Studies On New-type Electrochemical Sensors Determination Of Environmental Organic Pollutants

In recent years, the development of electrochemical sensor is very quick. Compared to other techniques, it has fast response, simple operation, short analytical time and the ability to be miniaturized. Modified electrode material as the most significant part of sensor has aroused great interests.In this paper, NiFe2O4/MWCNTs, ILs@LiFe5O8/MWCNTs, ILs@CdFe2O4/Ni nanohybrids were synthesized, and we have constructed new-type sensor.The method was satisfactorily employed to analyze benomyl, BPAP and BPS.The NiFe2O4/MWCNTs composite was fabricated by a one-step hydrothermal method. NiFe2O4/MWCNTs/GCE sensor was constructed todetectbenomyl, the chronocoulometric results indicated that the specific area of the modified electrodes is as nearly 6 times as the bare electrode. The electrochemical behavior of benomyl was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). NiFe2O4/MWCNTs/GCE showed excellent electrocatalytic activity toward benomyl.It indicated that the redox ofbenomyl on NiFe2O4/MWCNTs/GCE is an adsorption-controlled process, and it can be deduced that the proton number is equal to that of the number of transferred electrons.In the phosphate buffer (PBS) of pH 6.0, the linear relationship ofbenomyl was from 1.00×10-6 mol/L to 1.00×10-4 mol/L, The detection limit of benomyl was 2.51 × 10-7 mol/L (S/N=3). The proposed method was successfully applied to determine benomyl in real samples with satisfactory results. Moreover, the NiFe2O4/MWCNTs/GCE showed good reproducibility, stability, and anti-interference.ILs@LiFe5O8/MWCNTs/GCE sensor was constructed to detect BPAP. The introduction of ILscould greatly improve the current response of sensor.Modified electrodeshowed excellent electrocatalytic activity toward BPAP, It indicated that the redox ofBPAP onILs@LiFe5O8/MWCNTs/GCE is an adsorption-controlled process, and it can be deduced that the proton number is equal to that of the number of transferred electrons.In the phosphate buffer (PBS) of pH 5.0, the linear relationship of BPAP was from 1.034×10-9 mol/L to 2.069x 10-6 mol/L, the detection limit of BPAP was 8.197×10-10 mol/L (S/N=3). ILs@LiFe5O8/MWCNTs/GCE showed well reproducibility, stability, and anti-interference.Moreover, satisfactory results indicated that ILs@LiFe5Og/MWCNTs nanohybrid was well for the trace-level analysis of BPAP in real samples.Ni-doped CdFe2O4 nanocomposite was fabricated successfully,and thencombined with ILs which have wider electrochemical windows, ILs@CdFe2O4/Ni/GCE was constructed for simultaneous determination of BPAP and BPS.The electrochemical behavior of BPAP and BPS was investigated. NiFe2O4/MWCNTs/GCE showed excellent electrocatalytic activity toward benomyl, ΔEP between BPAP and BPS is 310 mV. In the phosphate buffer (PBS) of pH 6.0, the linear relationship of BPAP was from 6.89×10"9 mol/L to 6.89×10-6 mol/L, the detection limit of BPAP was 5.37×10-9 mol/L (S/N=3). the linear relationship of BPS was from 8.00x 10"9 mol/L to 8.00x 10-6 mol/L, the detection limit of BPAP was7.19×10-9 mol/L (S/N=3) ILs@CdFe2O4/Ni/GCE showed well reproducibility, stability, and anti-interference. Moreover, satisfactory results indicated thatILs@CdFe2O4/Ni/GCE nanohybrid was well for simultaneous determination of BPAP and BPS in real samples.