title: Electrothermal atomic absorption spectrometric determination of cobalt in biological samples and natural waters using a flow injection system with on-line preconcentration by ion-pair adsorption in a knotted reactor.
abstract: An on-line flow injection preconcentration-ETAAS method is developed for trace determination of cobalt in biological materials and natural samples by ion-pair sorption on the inner walls of a PTFE knotted reactor. The ion-pair is formed between the negatively charged cobalt-nitroso-R-salt complex and the tetrabutylammonium counter-ion. An enhancement factor of 15, a sampling frequency of 17 and a concentration efficiency of 4 are obtained for a preconcentration time of 60 s and a sample loading flow rate of 5 mL min(-1). The detection limit (3sigma) is 5 ng L(-1). The relative standard deviation at the 0.2 microg L(-1) level is 2.3%. The analytical results obtained for standard reference materials are in good agreement with the certified or indicated values and satisfactory recoveries of spiked cobalt in tap water are obtained.
authors.affiliation: Department of Chemistry, University of Antwerp, Wilrijk, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Benkhedda
authors.forename: H G
authors.initials: HG
authors.lastname: Infante
authors.forename: E
authors.initials: E
authors.lastname: Ivanova
authors.forename: F
authors.initials: F
authors.lastname: Adams
mesh_terms: D000818:Animals; D016477:Artifacts; D049872:Bivalvia; D003035:Cobalt / Q000032:analysis*; D005399:Fishes; D009132:Muscles / Q000737:chemistry*; D012015:Reference Standards; D013054:Spectrophotometry, Atomic / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D003035:Cobalt