São Paulo State University, Analytical Chemistry Department, P.O. Box 355, 14801-970 Araraquara, SP, Brazil.
Talanta. 2012 Oct 15;100:21-6. doi: 10.1016/j.talanta.2012.08.038. Epub 2012 Sep 1.
A procedure is proposed for Pb determination in medicinal plants by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) using direct solid sampling. Among Pd(NO(3))(2), Pd/Mg(NO(3))(2), NH(4)H(2)PO(4) and the W-coated platform tested as chemical modifiers, Pd(NO(3))(2) presented the best performance. Calibration plots (10-1000 pg Pb) with regression coefficients better than 0.999 were typically obtained. Accuracy was checked for Pb determination in five plant certified reference materials. Results were in agreement with reference values at a 95% confidence level (paired t-test). Medicinal plant samples were analyzed by the proposed procedure and line-source GF AAS using slurry sampling as a comparative technique. The RSD was 10% (n=3) for a sample containing 0.88 μg g(-1) Pb. The limit of quantification (dry mass) was 0.024 μg g(-1). The contents of Pb in medicinal plant samples varied in the 0.30-1.94 μg g(-1) range.
提出了一种采用直接固体进样、高分辨连续光源石墨炉原子吸收光谱法（HR-CS GF AAS）测定药用植物中 Pb 的方法。在 Pd(NO(3))(2)、Pd/Mg(NO(3))(2)、NH(4)H(2)PO(4)和涂 W 的平台等测试的化学改性剂中，Pd(NO(3))(2)表现出最佳性能。典型地获得了 Pb 校准曲线（10-1000 pg），其回归系数优于 0.999。用 5 种植物标准参考物质对 Pb 测定的准确性进行了检查。在 95%置信水平（配对 t 检验）下，结果与参考值一致。用所提出的程序和浆进样线源 GF AAS 分析了药用植物样品，将浆进样作为比较技术。对于含有 0.88 μg g(-1) Pb 的样品，RSD 为 10%（n=3）。定量限（干质量）为 0.024 μg g(-1)。药用植物样品中 Pb 的含量在 0.30-1.94 μg g(-1)范围内变化。
