Voltammetric determination of DNA based on its interaction with neutral red

A new linear sweep vo ltammetric (LSV) assay of fsDNA based on its interaction with neutra l red (N R) is presented. At pH 8.0 Britton-Robinson (8-R) buffe r solutio n, the dye can bind with DNA to form a supramolec ular complex , wh ich results in the decrease of the linear sweep voltammetric reductive peak current at -0.60 V (vs. SCE) on the mercury e lec trode. The binding reaction is completed within 20 min at room temperature and remains stable for at least 2 hours. The optimal conditions for the binding reaction and the e lec troc hemical detection have been determined. Under the optimal conditions there is little interference from most metal ion s and amino ac ids. The calibration graph for fsDNA is linear in the range of 1.0-30.0 mg/L with the linear regress io n equation as Mr"(nA)=28.20C (mg/ L)+ I 0.84 (n=9, y=0.992) and the detection limit as 0.67 mg/L. The interacti on mechani sm is charac te ri zed by the aggregation of DNA-NR supramolecular compl ex by UV-vis absorption spectrophotometry and cyclic voltammetry. The sto ichiometry of thi s supramolecular complex has been calcul ated with the binding number as 1.5 and the binding constant as 1.73x 10• IPC Code: Int. C l GOIN27/00; C I2Q/68