A new molecularly imprinted polymer (MIP)-based electrochemical sensor for monitoring 2,4,6-trinitrotoluene (TNT) in natural waters and soil samples

摘要

A high selective voltammetric sensor for 2,4,6-trinitrotoluene (TNT) was introduced. TNT selective MIP and non-imprinted polymer(NIP) were synthesized and then used for carbon paste (CP) electrode preparation. The MIP, incorporated in the carbon paste electrode, functioned as selectively recognition element and pre-concentrator agent for TNT determination. The prepared electrode was used for TNT measurement by the three steps procedure, including analyte extraction in the electrode, electrode washing and electrochemical measurement of TNT. The MIP-CP electrode showed very high recognition ability in comparison to NIP-CP. It was shown that electrode washing after TNT extraction led to enhanced selectivity. The response of square wave voltammetry for TNT determination by proposed electrode was higher than that of differential pulse voltammetry. Some parameters affecting sensor response were optimized and then a calibration curve plotted. A dynamic linear range of 5 x 10(-9) to 1 x 10(-6) Mol l(-1) was obtained. The detection limit of the sensor was calculated equal to 1.5 x 10(-9) mol l(-1). This sensor was used successfully for TNT determination in different water and soil samples.