基于能量色散X射线荧光光谱技术 检测大米中镉的研究

建立了基于能量色散型X射线荧光光谱(Energy dispersive X-ray fluorescence spectrometry,EDXRF)技术检测大米中镉的方法。将大米进行前处理,对大米粒径、检测时间、压片压力、含水量和大米质量这5个条件参数进行优化,从精密度、重复性、稳定性和加标回收率4个方面进行方法学评价。结果表明,最优条件为:大米粒径140目,检测时间180 s,压片压力40 MPa下压制30 s,含水量<5%,大米质量5.00 g。EDXRF法精密度、重现性、稳定性的相对标准偏差分别为0.11%、0.05%、0.45%,平均加标回收率为114.8%,加标量在0.1~0.5 mg/kg时,相关系数为0.9982。最后对EDXRF法和石墨炉原子吸收光谱法测量结果进行比较,相关系数达到0.9814。说明新建立的EDXRF方法能够满足快速检测的要求。

Detection of Cd in Rice Based on Energy Dispersive X-ray Fluorescence Spectrometry

A method for detecting cadmium in rice based on energy dispersive X-ray fluorescence spectrometry(EDXRF)was established. The rice was pretreated,and the five parameters of rice particle size,detection time,tableting pressure,water content and rice quality were optimized,and academic evaluation was carried out in terms of precision,repeatability,stability and spike recovery. The results showed that the optimal conditions were:Rice with a diameter of 140 mesh,detection time of 180 s,compression at 40 MPa for 30 s,water content<5%,and rice mass 5 g. The relative standard deviations of precision,reproducibility and stability of EDXRF method were 0.11%,0.05% and 0.45%,respectively. The average spike recovery was 114.8%. When the spiked amount was 0.1~0.5 mg/kg,the correlation was related. The coefficient was 0.9982.Finally,the results of EDXRF and graphite furnace atomic absorption spectrometry were compared. The correlation was very good and the correlation coefficient reached 0.9814.It indicates us that the newly established EDXRF method can meet the requirements of fast detection.