Novel Paraquat Detection Strategy Enabled by Carboxylatopillar[5]arene Confined in Nanochannels on a Paper-Based Sensor

Abstract

Paper-based optical sensors have emerged as a promising technology for pesticide detection and attracted extensive attention. However, in practical analytical applications, it may suffer from limited sensitivity with traditional signal amplification strategies. Here, we developed a novel mesoporous silica-modified paper-based sensor for a sensitive capture and analysis of the pesticide paraquat. Carboxylatopillar[5]­arene was covalently introduced into the nanochannels for the rapid capture of target paraquat molecules due to the mass transfer confinement effect within nanopores. In addition, the large specific surface area of mesoporous silica enabled high-abundance immobilization of the capture agent and promoted its binding efficiency, which, in turn, contributed to improving the sensitivity. This work highlights the great potential of nanochannels as a development platform for sensitive paper-based sensors that can be used to develop new systems for the detection of paraquat and even other pesticides.

Tailoring the Coordination Environment of Fe/Zn-BDC to Boost Peroxidase-like Activity for Highly Selective Detection of PFOS

“…The phenomenon signified that the metal−oxygen bond strength was weakened due to the interaction of metal centers Fe/Zn with other substances by forces. 41 Combined with the XPS spectral analysis of Fe 2p 3/2 (Figure 5b), the movement of Fe 2p 3/2 toward higher binding energy after PFOS adsorption might have been due to the coordination of part of the PFOS with Fe to form a ligand bond. Then, the strongly electronegative F atoms of PFOS induced a charge density decrease of Fe centers in Fe/Zn-BDC-F 4 , leading to the oxidation of Fe.…”

“…The spectrum of Fe/Zn-BDC-F 4 had a prominent broad peak at 491 cm –1 , suggesting the existence of metal–oxygen bonds (Zn–O and Fe–O). , After PFOS adsorption, this peak underwent a red-shift to 470 cm –1 , accompanied by a substantial reduction in intensity. The phenomenon signified that the metal–oxygen bond strength was weakened due to the interaction of metal centers Fe/Zn with other substances by forces . Combined with the XPS spectral analysis of Fe 2p 3/2 (Figure b), the movement of Fe 2p 3/2 toward higher binding energy after PFOS adsorption might have been due to the coordination of part of the PFOS with Fe to form a ligand bond.…”

Recent Advances of Food Hazard Detection Based on Artificial Nanochannel Sensors

“…The nanochannel sensors constructed by this method can be extended to sensitive electrochemical analysis in the fields of medicine, biology, food, and the environment. In another research, Wang et al 86 developed a novel mesoporous silica nanochannel-modified paper-based sensor based on fluorescence spectroscopy for the recovery and highly sensitive detection of the pesticide paraquat.…”