System optimization for determination of cobalt in biological samples by ICP-OES using photochemical vapor generation

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1039/C6JA00069J
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Name affiliation
  1. National Research Council of Canada. Measurement Science and Standards
FormatText, Article
Journal titleJournal of Analytical Atomic Spectrometry
ISSN0267-9477
1364-5544
Volume31
Issue8
Pages1590–1604
Abstract
An optimized photochemical vapor generation (PVG) approach for efficient synthesis of volatile cobalt species is described. Solutions containing Co(II) in a pH 3.3 medium of 50% formic acid were exposed to a source of deep UV (254 and 185 nm) radiation generated within a 19 W flow-through low pressure mercury discharge lamp. Following efficient phase separation, the analyte was transported to an ICP-OES system for detection at the 238.892 nm emission line of Co I. Several variables were investigated, including the type of UV lamp and gas–liquid separator, identity and concentration of the low molecular weight organic acid, solution pH, sample flow rate and exposure time to the UV irradiation as well as transport gas flow and mode of introduction of sample (continuous or segmented) to the ICP. In continuous mode, an optimum generation efficiency of 42 ± 2% was achieved with an irradiation time of 10 s, providing a 27-fold improvement in sensitivity compared to pneumatic nebulization and a limit of detection of 0.4 μg L−1 with a precision of 3% at 100 μg L−1. Direct analysis of acid digested biological tissues (NRC TORT-2 and TORT-3) was hampered by strong matrix interferences from the presence of nitrate and other ions which could be circumvented by longer irradiation time and sufficient dilution such that accurate analysis of real samples by the method of additions could be achieved while maintaining high generation efficiency.
Publication date
PublisherRoyal Society of Chemistry
LanguageEnglish
Peer reviewedYes
NPARC number23002548
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