快速酸浸提-石墨炉原子吸收法测定大米中镉

Rapid determination of cadmium in rice by acid leaching- GF- AAS

目的建立快速酸浸提-石墨炉原子吸收法测定大米中镉的方法。方法过80目筛得大米样品,以0.5%硝酸溶液直接稀释,充分摇匀后静置30 min,取上清液上机进样,石墨炉原子吸收法测定大米中镉。结果经试验,最佳过筛目数为80目,最佳浸提酸度为0.5%,最佳静置时间为30 min,最佳浸提温度为25℃。本方法精密度为4.67%～7.56%,大米标准物质GBW10010测得结果在标准值范围内。普通样品测得结果与微波消解法测得结果差异无统计学意义（配对样本t检验,t=-1.081,P〉0.05）,说明该法中酸对大米中镉的浸提已经足够完全。结论该法具有无需消解、方便快速、节约成本、结果可靠等优点,可推广应用于大米中镉的检测。

Objective To establish a rapid determination of cadmium in rice by acid leaching graphite furnace atomic absorption spectrometry （GF -AAS）. Methods Passing 80 meshes, rice samples were directly diluted with O. 5% nitric acid solution and shaken well. After standing for 30 minutes, the supernatant of the rice water sample was directly used to determine cadmium by GF - AAS. Results After testing, the best number of meshes is 80, the optimum leaching acidity is O. 5%, the best stand- ing time is 30 min, and the optimum leaching temperature is 25 ~C. The relative standard deviations of this method was 4.67% ~ 7.56%. The measured results of the rice standard substance GBW10010 were within the standard range, and there was no significant difference of the measured cadmium levels of ordinary rice samples between this method and microwave digestion （paired samples t test, t = - 1. 081, P 〉0.05）, indicating that the method of acid leaching of cadmium in rice has been com- pletely adequate. Conclusion This method is characterized by no digestion process, rapid and convenient procedure, cost savings and reliable result. It can be widely used to determine cadmium in the rice.