A novel platform based on CoMn2O4-rGO/1-ethyl-3-methylimidazolium chloride modified carbon paste electrode for voltammetric detection of pethidine in the presence morphine and olanzapine

Ultrasensitive functionalized CeO2/ZnO nanocomposite sensor for determination of a prohibited narcotic in sports pethidine hydrochloride

The extraordinary features of cerium oxide (CeO₂) and zinc oxide (ZnO) nanostructures have encouraged substantial attention to those nanocomposites as probable electroactive complexes for sensing and biosensing purposes. In this study, an advanced novel factionalized CeO₂/ZnO nanocomposite-aluminum wire membrane sensor was designed to assess pethidine hydrochloride (PTD) in commercial injection samples. Pethidine-reineckate (PTD-RK) was formed by mixing pethidine hydrochloride and ammonium reineckate (ARK) in the presence of polymeric matrix (polyvinyl chloride) and o-nitrophenyl octyl ether as a fluidizing agent. The functionalized nanocomposite sensor displayed a fast dynamic response and wide linearity for the detection of PTD. It also revealed excellent selectivity and sensitivity, high accuracy, and precision for the determination and quantification of PTD when compared with the unmodified sensor PTD-RK. The guidelines of analytical methodology requirements were obeyed to improve the suitability and validity of the suggested potentiometric system according to several criteria. The developed potentiometric system was suitable for the determination of PTD in bulk powder and commercial products.

Dual-emission ratiometric fluorescent probe based on N-doped CQDs@UiO-66/PVA nanocomposite hydrogel for quantification of pethidine in human plasma

A synchronous fluorescence spectroscopy (SFS) sensor for pethidine detection is described based on UiO-66 metal-organic frameworks (MOFs) modified with N-doped carbon quantum dots (N-CQDs) embedded in hydrogel nanocomposites. Benefitting from the inovative  design of the doping method in the carbonaceous structure, N-CQDs were successfully deposited in the pores of the UiO-66 network. Then, N-CQDs were employed as a sensitive segment toward the target molecules. UiO-66 was used for sensitive and selective sensing of the bonding interactions between N-CQDs and pethidine so that the electron transfer process from UiO-66 to the pethidine-N-CQD complex results in quenching the SFS intensity of UiO-66. To embed the stable and suitable sensing interface for pethidine assessment, the designed nanomaterial was inserted into the hydrogel network. This nanocomposite hydrogel showed two well-resolved emission peaks at 300 nm and 350 nm under ∆λ = 70, which corresponded to N-CQDs and UiO-66, respectively. The SFS sensing platform was employed for ratiometric detection of pethidine with a low limit of detection of 0.002 μg mL^-1 over a wide concentration range from 0.005 to 1.0 μg mL^-1. The accurate monitoring of pethidine with a good recovery of 90.8-101.5% indicated their independency from matrix effects for pethidine detection in human plasma being a complicated biological matrix. Scheme 1. General procedure for synthesizing N-CQDs@UiO-66/PVA hydrogel-based nanoprobe and its application for pethidine determination.