Analyte Response in Laser Ablation Inductively Coupled Plasma Mass Spectrometry

• Published in: Journal of the American Society for Mass Spectrometry Vol. 17; no. 5; pp. 641 - 651
• Main Authors: Wang, Zhongke, Hattendorf, Bodo, Günther, Detlef
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2006; Elsevier Science; Springer Nature B.V
• Subjects: ABLATION; AEROSOLS; Atomizing; Carrier gases; Chemical properties; DIFFUSION; Diffusion rate; EFFICIENCY; ENERGY TRANSFER; EVAPORATION; Exact sciences and technology; FRACTIONATION; GAS FLOW; Gases; Helium; ICP MASS SPECTROSCOPY; Inductively coupled plasma mass spectrometry; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Ion optics; Kinetic energy; Laser ablation; Lasers; MASS SPECTROMETERS; Mass spectrometers and related techniques; Mass spectrometry; Parameter sensitivity; Particle size distribution; Physics; PLASMA; SENSITIVITY; Sensitivity analysis; SPACE CHARGE; Vaporization; Sensitivity; Laser ablation technique; Instrumental response; ICP mass spectroscopy; Vaporization
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2006.01.005

The dependence of analyte sensitivity and vaporization efficiency on the operating parameters of an inductively coupled plasma mass spectrometer (ICPMS) was investigated for a wide range of elements in aerosols, produced by laser ablation of silicate glass. The ion signals were recorded for different carrier gas flow rates at different plasma power for two different laser ablation systems and carrier gases. Differences in atomization efficiency and analyte sensitivity are significant for the two gases and the particle size distribution of the aerosol. Vaporization of the aerosol is enhanced when helium is used, which is attributed to a better energy-transfer from the plasma to the central channel of the ICP and a higher diffusion rate of the vaporized material. This minimizes elemental fractionation caused by sequential evaporation and reduces diffusion losses in the ICP. The sensitivity change with carrier gas flow variation is dependent on m/z of the analyte ion and the chemical properties of the element. Elements with high vaporization temperatures reach a maximum at lower gas flow rates than easily vaporized elements. The sensitivity change is furthermore dependent on m/z of the analyte ion, due to the mass dependence of the ion kinetic energies. The mass response curve of the ICPMS is thus not only a result of space charge effects in the ion optics but is also affected by radial diffusion of analyte ions and the mismatch between their kinetic energy after expansion in the vacuum interface and the ion optic settings.