Fabrication of Zr(IV) Modified Gold Electrode via Layer-by-Layer Self-Assembly for Methyl Parathion.

A facile way was developed to fabricate Zr(IV) cation modified gold electrode for high-performance electrochemical sensing of methyl parathion (MP) via layer-by-layer self-assembly. The electrode was prepared by sequentially absorbing 11-mercaptoundecyl-phosphoric acid (MDPA) and Zr(IV) cation on gold electrode through strong chelating interactions between gold and -SH as well as Zr(IV) cation and phosphoric groups of MDPA. Fourier transform infrared spectrophotometry, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and cyclic voltammetry were employed for the characterization of morphologies and electrochemical properties. The sensor was used to determine MP by square wave voltammetry. The cathodic peak current (at + 0.25 V vs saturated calomel electrode) increases linearly in the range of 1.0 - 180.0 ng ml-1 under optimized conditions. And the detection limit is low to 0.22 ng ml-1 (based on a signal-to-noise ratio of 3). The electrode is successfully used to detect MP in the real water sample with recoveries of 98.97%-102.4% and RSDs of 0.21%-1.99% (n = 3) at three spiked levels. The proposed method provides one simple way to prepare Zr(IV) cation modified electrode for the fast determination of MP. The reliability and accuracy of the method is validated by independent assays with HPLC. [ABSTRACT FROM AUTHOR]