质量控制图判断石墨炉原子吸收法测定食品中铅时石墨管使用有效期的方法研究

Useful life of graphite tube for determination of lead in food by graphite furnace atomic absorption spectrum with quality control chart

中文关键词:  质控样  质量控制图  石墨管  铅  食品

英文关键词:quality control material  quality control chart  graphite tube  lead  food

中文摘要:

      目的 探讨石墨管性能变化对质控样南瓜粉中铅含量测定的影响, 同时对铅标准溶液和样品消解液有效存放期进行研究。方法 采用石墨炉原子吸收光谱法和质量控制图法测定不同使用次数的石墨管下及不同存放时间的铅标准溶液下质控样中铅的含量。结果 在石墨管使用次数约1800次时, 质控样绿茶(GBW10052(GSB-30))中的铅含量为1.38 mg/kg, 达到质控图的警戒下限。1000 mg/L铅标准储备液在室温或4 ℃密封冷藏时, 至少10个月内可进行质控样中铅的测定, 样品消解液聚四氟乙烯瓶密封保存至少1个月内可进行质控样中铅的有效测定。结论 用质控样绘制质控图的方法可有效监测石墨管有效使用次数, 当质控样铅检测结果接近警戒限时需要更换石墨管。本方法设计合理, 操作简便, 能有效保证食品中铅含量测试的准确和可靠性。

英文摘要:

      Objective To study the effect of graphite tube functional change on determination of lead in quality control material pumpkin powder, and also study the effective reserving time of the lead standard solution and sample digestion solution. Methods Lead content in the quality control material under different times of graphite tube used and different reserving time of the lead standard solution were determined by the method of graphite furnace atomic absorption spectrum(GFAAS) and quality control charts . Results When the graphite tube was used near 1800 times, lead content in the certified reference material green tea (GBW10052 (GSB-30)) was 1.38 mg/kg, which achieved the quality control chart alert threshold. The lead standard stock solution of 1000 mg/L could be stored at room temperature or in 4 ℃ refrigerator for at least 10 month and the digestion solution of the quality control material in poly tetra fluoro ethylene(PTFE) material container could be stored for at least 1 month for lead determination. Conclusion Preparing quality control charts of quality control material can accurately monitor the effective used times of the graphite tube. The graphite tube should be replaced with a new one when the results reach the warning limit of the quality control chart. The method is reasonable, simple, accurate and suitable for the determination of lead in foods.