乙醇增敏-电感耦合等离子体原子发射光谱(ICP-AES)法测定土壤中的全硼

Determination of Boron in Soil by Inductively Coupled Plasma Atomic Emission Spectrometry with Ethanol Sensitization

采用电感耦合等离子体原子发射光谱(ICP-AES)法测定土壤中的全硼,具有测定范围宽、精密度高、测定速度快等优点,但其检出限较高,选择乙醇作增敏剂,降低仪器检出限,实现高中低含量样品的同时分析测定。实验表明:当乙醇含量为5%时,雾化效率最佳,原子线B 208.893、B 208.959 nm的灵敏度分别增强了21.2%和18.7%;采用HF-HCl-HNO_(3)消解样品,甘露醇作保护剂,甘露醇的加入可有效解决样品消解过程中硼挥发所导致的测定结果偏低、精密度差等问题。通过对样品最佳消解温度及时间、样品蒸干温度、甘露醇的加入量及消解体系酸用量的考察,结果表明,当甘露醇加入量大于0.02 g时,样品在消解过程中全硼基本无损失,硼元素质量浓度在0.02~2.00 mg/L与其发射光谱强度具有良好的线性关系,相关系数大于0.999,方法检出限为0.4μg/g。按照实验方法对国家标准物质及实际土壤样品进行全硼的分析测定,测定结果相对标准偏差(RSD,n=11)为0.56%~2.1%、相对误差为-2.8%~1.6%、加标回收率在96.8%~105%,可满足日常分析要求。

The determination of total boron in soil by inductively coupled plasma atomic emission spectrometry(ICP-AES)has the advantages of wide determination range,high precision and fast determination speed,but its detection limit is high.In this paper,ethanol was selected as the sensitizer to reduce the detection limit of the instrument and realize the simultaneous analysis and determination of high,middle and low content samples.It was found that when the ethanol content was 5%,the atomization efficiency was the best,and the sensitivity of B 208.893 and B 208.959 nm were increased by 21.2%and 18.7%,respectively.The addition of mannitol can effectively solve the problem of low determination result and poor precision caused by boron volatilization during sample digestion.The optimum digestion temperature and time,the drying temperature of the sample,as well as the amount of mannitol added and the amount of acid in the digestion system were discussed.It was found that when the amount of mannitol was greater than 0.02 g,there was basically no loss of total boron in the digestion process.Boron mass concentration in the range of 0.02—2.00 mg/L had a good linear relationship with its emission spectral intensity,the correlation coefficient was greater than 0.999,and the detection limit of the method was 0.4μg/g.According to this method,the total boron was determined for national standard materials and actual soil samples.The relative standard deviation(RSD,n=11)was 0.56%—2.1%,and the relative error was-2.8%—1.6%.The recovery was 96.8%—105%,which can meet the daily analysis requirements.