ICP-AES法测定柚子不同部位中多种微量元素

采用电感耦合等离子体原子发射光谱法测定了柚子中多种微量元素,考查了广东、广西及赣州三种产地的柚子中15种元素的含量以及它们在果肉、表皮、内皮及籽中的分布情况.分析结果的相对标准偏差为0.4%～5.01%,平均回收率在87.0%～115.0%之间.该方法简单、快速、可靠、灵敏度高,且多元素可同时测定,能满足实际样品分析要求.实验表明,柚子中含有丰富的对人体有益的Ca,Mg,Fe,Zn,Mn,Cu和Na等元素,相对有害元素Be,Pb,Bi,Cd和As含量很少.不同产地的柚子及柚子的不同部位其元素含量存在差异,大部分元素在果肉中的含量相对柚子中其他部位的含量较低;B,Ba,Ca,Sr和Mn在果皮的含量总体相对高;Cu,Zn和Mg在籽中含量最高,其中各元素在表皮与内皮中的含量差异不大.这种差异可能与植物生长的外在环境和土壤类型有关,如土壤的pH值、本身所含的矿物质及后天灌溉所施肥料、水分等.用ICP-AES测定柚子中微量元素对此资源的充分利用具有重要的指导意义.

Determination of Trace Elements in Different Parts of Grapefruit by ICP-AES

In the present paper, a method of simultaneous determination of trace elements in grapefruit was developed by using inductively coupled plasma-atomic emission spectrometry together with HNO3-HClO4 digestion. The contents of fifteen elements, including B, Ba, Ca, Cu, Zn, Mg, Sr, Mn, Fe, Na, Be, Pb, Bi, Cd and As, were determined in four parts, namely flesh, scarfskin, endodermis and seed collected from Guangdong, Guangxi and Ganzhou, respectively. The relative standard deviations for all these elements in this method were between 0.22% and 5.54%, and the recovery rates were between 87.0% and 115.0%. The measuring method was proved to be simple, rapid, reliable, and highly sensitive. In addition, the determination of these fifteen elements can be carried out at the same time, which can meet the requests of actual sample analysis. The experimental results showed that some beneficial elements to human such as Ca, Mg, Fe, Zn, Mn, Cu and Na in grapefruit were abundant, while some comparatively harmful elements (Be, Pb, Bi, Cd and As) were not detected. Regional differences and partial differences obviously existed in the concentrations of one or more trace elements in grapefruit. As a whole, the concentrations of most elements in flesh were much lower than in other parts of grapefruit. The concentrations of B, Ba, Ca, Sr and Mn were comparatively higher in the seed capsule than in other parts. Cu, Zn and Mg had the highest concentrations in seed compared to other parts. There was little difference between scarfskin and endodermis. And as for the regional differences, the contents of Mn, Zn and Na in Gannan pomelo in all its parts were higher than those in other regions, and the contents of Ba in Guangdong pomelo in all its parts were higher than those in others, while Guangxi pomelo had the highest Fe content. These differences might resulted from the natural environmental conditions such as temperature, humidity, soil types with different pH, the mineral composition or concentration, and so on. Application of fertilizer and prunning might be an important man-made factors which could also result in the differences. The determination of these elements by using ICP-AES has important point for exploiting grapefruit fully in future.