石墨炉AAS法分析冬青科苦丁茶树系统中镉及其分布

Analysis of Cadmium and Its Distribution in Kudingcha System by GF-AAS

采集海南大学苦丁茶种质资源库中6种冬青科(Ilex)苦丁茶树的根、茎、叶及对应土壤样品,通过试验研究,建立了高压密封消解-石墨炉原子吸收光谱法测定样品中镉的方法。对植物样和土壤样分别采用硝酸-双氧水和硝酸-高氯酸-氢氟酸混酸体系进行消解。以磷酸二氢铵作为基体改进剂,并开启氘灯校正背景,在优化的工作条件下测定样品中镉。该方法的检出限为0.300ng/mL,用于实验样品中镉的测定,其相对标准偏差RSD<5%,加标回收率介于94%～108%之间。用该方法对茶叶(GBW10016)和土壤(GBW-07407)标准参考物中镉进行了测定,测定结果与标准值相符合,相对误差小于7%。冬青科苦丁茶树及其土壤中镉的分布具有特征性,主要表现为:土壤>>茶树,根际土壤>非根际土壤,吸收根>主根或茎,嫩叶>老叶>枯叶。

Root,stem,leaf and corresponding soil samples of 6 kinds of Kudingcha trees in germplasm resource bank of Hainan University were studied by experiment,and high pressure sealed digestion-graphite furnace atomic absorption spectrometry （GF-AAS）was used to determine Cd in samples,with detection limit of 0.300ng·mL-1,RSD less than 5%,recovery test rate between 89%～108%. The method was used to determine standard reference materials of tea and soil,with results in conformity with the standard of GBW10016 and GBW-07407,and relative error less than 5%. Distribution of cadmium in Kudingcha trees and soil was in the order as soil,Kudingcha trees,rhizosphere soil,non-rhizosphere soil,absorbing roots,main root or stem,young leaves,old leaves and dead leaves.