Abstract：Inductively coupled plasma mass spectrometry is one of the powerful analytical methods for trace elements due to its high sensitivity and low detection limit. However, the simultaneous determination of major elements and trace elements is performed in many applications, which requires a wide linear dynamic range. Based on the dual-mode detector for inductively coupled plasma mass spectrometer (ICP-MS), a correction method for detection mode of this type of detector, namely Pulse Analog (PA) correction method, was investigated. Firstly, according to the dynamic range desired, the negative high voltage and positive high voltage of the detector was determined. The appropriate threshold voltage for this detector was obtained to ensure that the test signal was collected, and the noise signal was removed (the counting value at 220 u was less than 0.1 cps). Then the flow rate of helium (He) gas for collision reaction cell was determined, so that the counting value of test element at the concentration of 0.1 ng/L was less than 10 cps. Finally, the signal testing was conducted to determine the overlapping elements and their test data. The Pulse-Analog correction coefficient (abbreviated as PA coefficient) was calculated. Cubic polynomial fitting was performed to obtain the PA coefficients of elements in whole mass range. The fitting methods of spline interpolation and cubic polynomial were compared. The results showed that the fitting data by cubic polynomial were closer to the trend of original data within the whole mass range of 2-250 u. The proposed calibration method was validated using low, medium, and high mass number elements of Be, Cd, and U (0.1 ng/L-100 mg/L) with a linear dynamic range of 9 orders of magnitude. The results showed that the determination coefficients of calibration curves were all 1.000, and the determination coefficients of calibration curves were all higher than 0.999 5 under logarithmic coordinates of the test data. The superalloy certified reference material of GBW01636, which contained Cu, Ga, As, and Bi with content span in four orders of magnitude, was selected for verification, and the results showed that the test values were basically consistent with the certified values. The proposed correction method could achieve the simultaneous determination of major and trace elements with a linear dynamic range of up to 9 orders of magnitude, which could meet the test requirements of wide concentration range in certain applications.
李凯, 王雷, 王海舟, 钊金辉, 王小龙, 方哲. 基于电感耦合等离子体质谱仪开发的检测器检测模式校正方法[J]. 冶金分析, 2024, 44(6): 1-10.
LI Kai, WANG Lei, WANG Haizhou, ZHAO Jinhui, WANG Xiaolong, FANG Zhe. A detector detection mode correction method developed based on inductively coupled plasma mass spectrometer. , 2024, 44(6): 1-10.
[1] Smoluch M,Grasso G,Suder P.Mass spectrometry:An applied approach[M].New Jersey:John Wiley & Sons,Inc.,2019. [2] Wilschefski S C,Baxter M R.Inductively coupled plasma mass spectrometry:introduction to analytical aspects[J].The Clinical Biochemist Reviews,2019,40(3):115-133. [3] Simon M.ICP mass spectrometry handbook[M].Oxford:Blackwell Publishing Ltd.,2005. [4] Hunter K,Stresau D.Ion counting beyond 10 ghz using a new detector and conventional electronics[R].Ermington:ETP Electron Multipliers,2001. [5] Hutton R C,Eaton A N,Gosland R M.Application of a dual-mode detection system for ICP-MS.Part I:Determination of majors,minors,and traces in geostandards[J].Applied Spectroscopy,1990,44(2):238-242. [6] Schilling G D,Andrade F J,Roger P B,et al.Continuous simultaneous detection in mass spectrometry[J].Analytical Chemistry,2007,79(20):7662-7668. [7] Hamester M,Toms A,Chemnitzer R.High sensitivity ICP-MS:Overcome the problem of complex samples[R].Berlin:Bruker Chemical Analysis,2013. [8] Sharad M.Mass spectrometry:Detector review[J].Chemical and Biomolecular Engineering,2018,3(4):51-58. [9] Yamamoto K,Asanuma H,Takahashi H,et al.In situ isotopic analysis of uranium using a new data acquisition protocol for 1013 ohm faraday amplifiers[J].Journal of Analytical Atomic Spectrometry,2021,36:668-675. [10] 中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.GB/T 34826—2017 四极杆电感耦合等离子体质谱仪性能的测定方法[S].北京:中国标准出版社,2017.
