熔融制样-X射线荧光光谱法测定土壤矿质全量元素

Determination of Total Mineral Elements in Soil by X-ray Fluorescence Spectroscopy with Melting Sample Preparation

由于土壤矿质基体复杂,总碳含量高。为了能够同时测定土壤矿质全量元素,选择Li_(2)B_(4)O_(7)-LiBO_(2)-H_(3)BO_(3)(m∶m∶m=45∶10∶5)混合熔剂,LiBr溶液作脱模剂,在高频熔样机上制备熔融样片,建立了熔融制样-波长色散X射线荧光光谱法(WD-XRF)测定土壤矿质全量元素Si、Mg、Fe、Al、Ca、K、Na、P、Mn、Ti含量的方法。实验表明,混合熔剂与样品稀释比为10∶1,加入5滴LiBr溶液(400 g/L),熔融温度为1 050℃,熔融时间为9 min,助熔剂中H_(3)BO_(3)促使土壤中CaCO_(3)、MgCO_(3)快速反应,迅速释放出CO_(2),制备出流动性好、分布均匀、表面透明、平整、无气泡的熔融样片。在最佳测量条件下,选择土壤成分分析标准物质、岩石成分分析标准物质、水系沉积物成分分析标准物质等进行互配,采用基本参数法校正基体效应后,建立校准曲线。方法的检出限为6.71~257μg/g,测定结果相对标准偏差(RSD,n=11)为0.12%~0.51%。采用实验方法对土壤国家有证标准物质GBW07466、GBW07544、GBW07555进行分析,测定结果与认定值相符。

Due to the complex mineral matrix of soil,the total carbon content is high.In order to simultaneously determine the total amount of soil mineral elements,a mixed flux of Li_(2) B_(4) O_(7)-LiBO_(2)-H_(3) BO_(3)(m∶m∶m=45∶10∶5)was selected,and LiBr solution was used as a release agent to prepare molten samples on a high-frequency melting prototype.A method for determining the total amount of soil mineral elements Si,Mg,Fe,Al,Ca,K,Na,P,Mn,Ti content using melting sample preparation wavelength dispersive X-ray fluorescence spectroscopy(WD-XRF)was established.The experiment showed that the dilution ratio of the mixed flux to the sample was 10∶1,and 5 drops of_(4)00 g/L LiBr solution were added.The melting temperature was 1050℃,and the melting time was 9 minutes.H_(3) BO_(3) in the flux promoteed the rapid reaction of CaCO_(3) and MgCO_(3) in the soil,rapidly releasing CO_(2) and preparing a molten sample with good fluidity,uniform distribution,transparency,flatness,and no bubbles.Under the optimal measurement conditions,the soil composition analysis standard materials,rock composition analysis standard materials,and water sediment composition analysis standard materials for mutual were selected to match each other.After the matrix effect was corrected by the basic parameter method,the calibration curve was established.The detection limit of the method was 6.71—257μg/g,the relative standard deviation(RSD,n=11)was 0.12%—0.51%.The national certified reference materials GBW07466,GBW07544,and GBW07555 for soil were analyzed using experimental methods,and the determination results were consistent with the recognized values.