title: Spectrophotometric determination of mercury in water samples after preconcentration using dispersive liquid-liquid microextraction.
abstract: A simple method for the determination of mercury in water samples after preconcentration using dispersive liquid-liquid microextraction is described. The procedure is based on the extraction of mercury in the form of a complex and its subsequent determination by spectrophotometry. The complex is formed between Hg(II) and 2-(2-benzothiazolylazo)-p-cresol. The detection at 650 nm is performed directly in the metal-rich phase, which is spread on a triacetylcellulose membrane. The method eliminates the need to use a cuvet or large quantities of samples and reagents. The parameters that influence the preconcentration were studied, and the analytical characteristics were determined. The enrichment factor and the consumptive index for this method were 64 and 0.16 mL, respectively. The LOD (3.3 microg/L) and LOQ (11.1 microg/L) were also determined. The accuracy of the method was tested by the determination of mercury in certified reference materials BCR 397 (Human Hair) and SRM 2781 (Domestic Sludge). The method was applied to the determination of mercury in samples of drinking water, sea water, and river water.
authors.affiliation: Universidade Estadual do Sudoeste da Bahia, Laboratório de Química Analítica (LQA), Campus de Jequié, 45206-190 Jequié, Bahia, Brazil. vlemos@uesb.edu.br
authors.forename: Valfredo Azevedo
authors.initials: VA
authors.lastname: Lemos
authors.forename: Liz Oliveira
authors.initials: LO
authors.lastname: dos Santos
authors.forename: Eldevan dos Santos
authors.initials: Edos S
authors.lastname: Silva
authors.forename: Emanuel Vitor dos Santos
authors.initials: EV
authors.lastname: Vieira
mesh_terms: D002138:Calibration; D002482:Cellulose / Q000031:analogs & derivatives; D005618:Fresh Water / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D059625:Liquid-Liquid Extraction / Q000379:methods; D008567:Membranes, Artificial; D008628:Mercury / Q000032:analysis*; D012015:Reference Standards; D012623:Seawater / Q000032:analysis; D012996:Solutions; D012997:Solvents; D013048:Specimen Handling; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014867:Water / Q000032:analysis*; D014881:Water Supply / Q000032:analysis
chemical_list: D007202:Indicators and Reagents; D008567:Membranes, Artificial; D012996:Solutions; D012997:Solvents; D014867:Water; D002482:Cellulose; C024671:cellulose triacetate; D008628:Mercury