Ratiometric electrochemical analysis on a flexibly-fabricated vibratory electrode module for reliable and selective determination of imidacloprid

Excessively-used imidacloprid (IMI) leads to considerable pollutions. Feasible and reliable IMI detections are in great need. Therefore, we introduce the ratiometric IMI analysis on a flexibly-fabricated vibratory electrode module. In this system, beta-cyclodextrin is chosen as a supramolecular recognizer to capture IMI, and Prussian blue (PB) acts as an internal reference. The reference current (IPB) presents remarkable stability with different IMI concentrations, while shows an identical fluctuant tendency to IMI current (IIMI) against interferences. The ratiometric readout (IIMI/IPB) is proven to be a more reliable indicator to quantize IMI. The as-fabricated sensor integrates a tri-electrode system and a vibration motor to improve IMI adsorption. The flexible module is prepared following well-proven industrial techniques of flexible print circuit. Fabrications and modifications of the sensor are morphologically examined. Synergistic characteristics in the ratiometric analysis are validated and optimized with electrochemical methods. Under optimum conditions, vibration-enhanced determinations are applied to laboratory and natural samples. Detection limit and linear range are well found as 6.1 x 10(-8) mol L-1 and 2 x 10(-7)-1.2 x 10(-4) mol L-1, respectively. The applicability for the natural samples is further validated with recovery tests and certified HPLC. Given this, this method can be treated as a promising tool for IMI determination in broad sources.

Automated summary

A novel ratiometric IMI analysis method was developed using beta-cyclodextrin and Prussian blue as recognition and reference molecules. The sensor showed high reliability and stability in IMI quantification, achieving good detection results in both laboratory and natural samples.