氢化物发生原子荧光光谱法测定粮食硒的方法学研究及应用

A method for detection of selenium in grain by hydride generation-atomic fluorescence spectrometry and its application

目的建立快速、简便、准确的粮食硒元素含量测定方法。方法选择硝酸和高氯酸混合酸（体积比为7∶3）在电热板上加热消化粮食样品，采用氢化物发生原子荧光光谱法测定粮食中硒含量，分析新方法检出限、精密度、准确度（回收率、方法特性实验和方法对照实验），并应用新方法测定山东省粮食样品。结果应用新方法测定粮食硒的最低检出限为4 μg/kg，相关系数为0.999 9；精密度：日内相对标准偏差（RSD）为1.32%，日间RSD为4.17%；准确度：平均回收率分别为104.0%、99.0%、98.4%（n = 6），总平均回收率为100.5%（范围为96.7%-105.5%）；新方法对玉米标准物质的测定值[（0.022 ± 0.006）mg/kg]在标准值[（0.021 ± 0.008）mg/kg]范围内；对样品的测定结果[（0.424 ± 0.096）mg/kg]与国标荧光法[（0.406 ± 0.108）mg/kg]一致；山东省5个地区小麦、玉米、地瓜样品中硒含量测定值分别为山亭：（0.030 3 ± 0.025 2）、（0.016 8 ± 0.013 5）、（0.015 4 ± 0.002 9）mg/kg；安丘：（0.020 3 ± 0.000 1）、（0.020 4 ± 0.009 9）、（0.017 1 ± 0.007 5）mg/kg；莒南：（0.021 3 ± 0.013 9）、（0.018 5 ± 0.007 8）、（0.019 9 ± 0.003 6）mg/kg；沂水：（0.025 7 ± 0.006 2）、（0.020 6 ± 0.003 2）、（0.018 2 ± 0.003 2）mg/kg；五莲：（0.020 3 ± 0.004 7）、（0.020 1 ± 0.008 9）、（0.018 4 ± 0.007 3）mg/kg。结论新方法耗时少、污染少、用酸量少、操作简单易行，精密度、准确度均较高，适用于疾病防治及科研工作中大批量粮食样品硒含量的测定。

ObjectiveTo establish a rapid, simple and accurate method for detection of selenium in grain that is suitable in Chinese situation.MethodsNitric acid and perchloric acid （7：3, v/v） were used to digest the grain samples by heating on a hot plate. Selenium was determined with hydride generation atomic fluorescence spectrometry. Sample detection limit, precision, accuracy （recovery, method characteristics and method control） were studied. And the grain samples of Shandong Province were determined by this method.ResultsThe lowest detection limit was 4 μg/kg. The coefficient of correlation of working curve was 0.999 9. Intra-day precision was 1.32%, day precision was 4.17%. The total average rate of recovery was 100.5% with a range of 96.7%-105.5%, and the average rates of recovery were 104.0%, 99.0% and 98.4% （n = 6）. The determination results of corn reference material [（0.022 ± 0.006） mg/kg] were in the standard value range[（0.021 ± 0.008） mg/kg]. The determination results of the samples [（0.424 ± 0.096） mg/kg] were consistent with the results of national standard fluorescence method [（0.406 ± 0.108） mg/kg]. The contents of selenium in wheat, maize and sweet potato samples from five regions of Shandong Province were： Shanting： （0.030 3 ± 0.025 2）, （0.016 8 ± 0.013 5）, （0.015 4 ± 0.002 9） mg/kg; Anqiu： （0.020 3 ± 0.000 1）, （0.020 4 ± 0.009 9）, （0.017 1 ± 0.007 5） mg/kg; Ju＇nan： （0.021 3 ± 0.013 9）, （0.018 5 ± 0.007 8）, （0.019 9 ± 0.003 6） mg/kg; Yishui： （0.025 7 ± 0.006 2）, （0.020 6 ± 0.003 2）, （0.018 2 ± 0.003 2） mg/kg; Wulian： （0.020 3 ± 0.004 7）, （0.020 1 ± 0.008 9）, （0.018 4 ± 0.007 3） mg/kg.ConclusionsThe method has the advantages of higher precision and accuracy, less time, less pollution, less aciduse, easier operation and repeatability. It is very suitable for measuring selenium content in large amount of food samples.