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Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.
Wang-J; Ashley-K; Marlow-D; England-EC; Carlton-G
Anal Chem 1999 Mar; 71(5):1027-1032
A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromiumdiphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples.
Chromium-compounds; Analytical-chemistry; Analytical-processes; Ultrasonics; Ultrasonic-testing; Statistical-analysis; Analytical-methods; Analytical-models; Analytical-processes; Chemical-analysis; Workplace-studies; Air-monitoring; Air-quality; Air-sampling; Air-samples; Air-contamination
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Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division