Fluorescent and Colorimetric Ionic Probe Based on Fluorescein for the Rapid and On-Site Detection of Paraquat in Vegetables and the Environment

Abstract

Detection of pesticide paraquat (PQ) is of considerable significance to ensure food safety, and its rapid and on-site detection is still a challenge. Aimed at the ion characteristics of PQ, an “enrichment and detection” strategy was proposed to improve the sensitivity through electrostatic attractions, and the ion characteristic of probes was adopted to increase the portability through avoiding aggregation-caused quenching effects in the paper strips. Herein, a novel anion-functionalized ionic liquid (IL) probe with a large conjugated plane and rich π-electrons ([Fluo][P66614]2) was designed as a fluorescent and colorimetric dual-channel probe to sensitively and rapidly detect trace amounts of PQ in vegetables and the environment. The proposed probe exhibited good linearity with a detection limit of 64.0 nM in the PQ concentration range of 0.3–7.0 μM (fluorometry) and 0.1 μM in that of 0.1–8.0 μM (colorimetry), respectively. In addition, it displayed a rapid fluorescence quenching response from green to dark (<5 s) and excellent anti-interference (among 23 other pesticides) due to dual effects of electrostatic attraction and π–π stacking. Most importantly, the lipophilic IL probe could be applied in real vegetables and environmental samples with a satisfying recovery rate of 98–103% and assembled into a handy paper strip that achieved the visual semiquantitative detection of PQ. This ionic probe provides a feasible approach for rapidly and conveniently detecting PQ for ensuring agricultural and food safety and opens a new avenue to detect ion-responsive analytes in real complex samples by an “enrichment and detection” strategy.

Design and One-Pot Ultrasound Synthesis of Inorganic Base-Promoted Fluorescent Ligand-Gated Ion Channel Fused Arylpyrazole Sulfonamide Skeletons to Enhance Phloem Mobility and Insecticidal Activity as GABA and nACh Receptors Inhibitors

“…The findings can be used to detect the residual amount of APSn M in plants. Che et al designed an anionic probe with a large conjugate surface and abundant π electrons for the cationic nature of paraquat (PQ), which can specifically detect residual PQ in vegetables and fruits . Fipronil had poor fluorescence, and the fluorescence intensity of the ligand-gated ion channel was significantly enhanced, which can improve the sensitivity of its fluorescence detection.…”

A portable smartphone platform utilizing dual-sensing signals for visual determination of semicarbazide in food samples

“…Fluorescence technology has attracted widespread attention owing to its high specificity, prompt analysis capacity, and easy operation. 24,25 Luminescent porous materials such as upconversion luminescent nanosensors, metal-organic frameworks (MOFs), hydrogen-bonded organic frameworks (HOFs), covalent organic frameworks (COFs), coordinated polymers (CPs), porous organic polymers (POPs), and quantum dots have been developed for the detection of NFZ. [26][27][28][29][30][31][32] However, it is worth noting that monitoring the residue of NFZ is unsuitable in food samples because highly unstable NFZ is prone to metabolize into SEM in the body, which cannot accurately reflect antibiotic residues.…”

A Sensitive Colorimetric and Near-Infrared Fluorescent Probe for Tracing Slight pH Variation in Food Samples

“…Thus, the fluorescent probe showing fluorescence response to pH in the NIR region is desirable. (3) Recently, fluorescent probe-based test papers have drawn much attention for on-site nondestructive monitoring of pathogens, , pesticide, , antimicrobial agent, reactive oxidizing agent, spoilage, , quality, and safety , in various food samples. In order to fabricate the test paper for on-site monitoring pH variation in food samples, the probe should exhibit colorimetric response to pH, so that the readout could be simply acquired by the naked eyes without sophisticated operations and expensive instruments.…”