原子吸收法测定枸杞子矿物质元素的三种前处理方法比较

Comparative Study on Three Pretreatment Methods for Atomic Absorptive Spectrophotometry Determination of Metal Elements in Lycium Barbarum

采用干灰化法、HNO_3-H_2O_2湿法消解法和HNO_3-HClO_4湿法消解法分别处理枸杞子样品,利用原子吸收光谱法测定各组样品中Na,K,Ca,Mg,Fe,Cu,Zn,Ni,Pb,Cd十种元素的含量,探讨简单、快捷、准确地测定枸杞子中矿物质元素的前处理方法。结果表明:干灰化法的回收率范围为89.88%~102.15%,标准偏差(RSD)<3.037%;HNO_3-H_2O_2湿法消解法的回收率范围为92.34%~103.21%,标准偏差(RSD)<2.751%;HNO_3-HClO_4湿法消解法的回收率范围为94.52%~102.10%,标准偏差(RSD)<2.496%;三种方法均具有较好的准确度和精密度,但相对于干灰化法和HNO_3-H_2O_2湿法消解法,HNO_3-HClO_4湿法消解法回收效果较好,精密度更高。HNO_3-HClO_4湿法消解法测得Na,K,Ca,Mg元素含量的平均值高于干灰化法和HNO_3-H_2O_2湿法消解法,差异有统计学意义(p<0.05)。此外,HNO_3-HClO_4体系湿法消解法耗时短、消耗试剂量少、消解完全。因而,HNO_3-HClO_4体系湿法消解法可作为原子吸收光谱法测定枸杞子矿物质元素含量较好的前处理方法。

A simple,fast and accurate method was explored to determine the mineralelements in Lycium barbaru.Three different pretreatment methods,including dry ashing method,HNO_3-H_2O_2 and HNO_3-HClO_4 wet digestion,method were employed for digestion of the samples of Lycium barbaru.The concentrations of Na,K,Ca,Mg,Fe,Cu,Zn,Ni,Pb and Cd were determined by using atomic absorption spectrometry.The experimental results showed that the recovery rates of dry ashing method,HNO_3-H_2O_2 and HNO_3-HClO_4 wet digestion method were in the ranges from 89.88%to 102.15%,92.34%to 103.21%and94.52%to 102.10%respectively;the relative standard deviation（RSD） of dry ashing method,HNO_3-H_2O_2 and HNO_3-HClO_4wet digestion method were lower than 3.037%,2.751%and 2.496%separately.The RSD and recovery of three pretreatment methods were all satisfied with the analysis requirements.But compared with dry ashing method and HNO_3-H_2O_2 wet digestion method,the recovery of HNO_3-HClO_4 wet digestion method was better,and the precision was higher.Besides,compared with three pretreatment methods,the average value of Na,K,Ca,Fe and Cd had statistical difference（p0.05）,and HNO_3-HClO_4wet digestion method was significantly higher than others.In addition,HNO_3-HClO_4 wet digestion method taken a shorter time and less consumption of reagents.Therefore,HNO_3-HClO_4 wet digestion method can be used as the preferably pretreatment method for the determination of the contents of metal elements by atomic absorption spectrophotometry method.