振荡提取和超声提取用于土壤样品中元素形态分析

Morphological Analysis of Elements in Soils Using Mechanical Shaking Extraction and Ultrasonic Vibration Extraction

采用振荡提取和超声提取两种提取方式对土壤样品中Cu、Pb、Zn、Co、Ni、Cr、Cd、Mn、As、Sb、Hg、Se等12种元素形态分析进行了实验,对超声提取时间进行了详细研究,比较了振荡提取和超声提取的精密度和准确度。结果表明,在元素离子交换态(包含水溶态)、碳酸盐结合态、腐殖酸结合态、铁锰氧化物结合态提取中,采用超声提取技术可以大大减少提取时间,总提取时间仅为3.2 h,工作效率比振荡提取提高5倍。超声提取的精密度优于振荡提取,方法精密度为3.1%～34.8%(n=12),准确度(各态量之和与全量相对误差)为0.34%～11.85%,准确度、精密度均能满足《生态地球化学评价样品分析技术要求》(DD 2005-03)》。超声提取条件更易掌握和控制,方法简单快速,适合于批量样品分析,已用于分析数万件生态地球化学评价样品。该方法已列入DD2005-03中,为指定的多目标区域地球化学调查土壤样品形态分析方法。

Two methods of mechanical shaking extraction and ultrasonic vibration extraction have been tested for chemical morphological analysis of Cu,Pb,Zn,Co,Ni,Cr,Cd,Mn,As,Sb,Hg and Se in soil samples.Extraction time by ultrasonic vibration extraction has been studied in detail,and the precision and accuracy were compared between mechanical shaking extraction and ultrasonic vibration extraction.The results indicate that ultrasonic extraction technology can greatly reduced extraction time to 3.2 h for elements that characterize ion exchange bond phase（contains a water-soluble state）,carbonate bond phase,humic acid bond phase and iron manganese oxides bond.Efficiency of utrasonic vibration extraction was 5 times that of mechanical shaking extraction.The precision and accuracy（relative errors between the sum of elements content in every phase and total contents in samples） of ultrasonic vibration extraction were RSD 3.1%-34.8%（n=12） and 0.34%-11.85%,respectively,which were superior to mechanical shaking extraction.Accuracy and precision meet the requirements of the China multitarget ecosystem geochemical survey ＂China Geological Survey Bureau Geological Investigation Technology Standard＂（DD 2005-03） for chemical morphological analysis technology.Ultrasonic extraction conditions are easier to handle and control,also the method is simple,fast,convenient and suitable for large numbers of samples analysis.Ultrasonic extraction has been used to analyse ecological geochemical surveys for tens of thousands of samples.This method has been included in the geological survey technical standards of China Geological Survey in DD 2005-03,and specified as the standard method for soil samples analysis in multitarget regional geochemical surveys by the China Geological Survey Bureau.