| 摘要 |
A method for the determination of hexavalent chromium (Cr<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<VI>). By means of ultrasonic extraction in combination with a strong anion exchange solid phase extraction (SAE-SPE) technique, the filtration, preconcentration, and isolation of Cr<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<VI> from environmental matrices; (2) strong anion exchange solid phase extraction to separate Cr<VI> from other chromium species and potential interferents; (3) acidification of the eluate containing the Cr<VI> ions; (4) complexation of Cr<VI> with a complexing agent to form a soluble, colored Cr<VI>-complex; and (5) spectrophotometric determination of the colored Cr<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.
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