微波消解-高分辨电感耦合等离子体质谱(HR-ICP-MS)法测定煤炭中35种痕量金属元素

高分辨电感耦合等离子体质谱可以区分干扰元素和目标元素微弱的质量数差别,能解决大多数多原子、氧化物干扰问题,在煤炭痕量元素分析领域受到关注,但煤炭样品中痕量金属元素尤其是稀土元素受到的质谱干扰挑战未被系统地报道。采用HNO₃-HF混酸微波消解煤炭样品,优化了消解时间、赶酸、复溶等前处理条件,研究了煤炭中V、Cr、Mn、Co、Ni、Cu、Ga、Ge、As、Rb、Sr、Y、Nb、Mo、Cd、Sn、Sb、Cs、Ba、La、Ce、Pr、Nd、Sm、Eu、Dy、Gd、Tb、Ho、Er、Lu、Hf、Tl、Pb、Th共35种痕量金属元素在低、中、高分辨率下的质谱干扰,采用高分辨率模式测定Ge、Nd、Eu、Gd、Ho、Er、Lu,采用中分辨率模式测定Ga,采用低分辨率模式测定其余元素,建立了高分辨电感耦合等离子体质谱法测定煤炭中35种痕量金属元素的方法。在优化的实验条件下,各元素标准曲线线性相关系数均在0.9999以上,检出限为0.001~0.082μg/g。选择煤炭标准样品(SARM 20)进行方法验证,测定结果的相对标准偏差为0.27%~6.3%,测定值与标准值基本一致,标准样品中无认证值的元素进行加标回收实验,加标回收率为85.8%~117%。选取俄罗斯其他烟煤、澳大利亚其他烟煤、蒙古炼焦煤、印度尼西亚其他烟煤4个代表性样品进行测试,分析了不同产地煤炭的痕量金属元素含量差异。Mn、Ba、Sr以及稀土元素的含量在4种煤炭中存在差异,可支撑煤炭原产地分析。

Determination of 35 Trace Metal Elements in Coal by High Resolution Inductively Coupled Plasma Mass Spectrometry with Microwave Digestion

The weak mass number difference of interference elements and target elements can be distinguished by high resolution coupled plasma mass spectrometry which can solve the mass spectrometry of polyatoms and oxides.It has been focused on trace element analysis in coal,but the application is still not mature enough.The challenge of mass spectrometry interference in determination of trace metal elements,especially rare earth elements in coal has not been systematically reported.HNO₃-HF mixed acid was used to digest coal samples,pretreatment conditions such as digestion time,evaporation acid and resolution were optimized.The mass spectrometry interference of V,Cr,Mn,Co,Ni,Cu,Ga,Ge,As,Rb,Sr,Y,Nb,Mo,Cd,Sn,Sb,Cs,Ba,La,Ce,Pr,Nd,Sm,Eu,Dy,Gd,Tb,Ho,Er,Lu,Hf,Tl,Pb,Th total 35 trace metal elements at low,middle and high resolution was studied.Ge,Nd,Eu,Gd,Ho,Er,Lu were determined in high resolution pattern,Ga was determined in mid-resolution pattern,the remaining elements were determined in low resolution pattern.A method for measuring 35 trace metal elements in coal with high resolution inductively coupled plasma mass spectrometry was established.Under the optimized experimental conditions,the linear correlation coefficient of each element standard curve is greater than 0.9999,and the detection limit is 0.001—0.082μg/g.Coal standard sample(SARM 20)was selected for method verification,and elements with no certified value in the standard sample were basically matched with the standard experiment,the relative standard deviation of determination results are 0.27%—6.3%and the standard recoveries are 85.8%—117%.Four representative samples of other bituminous coal from Russian,other bituminous coal from Australian,coking coal from Mongolian,and other bituminous coal from Indonesia were selected for testing,and the differences of trace metal element contents in coal from different producing areas were analyzed.The centents of Mn,Ba,Sr and rare earth elements are different in four coals,which can support the analysis of coal origin.