石墨烯/二氧化钛复合材料富集-石墨炉原子吸收光谱法测定铅和镉

Determination of Pb(Ⅱ) and Cd(Ⅱ) by Graphite Furnace Atomic Absorption Spectrometry after Preconcentration with Graphene-Titanium Dioxide Composites

以石墨烯/二氧化钛复合材料为吸附剂,结合石墨炉原子吸收光谱法,建立了Pb？和Cd？的检测方法。优化的实验条件为：溶液pH=5.0,吸附时间为60 min,吸附剂用量为0.02 g。结果表明：吸附过程符合拟二级动力学反应模型;吸附反应是吸热过程。建立的石墨烯/二氧化钛复合材料富集-石墨炉原子吸收光谱法对Pb2＋和Cd2＋的检出限分别为0.086和0.006μg/L,相对标准偏差为3.2%和2.5%。将本方法应用于矿石标准样品的测定,测定结果与标准值相符;用于茶叶实际样品的测定,回收率为96.8%~105.0%。

A method for the determination of lead and cadmium was developed with graphene-TiO2 composites （GN-TiO2） as adsorbents combined with graphite furnace atomic absorption spectrometry. Effects of various experimental conditions on the adsorption capacity were investigated. The optimized conditions were： sample pH as 5.0, contact time as 60 min, and adsorbent dosage as 0.02 g. Results showed that the processes could be simulated by a pseudo-second-order model. The adsorption process was proved to be an endothermic one. LODs of lead and cadmium of the developed method were calculated as 0.086 Ixg/L and 0.006 Ixg/L with RSDs of 3.2% and 2.5%, respectively. Furthermore, the present method was applied to the determination of lead and cadmium in different reference materials and real tea samples with satisfactory results.