Electrochemical Behaviour and Determination of Paraquat on the Glassy Carbon Electrode Modified with Montmorillonite and Ionic Liquid

KeyWord:ionic liquid  montmorillonite(MMT)  paraquat£¨PQ£©  square wave voltammetry

Abstract:

      A novel PTA-MMT and£ÛBMIM£ÝPF6 modified glassy carbon electrode£¨PTA-MMT-£ÛBMIM£ÝPF6/GCE£© was prepared and successfully used for the determination of paraquat£¨PQ£©.The modified film was characterized by infared£¨IR£© spectrometry.The charge transfer resistance of PQ on PTA-MMT-£ÛBMIM£ÝPF6/GCE was the lowest by comparing the nyquist plots of the electrode before and after modification.The cyclic voltammetric behavior of PQ on modified electrode was studied. The results showed that£¬in pH 8ª±0 phosphate buffer solution£¨PBS£©£¬two pairs of redox peaks were observed on the modified electrode.The oxidation peak current was linear to scan rates in the range of 40-360 mV?s-1£¬indicating that the electrode process of PQ was controlled by absorption.The reaction electronic number and active area of PQ on PTA-MMT-£ÛBMIM£ÝPF6/GCE were obtained to be 2 and 0ª±064 4 cm2£¬respectively.The effects of modifier dosage£¬buffer solution types and pH values for the determination of PQ were discussed.Under the optimized conditions£¬the correlation between peak current£¨Ipa£© and PQ concentration was studied by square wave voltammetry£¬and a good linear relationship was obtained over PQ concentration in the range of 5ª±0¡Á10-7-2ª±5¡Á10-4 mol?L-1.The linear equation was Ipa£¨¦ÌA£©=-1ª±024-23ª±683c£¨r=0ª±999 3£© and the detection limit was 2ª±07¡Á10-7 mol?L-1.The spiked recoveries were in the range of 93%-104%.The modified electrode exhibited good repeatability and stability.