热水浴浸提-电感耦合等离子体发射光谱法测定土壤中有效硼

Determination of Available Boron in Soil by ICP-OES with Hot Water Bath Extraction

目前土壤有效硼分析方法主要有分光光度法和电感耦合等离子体发射光谱法(ICP-OES)。分光光度法流程长、操作繁琐,分析效率较低且易带来环境污染,对分析人员的经验要求高,测定结果不稳定。现有的ICP-OES法主要有浸提时间长、浸提温度高等缺点,对大批量样品分析效率低、浪费电能且操作时存在烫伤危险。本文使用聚乙烯具塞塑料瓶代替石英锥形瓶加回流装置,加入超纯热水作为浸提剂,在热水浴中浸提后使用ICP-OES法测定有效硼的含量。通过实验确定了最佳提取条件为:使用85℃超纯热水作为浸提剂,土液比1∶2,水浴浸提温度85℃,浸提时间6min,趁热离心后使用ICP-OES法测定有效硼含量。方法检出限为0.02mg/kg,相对标准偏差(RSD,n=12)小于3%,对土壤有效态成分分析标准物质NSA-1、NSA-2、NSA-3、NSA-6以及GBW07497(HTSB-5)、GBW07498(HTSB-6)进行实验,有效硼测定结果相对误差均小于4%,与标准值基本相符。

BACKGROUND:At present,the main methods of soil available boron analysis are spectrophotometry and inductively coupled plasma-optical emission spectrometry(ICP-OES).The spectrophotometric method has a long process,cumbersome operation,low analysis efficiency and easy environmental pollution,high requirements on the experience of the analyst,and unstable measurement results.The existing ICP-OES method has shortcomings such as long extraction time and high extraction temperature.It has low efficiency in analyzing large quantities of samples,wastes electrical energy and has the risk of scalding during operation.OBJECTIVES:In order to improve the ICP-OES method with water bath extraction for determination of available boron in soil.METHODS:The polyethylene stoppered plastic bottle was used instead of a quartz conical flask and a reflux device.Ultrapure hot water was added as the extractant.After leaching in a hot water bath,the ICP-OES method was used to determine the available boron content.RESULTS:The optimal extraction conditions were determined through experiments:using 85℃ultrapure hot water as the extractant,soil-liquid ratio of 1∶2,water bath extraction temperature of 85℃,extraction time of 6min,using ICP-OES method after hot centrifugation to determine the available boron content.The detection limit of the method was 0.02mg/kg,the precision(RSD,n=12)was less than 3%,and the standard substances NSA-1,NSA-2,NSA-3,NSA-6 and GBW07497(HTSB-5)and GBW07498(HTSB-6)were tested,and the relative errors of the measurement results were all less than 4%,which was consistent with the recommended value.CONCLUSIONS:This method can be used to determine available boron in soil with quick,efficient,safe and cost-effective potentials.