Effect of Sampling Depth on the Analyte Response in Laser Ablation Inductively Coupled Plasma Mass Spectrometry

摘要

The dependence of analyte sensitivity and vaporization efficiency on the sampling depth of an inductively coupled plasma mass spectrometer (ICPMS) was investigated for a wide range of ele- ments in aerosols, produced by laser ablation of silicate glass. The ion signals were recorded 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. Vaporiza- tion 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 mate- rial. Stable signal is achieved at smaller particle size distribution in laser-generated aerosol. The sensitivity change with sampling depth variation is dependent on m/z of the analyte ion and the chemical properties of the element. Elements with high vaporization temperatures need longer residence time to be atomized and ionized in ICP plasma and reach a maximum at increasing sam- pling depth than easily vaporized elements, especially for bigger particle size distributions generated by 266 nm laser in Argon.