Nanosensing of Pesticides by Zinc Oxide Quantum Dot: An Optical and Electrochemical Approach for the Detection of Pesticides in Water

Abstract

Present study reveals the low concentrations (∼4 ppm) of pesticide sensing vis-à-vis degradation of pesticides with the help of nontoxic zinc oxide quantum dots (QD). In our study, we have taken four different pesticides viz., aldrin, tetradifon, glyphosate, and atrazine, which are widely used in agriculture and have structural dissimilarities/diversity. By using optical sensing techniques such as steady state and time-resolved fluorescence, we have analyzed the detailed exciton dynamics of QD in the presence of different pesticides. It has been found that the pesticide containing good leaving groups (-Cl) can interact with QD promptly and has high binding affinity (∼10 M). The different binding signatures of QD with different pesticides enable us to differentiate between the pesticides. Time resolved fluorescence spectroscopy provides significant variance (∼150-300 ns) for different pesticides. Furthermore, a large variation (10 Ω to 7 × 10 Ω) in the resistance of QD in the presence of different pesticides was revealed by electrochemical sensing technique. Moreover, during the interaction with pesticides, QD can also act as a photocatalyst to degrade pesticides. Present investigation explored the fact that the rate of degradation is positively affected by the binding affinity, i.e., the greater the binding, the greater is the degradation. What is more, both optical and electrochemical measurements of QD, in tandem, as described in our study could be utilized as the pattern recognition sensor for detection of several pesticides.

Nano-enabled agriculture: from nanoparticles to smart nanodelivery systems

“…CNTs paste electrodes (CNTPE) were used for determining herbicide fenclorim in soils (Raveendranath Babu et al 2014). Sahoo et al (2018) revealed that ZnO QD could be used to sense low concentrations (,4 mg L À1 ) of four widely used pesticides (aldrin, tetradifon, glyphosate and atrazine) in agriculture. However, despite the above promising findings, few devices are currently being used in commercial agriculture, mainly as a result of the interferences from complex targets, harsh detection environments and high costs (Neethirajan et al 2018).…”

Metal oxide QD based ultrasensitive microsphere fluorescent sensor for copper, chromium and iron ions in water

“…The water-soluble uorescent ZnO-QDs capped by APTES were prepared following the protocol of Dibakar et al 36,37 Initially, 1% (w/v) carboxymethyl cellulose solution was prepared by dissolving carboxymethyl cellulose powder in double distilled water under stirring at 1500 rpm for 12 h. The uorescent zinc oxide quantum dot capped with APTES (0.5 mg dry weight) were solubilised in 500 mL of double distilled water by ultrasonication for 30 min and added into 5 mL of carboxymethyl cellulose solution followed by incubation under stirring (1500 rpm) for 5 h at 30 C. Now uorescent zinc oxide quantum dotcarboxymethyl cellulose microsphere (ZCM) was prepared by water-in oil emulsion method. The ZCM solution was then added dropwise ($1 mL min À1 ) into 25 mL of light liquid paraffin containing 100 mL of Tween-80 under stirring at 1800 rpm to form water-in-oil emulsion.…”

Ratiometric Strategy for Electrochemical Sensing of Carbaryl Residue in Water and Vegetable Samples

“…Given the above disadvantages, an electrochemical sensor (ECS) becomes promising as an inexpensive, fast, portable tool for tracing pesticide residue on a large scale. Nevertheless, background electric signals of the workstation, variable environmental conditions (e.g., temperature, pH and pollutants), diversity among electrodes, and a complex matrix of samples affect the reproducibility of ECS significantly [7,8]. As it is hard to avoid these variations adopting traditional ECS with single-signal In order to resolve this problem, RECS introduces an inner reference signal to build a self-rectification calibration, because the reference probe and target analyte are affected by the same sensing interface.…”