石墨炉原子吸收法测定蒙古黄芪中铅的探讨

Determination of trace lead in Astragalus membranaceus(Fisch.) Bge. var. mongho licus(Bge.)Hsiao by graphite furnace atomic absorption spectrometry

目的:建立石墨炉原子吸收光谱法测定蒙古黄芪中微量铅的方法。方法:用石墨炉原子吸收法测定蒙古黄芪中微量铅,选择硝酸+过氧化氢(1∶1)为消化酸,1%磷酸二氢铵+硝酸镁(1∶1)为基体改进剂,灰化温度850℃,原子化温度1 950℃。结果:该方法测定铅的检出限为0.732 9 ng/m L,标准曲线的线性相关系数为0.998 3,相对标准偏差为7.895%,用该方法测定标准物质柑橘叶GBW10020(GSB-11)中铅含量为(8.916±0.105 9)μg/g,在标准值(9.7±0.9)μg/g范围内。结论:该方法测定蒙古黄芪中的铅,灵敏度高,选择性好,精密度和准确度均符合要求,应用于蒙古黄芪样品中微量铅的测定,结果令人满意。

Objective： to establish the graphite furnace atomic absorption spectrometric method for determination of trace lead in Astragalus membranaceus（ Fisch.） Bge. var. mongho licus（ Bge.） Hsiao. Methods： Determination of trace lead was conducted in samples using graphite furnace atomic absorption spectrometry. Nitric acid and hydrogen peroxide（ 1∶ 1） were selected as the mixed digestive acid. 1 % ammonium biphosphate and magnesium nitrate（ 1∶ 1） as the matrix modifier were added in the digestion stage. Ashing temperature was 850 ℃. Atomization temperature was 1950 ℃. Results： The method exhibited a detection limit of 0. 7329 ng / m L and the linearly dependent coefficient of 0. 9983,with RSDs of 7. 895 %. Lead content in standard substance of citrus leaves GBW10020（ GSB-11） determined by this method was 8. 916 ±0. 1059 μg / g,within the standard value（ 9. 7 ± 0. 9） μg / g. Conclusion： The method for determination of trace lead in Astragalus membranaceus（ Fisch.） Bge. var. mongho licus（ Bge.） Hsiao findings will provide useful evidences for the high sensitivity and the better selectivity. The method＇s precision and accuracy can meet the requirements,which was used with satisfactory results.