大米粉比对考核样品中镉含量定值研究  

Certification of Cd in Rice Validation Samples

作　　者：逯海[1] 阚莹[1] 郭敬[1] 纪洁[1] 韦超[1] 卢晓华[1] 孟凡敏[1] 李红梅[1] 

机构地区：[1]中国计量科学研究院,北京100013

出　　处：《质谱学报》2013年第3期163-169,共7页Journal of Chinese Mass Spectrometry Society

基　　金：国家质检总局质检公益行业专项(2012104001);中国计量科学研究院基本业务费基金(21-JB1250)资助

摘　　要：大米是我国居民的传统主食之一,其安全与否关乎民生。针对一些地区存在大米镉污染的现象,本工作制备了4种大米的系列比对考核样品,并测定了其中的镉含量。制备过程采用气流粉碎、混匀技术;定值则采用同位素稀释质谱法,定值结果与标准加入法相核验,获得了量值分别为(149.5±3.8)、(181.8±5.1)、(387.4±9.3)、(436.8±13.6)μg/g的4种比对考核样品;其不确定度评定考虑了定值过程、样品的不均匀性及不稳定性等各因素。定值过程中,着重研究了Sn核素及Zr、Mo等氧化物对Cd测量的干扰。研究发现:112Sn对112 Cd、114Sn对114 Cd的质谱干扰、Zr的氧化物对112 Cd产生质谱干扰均可忽略不计;4个样品中Mo含量较高且浓度不同,同时样品中112 Cd/111 Cd、114 Cd/111 Cd接近天然镉的同位素比值。说明无论是112Sn、96Zr16 O、96 Mo16 O、95 Mo16 O对112 Cd、111 Cd的影响均不大,但其引入的不确定度应予考虑。Rice is one of the traditional Chinese foods and its safety is important to Chinese people. Currently, Cd contamination in rice is a serious problem in China. In this paper, 4 rice matrix samples were developed. During preparation airflow crushing technique was ap- plied. Furthermore, IDMS was applied for certification and external addition method was used for validating the results. During certification, isobars based on Sn, Zr, Mo et al were studied. The results show that isobars of 112Sn on 112Cd, 1148n on 114Cd and 9SZrl60 on 112Cd, 96Mo16O, 9SMo16O on 112Cd, 111Cd can be neglected, respectively, but the uncertain- ties derived from isobars will be taken into 3.8）μg/g,（181.8±5. 1）μg/g, （387.4±9.3）μg/g, （436.8±13.6）μg/g, respectively areavailable. The uncertainties derived from certification, homogeneity test, stability test are taken account into the combined uncertainties.

关 键 词：镉 大米 同量异位素干扰 同位素稀释质谱 

分 类 号：O657.63[理学—分析化学]