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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 acid leaching - graphite furnace atomic absorption spectrometry determination of cadmium in rice. Methods 80 mesh sieved rice samples were directly diluted with 0.5% nitric acid solution, shake well and stand for 30 min, the supernatant on the machine sampling, graphite furnace atomic absorption spectrometry determination of cadmium in rice. The results of the test, the best screening mesh is 80 mesh, the best extraction acidity of 0.5%, the best standing time of 30 min, the best extraction temperature of 25 ℃. The precision of this method is 4.67% ~ 7.56%. The measured result of rice standard substance GBW10010 is within the standard value range. There was no significant difference between the results of ordinary samples and the results of microwave digestion (paired sample t test, t = -1.081, P> 0.05), indicating that the acid extraction of cadmium from rice was enough. Conclusion The method has the advantages of no digestion, fast and convenient, cost saving, reliable results, etc. It can be widely applied to the detection of cadmium in rice.