直接进样-电感耦合等离子体质谱法测定MOS级吡啶试剂中20种杂质元素的含量

Determination of 20 Impurity Elements in MOS Grade Pyridine Reagent by Inductively Coupled Plasma Mass Spectrometry with Direct Sampling

鉴于繁琐的消解前处理会对超纯试剂引入污染,而直接进样法既能控制污染来源,又可避免易挥发元素的损失,提出了题示方法研究。在待测MOS级吡啶试剂中加入6个浓度水平的多元素混合标准溶液,采用电感耦合等离子体质谱法测定,分别以20种杂质元素(锂、铍、硼、钾、钙、钒、铬、铁、钴、镍、镓、锗、砷、钼、镉、铟、锑、钡、铅、铋)的加标量为横坐标,对应的响应值与内标响应值比值为纵坐标绘制工作曲线。通过优化氧气流量、雾化气流量、采样深度等参数消除有机质干扰,采用碰撞模式(用于分析锂、铍、硼、钙、钒、钴、镍、镓、锗、砷、钼、镉、铟、锑、钡、铅、铋)或反应模式(用于分析钾、铬、铁)消除质谱干扰,以标准加入法和内标法定量校正基体效应。结果表明:优化的氧气流量为30 mL·min^(-1),雾化气流量为0.55 L·min^(-1),采样深度为4.5 mm;反应模式下,当氢气流量为1.40 mL·min^(-1)时,钾、铬、铁的背景等效浓度较低;20种杂质元素的检出限为0.001~0.383μg·L^(-1);对加标样品重复测定7次,测定值的相对标准偏差均小于6.0%,加标回收率为91.0%~127%。

In view of the complicated digestion pretreatment would contaminate the ultra-pure reagent,and direct injection method could not only control the source of contamination,but also avoid the loss of volatile elements,the method mentioned by this article was proposed.The multi-element mixed standard solutions with 6 concentration levels were added into the MOS grade pyridine reagent to be tested,and the inductively coupled plasma mass spectrometry was used for determination.The addition amounts of 20 impurity elements(lithium,beryllium,boron,potassium,calcium,vanadium,chromium,iron,cobalt,nickel,gallium,germanium,arsenic,molybdenum,cadmium,indium,antimony,barium,lead and bismuth) were used as the horizontal coordinates,and the response value ratios of the corresponding element to the internal standard were used as the ordinates to draw the working curves.The interference of organic matter was eliminated by optimizing the flow rate of oxygen,flow rate of atomized gas and sampling depth,and the interference of mass spectrum was eliminated by collision mode(for lithium,beryllium,boron,calcium,vanadium,cobalt,nickel,gallium,germanium,arsenic,molybdenum,cadmium,indium,antimony,barium,lead and bismuth) or reaction mode(for potassium,chromium and iron),and the matrix effect was corrected with standard addition method and internal standard method for quantitative analysis.It was shown that the optimized flow rate of oxygen was 30 mL·min^(-1),flow rate of atomized gas was 0.55 L·min^(-1),and sampling depth was 4.5 mm.In the reaction mode,when the flow rate of hydrogen was 1.40 mL·min^(-1),the values of background equivalent concentration of potassium,chromium and iron were low.The detection limits of 20 impurity elements were in the range of 0.001-0.383 μg·L^(-1).The spiked sample was determined 7 times,and RSDs of the determined values were less than 6.0%,with recoveries ranged from 91.0% to 127%.