微波辅助萃取-反相液相色谱-电感耦合等离子体质谱法测定玉米中4种砷形态的含量  

Determination of 4 Arsenic Species in Corn by Reversed Phase Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry with Microwave Assisted Extraction

作　　者：陈曦 周明慧 张洁琼 伍燕湘 田巍 王松雪 CHEN Xi;ZHOU Minghui;ZHANG Jieqiong;WU Yanxiang;TIAN Wei;WANG Songxue(Academy of National Food and Strategic Reserves Administration,Beijing100037,China)

机构地区：[1]国家粮食和物资储备局科学研究院,北京100037

出　　处：《理化检验（化学分册）》2022年第8期877-882,共6页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：国家重点研发计划项目(2017YFC1601300)。

摘　　要：玉米样品经粉碎、过筛后,分取0.5g,加入0.15mol·L^(-1)硝酸溶液7mL,置于微波消解仪中,分别在80,100,120℃下消解10,10,15min。离心10min,上清液过0.22μm有机滤膜,滤液进入液相色谱仪,在Agilent ZORBAX SB-Aq反相色谱柱上用5mmol·L^(-1)己烷磺酸钠-20mmol·L^(-1)柠檬酸的混合溶液(pH 4.3)进行等度洗脱,分离后的4种砷形态{一甲基砷(MMA)、二甲基砷(DMA)、三价砷[As(Ⅲ)]和五价砷[As(Ⅴ)]}用电感耦合等离子体质谱仪测定。结果显示:4种砷形态可在4min分离完全,质量浓度在2~50μg·L^(-1)内与其对应的信号强度呈线性关系,检出限(3S/N)为0.041~0.054μg·L^(-1);对空白玉米样品进行3个浓度水平的加标回收试验,4种砷形态回收率为94.2%~102%,测定值的相对标准偏差(n=6)小于3.0%;方法用于3个天然污染玉米样品的分析,4种砷形态均有检出,其中As(Ⅲ)、As(Ⅴ)的检出量较高。After corn sample was screened and sieved,an aliquot(0.5g)was taken and mixed with 7mL of 0.15mol·L^(-1) nitric acid solution.The mixture was placed into microwave digestion apparatus,and digested at 80,100,120℃for 10,10,15 min,respectively.The supernatant was passed through a 0.22μm organic filter membrane after centrifuging for 10min.The filtrate was introduced into the liquid chromatography,and the mixed solution(pH 4.3)of 5mmol·L^(-1) sodium hexanesulfonate-20mmol·L^(-1) citric acid was used for isocratic elution on the Agilent ZORBAX SB-Aq reversed phase chromatographic column.The 4arsenic species[MMA,DMA,As(Ⅲ),As(Ⅴ)]were determined by inductively coupled plasma mass spectrometry.It was shown that the 4 arsenic species could be separated completely within 4 min;the linear relationships between values of mass concentration and signal intensity were kept in the range of 2-50μg·L^(-1) ,and the detection limits(3S/N)were 0.041-0.054μg·L^(-1) .Test for the spiked recovery was made on blank corn samples at three concentration levels,giving values of recovery in the range of 94.2%-102%,and RSDs(n=6)of the determined values were less than 3.0%.The proposed method was applied to the analysis of the 3naturally polluted corn samples,and the 4species of arsenic were all detected,among which the detection amounts of As(Ⅲ)and As(Ⅴ)were higher.

关 键 词：微波辅助萃取 反相液相色谱-电感耦合等离子体质谱法 砷形态 无机砷 玉米 

分 类 号：O657.63[理学—分析化学]