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Method for the determination of hexavalent chromium using ultrasonication and strong anion exchange solid phase extraction.
Wang J; Ashley KE
U S Patent 6,808,931 2004 Oct; :1-13
A method for the determination of hexavalent chromium (Cr.sup.VI) in environmental and industrial hygiene samples is provided. Based on the chemical properties of chromium species in aqueous solutions, a simple, fast, sensitive, and economical field method has been developed and evaluated for the determination of hexavalent chromium (Cr.sup.VI). Using ultrasonic extraction in combination with a strong anion exchange solid phase extraction (SAE-SPE) technique, the filtration, preconcentration, and isolation of Cr.sup.VI in the presence of other chromium species and interferents was achieved. The method generally involves: (1) ultrasonication in basic buffer solution to extract Cr.sup.VI from environmental matrices; (2) strong anionic exchange solid phase extraction to separate Cr.sup.VI from other chromium species and potential interferents; (3) acidification of the eluate containing the Cr.sup.VI ions; (4) complexation of Cr.sup.VI with a complexing agent to form a soluble, colored Cr.sup.VI -complex; and (5) spectrophotometric determination of the colored Cr.sup.VI -complex. Preferably, the ultrasonication step is carried out in the presence of a slightly basic ammonium buffer and the complexing agent is 1,5-diphenylcarbazide.
Chromium-compounds; Analytical-methods; Analytical-chemistry; Analytical-processes; Ultrasonics; Ultrasonic-testing
U S Patent 6,808,931
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