熔融制样-能量色散X射线荧光光谱仪分析硅酸盐中32 种组分

为充分发挥小型实验室设备的功能,实验采用熔融制样,使用台式能量色散X射线荧光光谱仪(10W, Rh靶)定量分析了硅酸盐样品中的Na₂O、MgO、Al₂O₃、SiO₂、P₂O₅、SO₃、Cl、K₂O、CaO、TiO₂、V、Cr、MnO、Fe₂O₃、Co、Ni、Cu、Zn、Ga、Rb、Sr、Y、Zr、Nb、As、Ba、La、Ce、Th、U、Hf、Pb等32种主、次、痕量组分。对3种不同的解谱方法进行比较,确定Na、Mg、Al、Si、P、As、Ce、Cr、Cu、Ga、La、Nb、Ni、Pb、Th、U、V、Y选择感兴趣区解谱,其余元素用高斯或经改进的高斯函数的最小二乘法拟合解谱。选用有代表性的多个硅酸盐类样品,比较了理论检出限及10次重复测定计算3倍标准偏差得出的检出限,发现以3倍标准偏差作为检出限再取它们的平均值则更具代表性和使用意义。各组分的检出限为0.2~1740μg/g。精密度试验表明,各组分测定结果的相对标准偏差(RSD)为0.12%~10.5%(Na为轻元素,由于含量低,小能谱测定的精密度稍差);对两个土壤标准样品进行正确度验证,测定值与标准值一致。

Determination of thirty-two components in silicate by energy dispersive X-ray fluorescence spectrometer with fusion sample preparation

In order to give full play to the functions of small laboratory instrument, 32 major, minor, trace components in silicate sample (including Na₂O, MgO, Al₂O₃, SiO₂, P₂O₅, SO₃, Cl, K₂O, CaO, TiO₂, V, Cr, MnO, Fe₂O₃, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb,As,Ba, La, Ce, Th, U, Hf and Pb) were quantitatively analyzed using energy dispersive X-ray fluorescence spectrometer (EDXRF). The sample was prepared by fusion sample preparation. The optimization of analysis conditions for elements was focused. Moreover, three different spectrum unfolding methods were compared. The region of interest was selected for spectrum unfolding for Na, Mg, Al, Si, P, As, Ce, Cr, Cu, Ga, La, Nb, Ni, Pb, Th, U, V and Y, while the least squares fitting of Gaussian function or modified Gaussian function was selected for other elements. Several representative silicate samples were used to compare the theoretical detection limit and the detection limit calculated using three times of standard deviation (n=10). It was found that the average of detection limits calculated using three times of standard deviation was more representative and meaningful for use. The detection limits of components ranged from 0.2μg/g to 1740μg/g. The precision tests indicated that the relative standard deviations (RSD) were between 0.12% and 10.5% (Na belonged to light element. The determination precision of small energy spectrometry was poor due to low content). Two certified reference materials of soil were used for accuracy verification, and the found results were consistent with the certified values.