Change search
ReferencesLink to record
Permanent link

Direct link
Radial ICP characteristics for ICP-AES using direct injection or microconcentric nebulisation
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Delft University of Technology, Faculty of Applied Sciences, Julianalaan, The Netherlands.
2005 (English)In: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 20, no 7, 645-651 p.Article in journal (Refereed) Published
Abstract [en]

Radial analyte signal intensities, fundamental plasma parameters, and non-spectral interference effects were characterized for inductively coupled plasma atomic emission spectrometry (ICP-AES) using a direct injection nebuliser (Vulkan DIN) or a microconcentric nebuliser (MCN) coupled to a cyclonic spray chamber for sample introduction. Radial analyte signal intensity profiles for atomic and ionic lines with energy sum (Esum) between 1.85 and 15.41 eV were used. When using the MCN system, for all lines the signal intensity profiles were parabolic with maxima at the axial centre of the plasma. For the Vulkan DIN, the shapes of the profiles were dependent on their Esum showing minimum intensities at the axial centre of the plasma for lines with high Esum values. The ionisation temperature, electron number density and magnesium ion-atom line intensity ratio determined indicated that ionisation and excitation capabilities were deteriorated at the centre of the plasma when using the Vulkan DIN compared with the MCN. This was found to be not simply a result of high aerosol load when using the Vulkan DIN, but because of poor plasma–aerosol interaction, possibly caused by the confined distribution of aerosol in the plasma and high nebuliser gas velocity. Indeed, for the Vulkan DIN, electron number density and ionisation temperature increased with liquid flow rate, which could be explained by plasma shrinkage, or the thermal pinch effect, which increased the aerosol–plasma interaction at increased liquid flow rates. As a consequence, when increasing the liquid flow rate in the range 20–90 µL min–1: (i) analyte sensitivity increased linearly; (ii) the plasma became unstable; (iii) the magnitude of matrix effects remained almost unaffected. These results are partly in contrast to observations made with other types of direct injection nebulisers and ICP instruments.


Place, publisher, year, edition, pages
London: Royal Society of Chemistry , 2005. Vol. 20, no 7, 645-651 p.
URN: urn:nbn:se:umu:diva-4910DOI: 10.1039/b416594bOAI: diva2:144190
Available from: 2006-01-12 Created: 2006-01-12 Last updated: 2011-03-17Bibliographically approved
In thesis
1. Fundamental Studies on Direct Injection Nebulisers for Sample Introduction in ICP Spectrometry: Aerosol Properties, ICP Characteristics and Analytical Performance
Open this publication in new window or tab >>Fundamental Studies on Direct Injection Nebulisers for Sample Introduction in ICP Spectrometry: Aerosol Properties, ICP Characteristics and Analytical Performance
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The performance of different types of nebulisers: Vulkan direct injection nebuliser (Vulkan DIN), direct injection high efficiency nebuliser (DIHEN), microconcentric nebuliser coupled to cyclonic or double pass spray chamber (MCN-C or MCN-DP, respectively) was investigated and compared when used for sample introduction to ICP-MS or ICP-OES. With ICP-OES, in axial viewing mode, intensity distributions across the radius of the plasma (radial intensity profiles) were determined for different spectral lines with Esum 1.85-15.41 eV to determine fundamental plasma properties for various matrices using Vulkan DIN and MCN-C. The results showed that with the MCN-C the ionisation temperature (Tion) was about the same across the measured region of the plasma (±3.0 mm) whereas with the Vulkan DIN the Tion was significantly lower in the centre of the plasma. A large deviation from local thermodynamic equilibrium, as well as deteriorated stability, was observed for the plasma when using the Vulkan DIN.

With ICP-MS noise power spectra (NPS) were generated to identify sources of noise. NPS showed that the magnitude of white noise for the tested sample introduction systems decreased in the following order: Vulkan DIN > DIHEN > MCN-C > MCN-DP. This order follows the decrease of mean droplet size and span of the size distribution, indicating that the white noise is caused by spatial and temporal non-uniform desolvation and ionisation. Another source of noise arose from the peristaltic pump and the magnitude of pump interference noise decreased in the following order: DIHEN > MCN-C/DP > Vulkan DIN. Mains power interference noise and 1/f noise were lower for the direct injection nebulisers compared to the spray chamber systems. The contribution or effects of these noise components on relative standard deviations of steady-state ion-count rate and isotope ratio measurements is discussed in this thesis.

Aerosols generated by the Vulkan DIN and the DIHEN were also directly characterised using Particle Dynamic Analysis. The Vulkan DIN produced particles with a mean diameter of ~30 µm and a size distribution between 2-80 µm. With the DIHEN the corresponding values were ~11 µm and 1-40 µm, respectively, with a few particles at 55-78 µm. The mean velocity of particles from the Vulkan DIN was ~10 m s-1 and from the DIHEN ~18 m s-1. The lower velocity allows longer residence time counteracting the effects of the larger droplet size.

Place, publisher, year, edition, pages
Umeå: Kemi, 2006. 40 p.
ICP, ICP-MS, ICP-OES, sample introduction, DIHEN, Vulkan DIN, non-spectral interferences, noise power spectra, analytical precision, plasma diagnostic parameters, particle dynamic analysis (PDA)
National Category
Analytical Chemistry
urn:nbn:se:umu:diva-671 (URN)91-7264-012-X (ISBN)
Public defence
2006-02-03, N350, Naturvetarhuset, Umeå Universitet, Umeå, 10:00
Available from: 2006-01-12 Created: 2006-01-12Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Björn, ErikFrech, Wolfgang
By organisation
Department of Chemistry
In the same journal
Journal of Analytical Atomic Spectrometry

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 108 hits
ReferencesLink to record
Permanent link

Direct link