A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Origins of Polyatomic Ions in Laser Ablation - Inductively Coupled Plasma – Mass Spectrometry: An Examination of Metal Oxide Ions & Effects of Nitrogen and Helium in the Aerosol Gas Flow
25 February 2012, 21:53:31
Publication year: 2012
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 25 February 2012
Travis M. Witte, R.S. Houk
Differences in the origins of polyatomic ions in wet plasma conditions, as exist in solution inductively coupled plasma-mass spectrometry (ICP-MS), versus dry plasma conditions, found in laser ablation (LA)-ICP-MS, are investigated. Silicate and metal samples are ablated and gas kinetic temperature (Tgas) is measured to establish the origins of metal oxide (MO) ions. MOion abundances observed from both the ablation of silicate samples and metallic samples are found to correspond to formation of the polyatomic ion in the ICP. The same strategy is applied to oxide ratios measured when additional gases (N2and He) are introduced into the aerosol gas flow. N2is found to decrease the MO/Msignal ratio by maximizing atomic sensitivity at lower total gas loads. The addition of He reduces polyatomic ions throughout the plasma. Use of both N2and He produces the lowest MO/Msignal ratio and highest Tgasvalues at the position sampled in the ICP. By gaining a better understanding of the origin of polyatomic ions in LA-ICP-MS and their behavior in mixed gas plasmas, perhaps strategies can be developed to minimize polyatomic interferences in the mass spectrum.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 25 February 2012
Travis M. Witte, R.S. Houk
Differences in the origins of polyatomic ions in wet plasma conditions, as exist in solution inductively coupled plasma-mass spectrometry (ICP-MS), versus dry plasma conditions, found in laser ablation (LA)-ICP-MS, are investigated. Silicate and metal samples are ablated and gas kinetic temperature (Tgas) is measured to establish the origins of metal oxide (MO) ions. MOion abundances observed from both the ablation of silicate samples and metallic samples are found to correspond to formation of the polyatomic ion in the ICP. The same strategy is applied to oxide ratios measured when additional gases (N2and He) are introduced into the aerosol gas flow. N2is found to decrease the MO/Msignal ratio by maximizing atomic sensitivity at lower total gas loads. The addition of He reduces polyatomic ions throughout the plasma. Use of both N2and He produces the lowest MO/Msignal ratio and highest Tgasvalues at the position sampled in the ICP. By gaining a better understanding of the origin of polyatomic ions in LA-ICP-MS and their behavior in mixed gas plasmas, perhaps strategies can be developed to minimize polyatomic interferences in the mass spectrum.
Highlights
► MOions are the most abundant polyatomic ions from the sample in LA-ICP-MS. ► The MO/Msignal ratios correspond to a Tgasvalue of ~ 5500 K. ► This Tgasvalue indicates these MOions are not formed during ion extraction. ► N2and/or He in the aerosol gas reduces the abundance of MOions during LA.Quantification of the fluorine containing drug 5-fluorouracil in cancer cells by GaF molecular absorption via high-resolution continuum source molecular absorption spectrometry
25 February 2012, 21:53:31
Publication year: 2012
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 24 February 2012
Magnus Krüger, Mao-Dong Huang, Helmut Becker-Roß, Stefan Florek, Ingo Ott, ...
The development of high-resolution continuum source molecular absorption spectrometry made the quantification of fluorine feasible by measuring the molecular absorption as gallium monofluoride (GaF). Using this new technique, we developed on the example of 5-fluorouracil (5-FU) a graphite furnace method to quantify fluorine in organic molecules. The effect of 5-FU on the generation of the diatomic GaF molecule was investigated. The experimental conditions such as gallium nitrate amount, temperature program, interfering anions (represented as corresponding acids) and calibration for the determination of 5-FU in standard solution and in cellular matrix samples were investigated and optimized. The sample matrix showed no effect on the sensitivity of GaF molecular absorption. A simple calibration curve using an inorganic sodium fluoride solution can conveniently be used for the calibration. The described method is sensitive and the achievable limit of detection is 0.23 ng of 5-FU. In order to establish the concept of “fluorine as a probe in medicinal chemistry” an exemplary application was selected, in which the developed method was successfully demonstrated by performing cellular uptake studies of the 5-FU in human colon carcinoma cells.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 24 February 2012
Magnus Krüger, Mao-Dong Huang, Helmut Becker-Roß, Stefan Florek, Ingo Ott, ...
The development of high-resolution continuum source molecular absorption spectrometry made the quantification of fluorine feasible by measuring the molecular absorption as gallium monofluoride (GaF). Using this new technique, we developed on the example of 5-fluorouracil (5-FU) a graphite furnace method to quantify fluorine in organic molecules. The effect of 5-FU on the generation of the diatomic GaF molecule was investigated. The experimental conditions such as gallium nitrate amount, temperature program, interfering anions (represented as corresponding acids) and calibration for the determination of 5-FU in standard solution and in cellular matrix samples were investigated and optimized. The sample matrix showed no effect on the sensitivity of GaF molecular absorption. A simple calibration curve using an inorganic sodium fluoride solution can conveniently be used for the calibration. The described method is sensitive and the achievable limit of detection is 0.23 ng of 5-FU. In order to establish the concept of “fluorine as a probe in medicinal chemistry” an exemplary application was selected, in which the developed method was successfully demonstrated by performing cellular uptake studies of the 5-FU in human colon carcinoma cells.
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