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Measurement of elemental concentration of aerosols using spark emission spectroscopy.

Authors
Diwakar-P; Kulkarni-P
Source
J Anal At Spectrom 2012 Jul; 27(7):1101-1109
NIOSHTIC No.
20041004
Abstract
A coaxial microelectrode system has been used to collect and analyse the elemental composition of aerosol particles in near real-time using spark emission spectroscopy. The technique involves focused electrostatic deposition of charged aerosol particles onto the flat tip of a microelectrode, followed by introduction of spark discharge. A pulsed spark discharge was generated across the electrodes with input energy ranging from 50 to 300 mJ per pulse, resulting in the formation of controlled pulsed plasma. The particulate matter on the cathode tip is ablated and atomized by the spark plasma, resulting in atomic emissions which are subsequently recorded using a broadband optical spectrometer for element identification and quantification. The plasma characteristics were found to be very consistent and reproducible even after several thousands of spark discharges using the same electrode system. The spark plasma was characterized by measuring the excitation temperature (7000 to 10000 K), electron density (1016 cm-3), and evolution of spectral responses as a function of time. The system was calibrated using particles containing Pb, Si, Na and Cr. Absolute mass detection limits in the range 11 pg to 1.75 ng were obtained. Repeatability of spectral measurements varied from 2 to 15%. The technique offers key advantages over similar microplasma-based techniques such as laser-induced breakdown spectroscopy, as: (i) it does not require any laser beam optics and eliminates any need for beam alignment, (ii) pulse energy from dc power supply in SIBS system can be much higher compared to that from laser source of the same physical size, and (iii) it is quite conducive to compact, field-portable instrumentation.
Keywords
Aerosols; Aerosol-particles; Analytical-processes; Analytical-instruments; Spectrographic-analysis; Particulates; Particulate-dust; Aerosol-particles
CODEN
JASPE2
Publication Date
20120701
Document Type
Journal Article
Fiscal Year
2012
NTIS Accession No.
NTIS Price
Identifying No.
B07092012
Issue of Publication
7
ISSN
0267-9477
NIOSH Division
DART
Priority Area
Manufacturing; Services: Public Safety
Source Name
Journal of Analytical Atomic Spectrometry
State
OH
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