抑制植物样品消解过程中硒挥发的方法  

A Method for Suppressing Volatile Loss of Selenium in Digestion of Plant Samples

作　　者：陈海杰[1] 马娜[1] 陈卫明[1] 顾雪 张鹏鹏 张灵火 白金峰[1] 于兆水[1] CHEN Hai-Jie;MA Na;CHEN Wei-Ming;GU Xue;ZHANG Peng-Peng;ZHANG Ling-Huo;BAI Jin-Feng;YU Zhao-Shui(Key Laboratory of Geochemical Exploration,Ministry of Natural Resources,Institute of Geophysical and Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China)

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,自然资源部地球化学探测重点实验室,廊坊065000

出　　处：《分析化学》2020年第9期1268-1272,共5页Chinese Journal of Analytical Chemistry

基　　金：地质调查项目(No.DD20190522);国家重点研发计划项目(No.2016YFC0600601);物化探所中央级公益性科研院所基本科研业务费专项(No.AS2020J07)资助。

摘　　要：氢化物发生-原子荧光光谱法(HG-AFS)是测定植物样品中硒(Se)的理想方法,但植物样品中Se在消解过程中容易挥发损失,而使结果偏低。Se标准溶液采用HCl、HF、HClO4消解时,加热至蒸干后,Se会挥发损失,而单独采用HNO3消解时不会挥发损失,表明Se的挥发可能与F、Cl的存在有关。本研究发现,Ca^2+可以有效抑制Se的挥发损失,基于此建立了HG-AFS测定植物样品中痕量Se的分析方法。取0.5000 g植物样品,加入8mL 0.015 g/mL Ca^2+,采用HNO 3-HClO 4(15∶2,V/V)混合液于低温电热板进行消解,加热至蒸干,Se也不会挥发损失。考察了Ca^2+对于共存干扰元素允许量的影响,发现加入Ca^2+后,共存干扰元素的允许量并未发生明显变化。本方法检出限为4.95 ng/g,精密度达到2.56%~3.17%,采用不同类型的植物标准物质验证,测定值与标准值吻合。Hydride generation-atomic fluorescence spectrometry is an ideal tool for determination of selenium(Se).But the detection results of Se in the plant samples were lower due to the volatilization loss in the digestion process.Our experiments found the volatilization loss of Se when the standard solution was digested with HCl,HF and HClO4,and heated to dryness,but there was no loss when it was digested with HNO3 alone,indicating that the volatilization may be related to the existing of F and Cl.In this study,a new method was proposed,which could effectively inhibit the volatilization of Se by adding Ca^2+.After adding 8 mL 0.015 g/mL Ca^2+to 0.5000 g plant samples and digesting with the mixed solvent of HNO 3-HClO 4(15∶2,V/V)on low temperature heating plate,Se was not volatilized even after the solution was heated to dryness.Simultaneously,it was found that the addition of Ca^2+could not affect the allowable amount of the co-existing interference elements.The detection limit of the method was 4.95 ng/g,and the precision was 2.56%-3.17%.The determined values for the different reference materials of plant were in agreement with the certified values.

关 键 词：氢化物发生-原子荧光光谱法 痕量硒 植物样品 挥发 损失 

分 类 号：O657.31[理学—分析化学] Q94-33[理学—化学]