title: Amperometric biosensor based on denatured DNA for the study of heavy metals complexing with DNA and their determination in biological, water and food samples.
abstract: Amperometric biosensor (BS) has been elaborated based on the stationary mercury-film electrode (SMFE) with silver support and cellulose nitrate (CN) membrane containing immobilized single-stranded DNA (ssIDNA). The sorption isotherms and ssDNA-heavy metal binding constants have been obtained with the BS. According to these data, the chosen heavy metals form the following series of binding strength with ssIDNA: Pb(II)>Fe(III)>Cd(II). It has been found that upon the competitive adsorption, there exists practically simultaneous sorption of different ions at ssIDNA containing membrane. The method of the determination of heavy metals based on preconcentration of metal ions on the BS followed by the destruction of DNA-metal complexes with ethylenediamine tetraacetate (EDTA) and voltammogram recording has been proposed. The lower limits of detectable contents are 1.0x10(-10), 1.0x10(-9) and 1.0x10(-7) mol l(-1) for Pb(II), Cd(II) and Fe(III), respectively. Heavy metals have been assayed in natural and drinking water, milk and blood serum samples even under simultaneous presence with a selectivity factor of 1:10. The effect of matrix components has been estimated.
authors.affiliation: Chemical Faculty, Kazan State University, Kremlevskaya Street, 18, Kazan 420008, Russia. sofia-babkina@mail.ru
authors.forename: S S
authors.initials: SS
authors.lastname: Babkina
authors.forename: N A
authors.initials: NA
authors.lastname: Ulakhovich
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D001774:Blood Chemical Analysis / Q000379:methods*; D002645:Chickens; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods; D005504:Food Analysis / Q000379:methods*; D019216:Metals, Heavy / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D009691:Nucleic Acid Denaturation; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D020099:Coated Materials, Biocompatible; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D004247:DNA