FUNDAMENTAL AND APPLIED MEASUREMENTS IN ICP-MS
type: CreativeWork
description: Fundamental and applied aspects of ICP-MS have been investigated to gain an increased understanding of the technique and improve on its analytical capabilities. Dissociation temperatures of polyatomic ions were calculated using a double-focusing sector instrument, to obtain more reliable mass spectral data with controlled vapour introduction via a Dreschel bottle to allow accurate calculation of the ingredients in the plasma. The equilibrium temperature for the plasma, operated at 1280 W calculated using CO*, and as the thermometric probes, was c.a. 5800 - 7400 K, while using ArO* and ArC* as the thermometric probes the temperature calculated was c.a 2000 - 7000 K. Calculated dissociation temperatures were used to elucidate the site of formation of these ions. Results confirmed that strongly bound ions such as CO* and C2* were formed in the plasma whereas weakly bound ions such as ArO* and ArC* were formed in the interface region due to gross deviation of the calculated temperatures from those expected for a system in thermal equilibrium. The use of helium gas in a hexapole collision cell Attenuated the signals of ArH* Ar* ArO*, Arc*, ArCl* and Ara* allowing improved determination of ^^K*, *'Ca*, ^^e* ^^Cr*, ''As* and ^°Se*in standard solutions. The use of the hexapole collision cell also resulted in an enhancement of analyte signals due to the thermalisation of the ion beam. The ion kinetic energy of ions sampled from the plasma and those sampled from the skimmer cone were determined using a modified lens stack to assess the significance for memory effects of material deposited on the skimmer cone. The most probable kinetic energy of Be* ions sampled from the skimmer cone was found to be 2A eV, which was considerably lower than the most probable kinetic energy of Be* ions sampled from the plasma, which was found to be 9.5 eV. The low kinetic energy of the ions deposited on the skimmer cone means they will only contribute to the analytical signal under certain instr…
abstract: Fundamental and applied aspects of ICP-MS have been investigated to gain an increased understanding of the technique and improve on its analytical capabilities. Dissociation temperatures of polyatomic ions were calculated using a double-focusing sector instrument, to obtain more reliable mass spectral data with controlled vapour introduction via a Dreschel bottle to allow accurate calculation of the ingredients in the plasma. The equilibrium temperature for the plasma, operated at 1280 W calculated using CO*, and as the thermometric probes, was c.a. 5800 - 7400 K, while using ArO* and ArC* as the thermometric probes the temperature calculated was c.a 2000 - 7000 K. Calculated dissociation temperatures were used to elucidate the site of formation of these ions. Results confirmed that strongly bound ions such as CO* and C2* were formed in the plasma whereas weakly bound ions such as ArO* and ArC* were formed in the interface region due to gross deviation of the calculated temperatures from those expected for a system in thermal equilibrium. The use of helium gas in a hexapole collision cell Attenuated the signals of ArH* Ar* ArO*, Arc*, ArCl* and Ara* allowing improved determination of ^^K*, *'Ca*, ^^e* ^^Cr*, ''As* and ^°Se*in standard solutions. The use of the hexapole collision cell also resulted in an enhancement of analyte signals due to the thermalisation of the ion beam. The ion kinetic energy of ions sampled from the plasma and those sampled from the skimmer cone were determined using a modified lens stack to assess the significance for memory effects of material deposited on the skimmer cone. The most probable kinetic energy of Be* ions sampled from the skimmer cone was found to be 2A eV, which was considerably lower than the most probable kinetic energy of Be* ions sampled from the plasma, which was found to be 9.5 eV. The low kinetic energy of the ions deposited on the skimmer cone means they will only contribute to the analytical signal under certain instr…
author: CARTER, JULIAN ROBERT
language: eng
date published: 2002-01-01T08:00:00Z
date modified: 2026-07-24T03:49:35Z
provider: University of Plymouth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Plymouth