直观回流双位加热消解法在土壤重金属元素分析中的应用

Application of visible reflux double-control heating and digestion method in analysis of heavy metal element in soil

【目的】建立一种直观、环保、快速的消解和测定土壤中重金属元素的新方法,以减少样品消解的污染环节,并提高分析效率。【方法】利用聚四氟乙烯双位消解管及双位消解仪的透视和分层加热功能,分别进行酸回流、消解温度、消解时间、方法比对试验,测定待测溶液中的铜、锌、铅、镉、铬元素浓度。【结果】双位消解仪的分层加热模式能够回流消解样品,减少酸用量,降低试验空白值,缩短样品消解时间,快速除酸,且其封闭式消解过程避免了环境粉尘对消解管内样品溶液的污染,极大提高分析效率和结果精密度。此外,双位消解仪和消解管的透视功能使样品消解过程始终处于直观的受控状态,避免了样品消解不完全、被蒸干或剩余酸过多等的现象,有效提高分析结果的可靠性。采用直观回流双位加热消解法所测定的基地土壤样品重金属元素含量均在标准值范围内,加入标准的回收率为98%-101%,相对标准偏差〈5.0%。【结论】直观回流双位加热消解法是一种环保、安全和高效的土壤样品消解新方法,此方法消解和测定土壤中重金属含量的结果精确度和准确性较高,值得大力推广应用。

【Objective】The present study was conducted to establish a visible,environmental friendly and rapid method of digestion and detection for heavy metal element in soil which could decrease pollution sections during sample digestion and raise analysis efficiency.【Method】 PTFE double-control digestion tube and functions of perspective and layered heating of double-control digestion instrument were applied in the study to detect concentrations of Cu,Zn,Pb,Cd,Cr elements in tested solution by analyzing results of acid reflux,digestion temperature,digestion time and method comparison.【Result】Results showed that,layered heating mode of double-control digestion instrument could achieve the reflux of digestion sample,reduce consumption of acid and decrease the appearance of experiment blank values,shorten digestion time of the sample,realize rapid deacidification.Its closed digestion process prevented environmental dust from polluting the sample solution in the digestion tube and greatly increased the analysis efficiency and the precision of the results.In addition,the perspective function of double-control digestion instrument and digestion tube made the whole process of digestion of the sample be visible and under control,which prevented the sample from incomplete digestion,be dried by distillation or leaving too much acid,etc.Thus,such method greatly increased the reliability of the results.Standard recovery rate was 98%—101%,relative standard deviation（RSD）〈5.0%.【Conclusion】 Visible reflux double-control heating and digestion method is an environmental friendly,safe and efficient new method to digest soil sample.Using such method in digesting and detecting heavy metal contents in soil can obtain accurate and precise result.Therefore,Visible reflux double-control heating and digestion method worthy being promoted.