微波消解-电感耦合等离子体原子发射光谱法测定石灰石中铁铝钙镁钾钠钛

Simultaneous determination of Fe,Al,Ca,Mg,K,Na,Ti in limestone by inductively coupled plasma atomic emission spectrometry with microwave digestion

采用磷酸、硝酸作为消解试剂,利用4工步微波消解石灰石样品,电感耦合等离子体原子发射光谱法测定了石灰石中Fe,Al,Ca,Mg,K,Na,Ti。优化了仪器测定参数,选择背景低、信背比高、干扰小的谱线为待测元素的谱线,利用基体匹配来消除表面张力、粘度、密度和盐分等造成雾化器提升效率的差异而引起的物理干扰,通过选择波长、改变称样量对样品浓度进行适当的控制来克服光谱干扰。确定了方法的分析范围,各元素检出限范围为0.000 1%~0.036%,线性方程的相关系数均大于0.998 0。方法用于测定有证参考物质及其他石灰石中Fe,Al,Ca,Mg,K,Na,Ti,RSD为0.26%~0.59%,测定结果与认定值、推荐值的分析结果吻合较好。

Through using the phosphoric acid and nitric acid as digestive reagent and four work-step microve digestion to decompose the sample, a method for the determination of Fe,Al,Ca,Mg,K,Na and Ti in limestone was established by inductively coupled plasma atomic emission spectrometry（ICP- AES）. The measuring parameters of instrument were optimized, the spectral lines with low back- ground, high signal ratio and small interference were chosen as the analytical spetral lines of the deter- minated elements. Matrix matching was used to eliminate the physical interference from the difference of lifting efficency of atomizer, which was caused by surface tension, viscosity, density and salt, etc. The spectral interference was overcome by selecting wavelength and changing sample weight to control proper concentration of sample. The analytical scope of the method was confirmed. The detection lim- it range was from 0. 000 1 ~ to 0. 036~, and all correlation coefficients of linear equations were above 0. 998 0. The method has been applied to determination of Fe, Al, Ca, Mg, K, Na and Ti in the certified reference materials and other limestone samples with RSD of 0.26%-0. 59%. The measured resuits are accordant with the certified and recommended values.