Method for the determination of hexavalent chromium using ultrasonication and strong anion exchange solid phase extraction

• Main Authors: WANG JIN, ASHLEY KEVIN
• Format: Patent
• Language: English
• Published: 26.10.2004
• Edition: 7
• Subjects: GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TESTING

A method for the determination of hexavalent chromium (Cr) 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). Using ultrasonic extraction in combination with a strong anion exchange solid phase extraction (SAE-SPE) technique, the filtration, preconcentration, and isolation of Cr in the presence of other chromium species and interferents was achieved. The method generally involves: (1) ultrasonication in basic buffer solution to extract Cr from environmental matrices; (2) strong anionic exchange solid phase extraction to separate Cr from other chromium species and potential interferents; (3) acidification of the eluate containing the Cr ions; (4) complexation of Cr with a complexing agent to form a soluble, colored Cr-complex; and (5) spectrophotometric determination of the colored Cr-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.