ICPES analyses using full image spectra and astronomical data fitting algorithms to provide diagnostic and result information
- Westinghouse Savannah River Company, Aiken, SC (United States)
- Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemistry and Biochemsitry
ICP emission analyses are prone to errors due to changes in power level, nebulization rate, plasma temperature, and sample matrix. As a result, accurate analyses of complex samples often require frequent bracketing with matrix matched standards. Information needed to track and correct the matrix errors is contained in the emission spectrum. But most commercial software packages use only the analyte line emission to determine concentrations. Changes in plasma temperature and the nebulization rate are reflected by changes in the hydrogen line widths, the oxygen emission, and neutral ion line ratios. Argon and off-line emissions provide a measure to correct the power level and the background scattering occurring in the polychromator. The authors` studies indicated that changes in the intensity of the Ar 404.4 nm line readily flag most matrix and plasma condition modifications. Carbon lines can be used to monitor the impact of organics on the analyses and calcium and argon lines can be used to correct for spectral drift and alignment. Spectra of contaminated groundwater and simulated defense waste glasses were obtained using a Thermo Jarrell Ash ICP that has an echelle CID detector system covering the 190-850 nm range. The echelle images were translated to the FITS data format, which astronomers recommend for data storage. Data reduction packages such as those in the ESO-MIDAS/ECHELLE and DAOPHOT programs were tried with limited success. The radial point spread function was evaluated as a possible improved peak intensity measurement instead of the common pixel averaging approach used in the commercial ICP software. Several algorithms were evaluated to align and automatically scale the background and reference spectra. A new data reduction approach that utilizes standard reference images, successive subtractions, and residual analyses has been evaluated to correct for matrix effects.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035; AC09-96SR18500
- OSTI ID:
- 562526
- Report Number(s):
- WSRC-MS-97-0078; CONF-970333-; ON: DE98050004; TRN: 98:000436
- Resource Relation:
- Conference: PITTCON `97: 48. Pittsburgh conference on analytical chemistry and applied spectroscopy, Atlanta, GA (United States), 17-21 Mar 1997; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
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