甲亚胺测定土壤有效硼的前处理方法研究

Study on pretreatment methods of available boron in soil determinated by methylene amin-H

土壤有效硼测定通常采用甲亚胺-H比色法,该方法前处理(煮沸)过程分析效率低、操作步骤不易掌控,极易给测定结果带来较大误差。为此,以山西省标准土样TCB-2为检测样品,对甲亚胺-H比色法的煮沸提取步骤进行了改进,分别试验了水浴提取、微波提取时间对土壤有效硼测定的影响,确定水浴法最佳提取时间为50 min,微波提取时间为90 s。对国家土壤标准物质GBW07412a检测结果表明,水浴提取和微波提取测定结果与标准参照值符合,相对标准偏差分别为3.43%和8.91%。

Soil available boron is usually determinated using methylene amine-H method （MeA-H）.The procedure of using boiling water to extract available boron from soil samples has to be done before determination.However,this pretreatment method has several disadvantages such as not very efficient,hard to control conditions and easy to bring errors.In this paper,the extracting procedure of MeA-H for sample TCB-2 was improved using water bath or microwave.The optimized extraction time was 50 minutes and 90 seconds for water bath and for microwave respectively.The two improved extraction methods were applied to analyze available boron for national standard reference soil sample （GBW07412a）,and satisfied results were achieved using both water bath and microwave.The RSD of 5 replicates were 3.43% and 8.91%,respectively.