石墨炉原子吸收法测定武汉市售大米中镉含量的研究

摘要

目的：研究石墨炉原子吸收光谱法测定大米中镉含量,并对武汉市售大米中镉含量进行测定分析。方法采用湿法消解对样品进行前处理,测定大米中镉含量的检出限、重复性、回收率和精密度。结果较佳消化条件为大米质量1 g、消化剂包括10 mL硝酸和2 mL过氧化氢、时间12 h。在该试验条件下,石墨炉原子吸收光谱法测定大米中镉含量的检出限为0.051μg/kg,加标回收率为98.85%。大米中镉含量随产区和品种的不同差异显著,湖南、湖北、江西等中南地区的大米镉含量较高,吉林、黑龙江等东北地区的大米镉含量较低；籼米的镉含量高于粳米和糯米,糯米的镉含量高于粳米。结论该方法测定大米中的镉含量准确、试验误差小,重复性好,可以用于大米中镉含量的测定。%ABSTRACT:Objective To investigate the method of graphite furnace atomic absorption spectrometry (GFAAS) to determine the cadmium content in rice, and its application in rice from Wuhan market.Methods Rice was digested by wet digestion for sample pretreatment, the detection limits, precision, repeatability, and recovery rate of GFAAS method were determined under preferred conditions.Results The detection limit of GFAAS method to determine the cadmium content in rice was 0.051μg/kg and the recovery rate was 98.85% under the preferred sample pretreatment conditions, including 1 g rice, 10 mL nitric acid digestion reagent, 2 mL hydrogen peroxide, and 12 h of digestion time. The cadmium content of indica rice was higher than that of japonica rice, and the cadmium content of glutinous rice was higher than that of japonica rice. The cadmium content of rice produced in Hunan, Hubei, and Jiangxi province was higher than that in Jilin and Heilongjiang province.Conclusion This method to determine the cadmium content in rice is accurate and has lower test error and better repeatability under the preferred sample pretreatment conditions, and it can be utilized to determine the cadmium content in rice.