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

摘要

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(Ⅱ)和Cd(Ⅱ)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0.006 μg/L,相对标准偏差为32％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 |xg/L and 0. 006 |xg/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.