title: Voltammetric studies on the potent carcinogen, 7,12-dimethylbenz[a]anthracene: Adsorptive stripping voltammetric determination in bulk aqueous forms and human urine samples and detection of DNA interaction on pencil graphite electrode.
abstract: 7,12-Dimethylbenz[a]anthracene (DMBA), is a widely studied polycyclic aromatic hydrocarbon that has long been recognized as a very potent carcinogen. Initially, the electrochemical oxidation of DMBA at the glassy carbon and pencil graphite electrodes in non-aqueous media (dimethylsulphoxide with lithium perchlorate) was studied by cyclic voltammetry. DMBA was irreversibly oxidized in two steps at high positive potentials, resulting in the ill-resolved formation of a couple with a reduction and re-oxidation wave at much lower potentials. Special attention was given to the use of adsorptive stripping voltammetry together with a medium exchange procedure on disposable pencil graphite electrode in aqueous solutions over the pH range of 3.0-9.0. The response was characterized with respect to pH of the supporting electrolyte, pre-concentration time and accumulation potential. Using square-wave stripping mode, the compound yielded a well-defined voltammetric response in acetate buffer, pH 4.8 at +1.15V (vs. Ag/AgCl) (a pre-concentration step being carried out at a fixed potential of +0.60V for 360s). The process could be used to determine DMBA concentrations in the range 2-10nM, with an extremely low detection limit of 0.194nM (49.7ngL(-1)). The applicability to assay of spiked human urine samples was also illustrated. Finally, the interaction of DMBA with fish sperm double-stranded DNA based on decreasing of the oxidation signal of adenine base was studied electrochemically by using differential pulse voltammetry with a pencil graphite electrode at the surface and also in solution. The favorable signal-to-noise characteristics of biosensor resulted in low detection limit (ca. 46nM) following a 300-s interaction. These results displayed that the electrochemical DNA-based biosensor could be used for the sensitive, rapid, simple and cost effective detection of DMBA-DNA interaction.
authors.affiliation: Yüzüncü Yil University, Faculty of Science and Letter, Department of Analytical Chemistry, Campus Zeve, 65080 Van, Turkey.
authors.forename: Y
authors.initials: Y
authors.lastname: Yardim
authors.forename: E
authors.initials: E
authors.lastname: Keskin
authors.forename: A
authors.initials: A
authors.lastname: Levent
authors.forename: M
authors.initials: M
authors.lastname: Ozsöz
authors.forename: Z
authors.initials: Z
authors.lastname: Sentürk
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism* / Q000652:urine; D000327:Adsorption; D000328:Adult; D002273:Carcinogens / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D008297:Male; D014867:Water / Q000737:chemistry*; D014956:Writing
chemical_list: D002273:Carcinogens; D014867:Water; D015127:9,10-Dimethyl-1,2-benzanthracene; D006108:Graphite; D004247:DNA