Modified Screen-Printed Potentiometric Sensors based on Man-Tailored Biomimetics for Diquat Herbicide Determination.

Ayman H Kamel,Nashwa S Abdalla,Abd El-Galil E Amr,Abdulrahman A Almehizia,Mohamed El-Naggar,Mohamed A Al-Omar

doi:10.3390/ijerph17041138

Abstract

Screen-printed platforms integrated with molecularly imprinted polymers (MIP) were fabricated and characterized as potentiometric sensors for diquat (DQ). The synthesized MIP beads were studied as sensory carriers in plasticized poly(vinyl chloride) membranes. The sensors were constructed by using poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material to diminish charge-transfer resistance and water layer potential. Conventional ion-selective electrodes (ISEs) with internal filling solution were used for comparison. The designed electrodes showed near Nernstian slopes of 28.2 ± 0.7 (r² = 0.999) over the concentration range of 1.0 × 10−6–1.0 × 10−2 M with the limit of detection 0.026 µg/mL over the pH range 4.2–9.0. The electrode exhibited good selectivity for diquat cations over a large number of organic and inorganic cations. The sensor was successfully introduced for direct measurement of diquat content in commercial pesticide preparations and different spiked potato samples. The results showed that the proposed electrode has a fast and stable response, good reproducibility, and applicability for direct assessment of diquat content. The proposed potentiometric method is simple and accurate in comparison with the reported HPLC methods. Besides, it is applicable to turbid and colored sample solutions.

Highlights

Pesticides and herbicides are extensively used in agriculture, forestry, and domestic activities for controlling pests
We present miniaturized planar potentiometric ion-selective electrodes (ISEs) modified with poly(3,4-ethylenedioxythiophene) (PEDOT) as solid-contact material for selective detection of diquat (DQ) herbicide
The imprinting process of diquat was examined using Fourier-transform infrared spectroscopy (FT-IR) technique and the measurements were carried out using the FT-IR spectrometer (Alpha II, Bruker ABCO, Cairo, Egypt) using the attenuated total reflection (ATR) technique

Summary

Introduction

Pesticides and herbicides are extensively used in agriculture, forestry, and domestic activities for controlling pests. This rapid increase in their use can cause a real threat to the environment and human health. A highly restricted control must be followed to avoid unacceptable levels of these contaminants from entering the water environment, influencing the food chain of humans and animals [1]. A group of quaternary ammonium salts, is considered a uneasy type of herbicide [2], attributed to their physico-chemical properties, which lags the known multi-residue methods from their quantification. Diquat (1,10 -dimethyl-4,40 -bipyridilium dibromide) is one of the. Res. Public Health 2020, 17, 1138; doi:10.3390/ijerph17041138 www.mdpi.com/journal/ijerph

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