title: Chromium(III) determination with 1,5-diphenylcarbazide based on the oxidative effect of chlorine radicals generated from CCl4 sonolysis in aqueous solution.
abstract: Oxidation of Cr(III) during sonication in carbonated aqueous solutions saturated with CCl4 leads to the quantitative formation of Cr(VI) and provides a simple and rapid method for spectrophotometric chromium determination with 1,5-diphenylcarbazide. The key to this method is the production of chlorine radicals when aqueous solution saturated with CCl4 is exposed to ultrasonic waves of 40 kHz. The effects of sonication period, CCl4 solution volume, acidity, and interferences were discussed. The time required for a single determination is lower than 2 min. The relative standard deviation obtained for aqueous solutions with 1 microg of Cr was < 2% (N = 10) and the calculated detection limit (3sigma) was 5 ng of Cr.
authors.affiliation: Instituto de Química, Universidade Federal da Bahia, Campus de Ondina, 40.170-290 Salvador, Bahia, Brazil.
authors.forename: Sivanildo da Silva
authors.initials: Sda S
authors.lastname: Borges
authors.forename: Mauro
authors.initials: M
authors.lastname: Korn
authors.forename: José Luis Fontes da Costa
authors.initials: JL
authors.lastname: Lima
mesh_terms: D002251:Carbon Tetrachloride / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D004160:Diphenylcarbazide; D005609:Free Radicals / Q000737:chemistry; D010084:Oxidation-Reduction; D012996:Solutions; D013010:Sonication; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000517:prevention & control
chemical_list: D005609:Free Radicals; D012996:Solutions; D014874:Water Pollutants, Chemical; D002857:Chromium; D004160:Diphenylcarbazide; D002713:Chlorine; D002251:Carbon Tetrachloride