KED碰撞模式-电感耦合等离子体质谱(ICP-MS)法测定多种煤中磷

Determination of Phosphorus in Various Coal by Inductively Coupled Plasma Mass Spectrometry with Kinetic Energy Discrimination Collision Mode

为快速准确测定不同煤质样品中磷元素的含量,建立了混合酸消解-KED碰撞模式-电感耦合等离子体质谱(ICP-MS)法测定多种煤中磷的方法。考察了样品灰化温度、灰化时间、消解试剂等对磷元素测定结果的影响,试样经箱式电阻炉在815℃灼烧1.5 h灰化后,采用盐酸-硝酸-氢氟酸-高氯酸体系进行消解,用王水提取,以磷元素特定质量数31(质荷比,m/z)定性,以磷元素和^(103)Rh内标元素质谱信号的强度比值与磷元素的浓度成正比进行定量分析,向碰撞反应池中通入碰撞混合气,与相同质量数的多原子离子物质发生有效碰撞使其质荷比发生变化,从而降低氧化物产率、消除双电荷产生的质谱干扰,准确测定试样中磷的含量。磷标准溶液浓度在0.5~50μg/mL范围内呈现良好的线性关系,磷校准曲线方程为y=3985 x-226.23,相关系数(R^(2))=0.9998。方法检出限为0.96μg/g。选用17种不同种类国家一级标准物质进行验证,测定值与认定基本一致,相对标准偏差(RSD)均≤9.6%(n=12),相对误差(RE)均≤4.6%,各种标准物质磷元素测定t值均小于2.20(t_(0.05,11)值),测定结果与标准物质认定值具有较好的一致性,且无显著性差异,方法可用于不同煤质样品中磷元素的测定。

In order to quickly and accurately determine the content of phosphorus in different coal samples,a method for the determination of phosphorus in various coals by mixed acid digestion KED collision mode inductively coupled plasma mass spectrometry(ICP-MS)was established.The effects of sample ash temperature,time and digestion reagent on the determination results of phosphorus were investigated after ashing in a box resistance furnace at 815℃for 1.5 h,acidolysis is carried out with hydrochloric acid nitric acid hydrofluoric acid perchloric acid system,aqua regia extraction,qualitative analysis is carried out with the specific mass number of phosphorus 31(mass charge ratio,m/z),quantitative analysis is carried out with the intensity ratio of mass spectrum signals of phosphorus and ^(103)Rh internal standard elements in direct proportion to the concentration of phosphorus,and collision mixture gas is introduced into the collision reaction tank,the effective collision with polyatomic ionic substances with the same mass number changes the mass charge ratio,reduces the oxide yield,eliminates the mass spectrum interference caused by double charge,and accurately determines the content of phosphorus in the sample.The concentration of phosphorus standard solution showed a good linear relationship in the range of 0.5—50μg/mL.The phosphorus calibration curve equation is y=3985 x-226.23,and the correlation coefficient(R^(2))=0.9998.The detection limit was 0.96μg/g.Different kinds of national first-class reference materials are selected for verification.The measured values are basically consistent with the certified values,the relative standard deviation(RSD)is≤9.6%(n=12),the relative error(RE)is≤4.6%,and the measured t values of phosphorus in various reference materials are less than 2.20(t_(0.05,11)).The measured results of this method are in good agreement with the certified values of reference materials,and there is no significant difference.The method can be used for the determination of phosphorus in different coal samples.