chromium and cadmium in instant tea by graphite furnace atomic absorption spectrometry (GFAAS) with microwave digestion. Methods Solid instant tea powder was slaked in high pressure sealed microwave digestion instrument, with adding ammonium nitrate, nitric acid matrix modifier for eliminating the sample disturbance. Instrument conditions were optimized for graphite furnace atomic spectrometry. Results The optimal matrix modifiers for the determination of lead, chromium, cadmium in instant tea were ammonium nitrate and palladium nitrate mixed matrix modifier, palladium nitrate as matrix modifier, ammonium nitrate and palladium nitrate mixed matrix modifier, respectively. Under the optimum experimental conditions, the linear ranges of lead, chromium and cadmium were 0~80 μg/L, 0~40 μg/L, and 0~2 μg/L and their detection limits were 0.3681 μg/L, 0.1268 μg/L, and 0.0076 μg/L. The correlation coefficients of lead, cadmium and chromium standard curve were 0.9990, 0.9978 and 0.9992, respectively. The recoveries rate were between 98.64%~101.9% and the relative standard deviation was less than 5%. Conclusion This method is simple, rapid and accurate, which can be used as a fast and reliable method for the determination of the lead, cadmium and chromium in instant tea.