Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

48TruenessTrueness was determined in standard referencematerial CRM 12-3-10 by on-line FTC-GFAAS ofthe total Sb.The FTC-GFAAS technique developed at theseconditions have some limitations. It is suitable onlyfor determination of Sb(III) species and total Sbmust be converted to the Sb(III) form. Many publicationswere pointed to the selective reduction oftotal Sb to Sb(III) form. As appropriate procedurefor selective reduction step seems to be utilizingL-cysteine [8].CONCLUSIONSThe aim of this work was to develop an on–linecoupling of electrochemical preconcentration to theAAS method and the utilization of the developedsystem for the determination of ultra-trace amountsof Sb in water samples. The flow-through electrochemicalanalyzer EcaFlow (model GLP 150, Istran,Bratislava) was used as the preconcentrationunit with a two-electrode cell. The working electrodewas a RVC electrode coated with gold. TheAAS spectrometer Spectraa 400 with the graphitefurnace atomizer (Varian) was used to measure thepreconcentrated Sb species. The preconcentrationparameters for the electrochemical process wereoptimized. The deposition runs at a constant currentof –8000 µA and the optimum stripping currentwas found to be 150 µA.The deposition was made from the hydrochloricacid solution, which was then on-line replacedby a diluted nitric acid facilitating the AAS measurementof Sb. The advantage of the used preconcentrationsystem was in an automatic and reliablematrix exchange facility. Optimum electrolyte concentrationswere found to be 1 mol.dm –3 HCl and2 mol.dm –3 HNO 3for the deposition and stripping/AAS measurement, respectively.AcknowledgementThis work was supported by the application research(Project No. 451).REFERENCES1. PROUSEK, J.: Hazarded properties of the substances.Bratislava: STU, 2001.2. PRADOSH, R., ANUPAMA, S.: Current Science.1997, 82, 1.3. STN EN ISO 15586: Quality of the water: Determinationof trace elements by electrothermal atomicabsorption spectrometry. 2003.4. MENEMENLIOGLU, I., KORKMAZ, D., ATA-MAN, O. Y.: Spectrochimica Acta. 2007, Part B62 40–47.5. ANTHEMIDIS, A. N., KATZAMANIDOU, A.: 5thAegean Analytical Chemistry Days (AACD), Thessaloniki,2006.6. BEINROHR, E., MANOVA, A., DZUROV, J.: Preconcentrationof Cr(III) and total Cr in waters forflame AAS in a flow-through electrochemical/sorptioncell. Fresenius J Anal Chem, 1996, 355(5–6),p. 528–531.7. MOCAK, J, BOND, A. M., MITCHELL, S., SCOL-LARY, G.: A statistical overview of standard (IUPACand ACS) and new procedures for determining thelimits of detection and quantification: Application tovoltammetric and stripping techniques (technical report).Pure and Appl. Chem, 1997, 69(2), p. 297–328.8. HENGWU CHEN, IAN D, BRINDLE, XIAO-CHUN LE: Prereduction of arsenic(v) to arsenic(iii),enhancement of the signal, and reduction of interferencesby l-cysteine in the determination of arsenicby hydride generation, Anal. Chemistry, 1992, 64(6),667–672