微波程序压力消解-逆扩散流动注射化学发光法快速测定枸杞果中的微量铬

为了建立一种快速测定枸杞中微量铬的新方法,将样品经微波程序消解后,用亚硫酸将Cr6+还原为Cr3+,利用逆扩散流动注射分析技术,结合Cr3+对Luminol-H2O2化学发光体系的线性催化作用测定枸杞中总铬含量.结果表明:在最佳条件下,该方法的线性范围为1.0×10-12～1.0×10-7mol/L,相关系数r=0.9991,对1.0×10-7mol/LCr3+,测定的RSD为3.1%(n=11);按3倍标准偏差(3S)计算的检出限为8.64×10-13mol/L,枸杞样品中铬的质量比为8.217μg/g,加标回收率为94.81%～101.54%.该方法快速简便,灵敏度高,选择性好,用于枸杞中微量铬的测定,结果令人满意.

Rapid Determination of Micro Chromium in Medlar Fruits with Pressure Microwave Digestion Procedure by Counter Diffusion Flow Injection Chemiluminescence Method

In order to establish a new rapid determination method for Micro chromium（Cr）in medlar fruits,after the sample was treated by microwave program digestion,Cr^6＋ state was deoxidized to be Cr^3＋ by sulfurous acid.Combined with flow-injection analysis technique,based on Cr^3＋ linear catalysis to Luminol-H2O2 chemiluminescence system,the total content of Cr in medlar fruits was determined.The result indicated that an excellent linear range for chromium determination is 1.0×10^-7～1.0×10^-12 mol/L under the optimal condition,the linear correlation coefficient is 0.999 1.The relative standard deviation of 1.0×10^-7 mol/L Cr^3＋ Standard solution is 3.1 %（n=11）.The lowest detection limit of Cr^3＋ is 8.64×10^-1mol/L.The content of Cr in medlar fruits sample is 8.217 μg/g.The recoveries are in the range of 94.81 %～101.54 %.This method is fast and sensitive with good selectivity.Therefore it can be used to determine the Micro chromium in medlar fruits with satisfactory analytical results.