Microwave-prepared surface imprinted magnetic nanoparticles based electrochemical sensor for adsorption and determination of ketamine in sewage

Analysis of ketamine and norketamine in urine by automatic solid-phase extraction (SPE) and positive ion chemical ionization–gas chromatography–mass spectrometry (PCI–GC–MS)

Quantitative detection of ketamine, norketamine, and dehydronorketamine in urine using chemical derivatization followed by gas chromatography–mass spectrometry

Characterization of an electrochemical mercury sensor using alternating current, cyclic, square wave and differential pulse voltammetry

Electrochemical magnetic imprinted sensor based on MWCNTs@CS/CTABr surfactant composites for sensitive sensing of diethylstilbestrol

Increasing the release of antibiotics in particular tetracycline in the environment is become one of the most concerns that threat human and animals' health. Regarding their low cost, sensitivity, portability, electrochemical sensors have received attention for tetracycline monitoring. With a nanostructure, diverse active functional sites, and good conductivity, green nanoparticles are considered now as an attractive material for sensors design. The objective of the present paper is then the design of electrochemical sensor functionalized with green nanoparticles based on gum Arabic for tetracycline detection. The green nanoparticles are synthesized by direct reduction of silver nanoparticle with gum Arabic polymer. The intrinsic properties of the obtained nanoparticles are examined using different techniques namely UV–Vis absorption (UV), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric TGA. To follow up, the sensor modification as well as tetracycline detection, cyclic voltammetry (CV) and square wave voltammetry are carried out. Correlation between the different results have demonstrated good dispersion and homogeneity of green nanoparticles, with good applicability in electrochemical measurements. In fact, the sensor has demonstrated wide concentrations range from 0.1 to 1250 nM with a limit of detection in the order of 0.056 nM, lower than those reported in the literature. The selectivity test, investigated against a various interfering with similar structure to tetracycline, have proven a good discrimination between all molecules. In addition, the sensor was successfully applied to real samples, and the found recovery rates are ranging from 90.4% to 106.9%. The obtained results confirm that green nanoparticles based on gum Arabic could commercially be viable for next generation of electrochemical sensor for tetracycline detection, and also could be applied for the detection of the variety of pharmaceutical pollutants in the environment.

In this study, we have developed a label-free immunosensor with the variation of resonance frequency (Δf) of a quartz crystal microbalance (QCM) as readout signal for ultrasensitive detection of Ketamine (KT). An optimized strategy for immobilization of KT antibody on the surface of the QCM chip was implemented via the self-assembly modification of 3-mercaptopropionic acid, and then activated with 1-ethyl-3- (3-dimethylaminoprophl) carbodiimide and n-hydroxysuccinimide. The specific affinity between the antibody and the antigen ensured a selective response toward KT. The Δf linearly related to the concentration of KT in the range of 1 to 40 pg/mL, with a detection limit of 0.86 pg/mL (S/N = 3). The obtained immunosensor was applied to detect the KT in spiked human urine without any pretreatment but dilution with recoveries from 91.8% to 108%. The developed sensor is promising to perform the portable or on-spot KT detection in clinic or forensic cases.

As one of the most prevalent drugs, ketamine (KT) presents a significant social risk, making the development of a specific and ultrasensitive detection tool essential. Herein, the molecular dynamics (MD) simulation calculation-based molecularly imprinted polymer (MIP) with excellent recognition capability and the ZnO-CuO p-n heterojunction with efficient charge separation were prepared to fabricate a novel molecularly imprinted photoelectrochemical (MIP-PEC) sensor for the specific and ultrasensitive detection of KT. Impressively, compared with traditional MIP preparation methods that suffer from limited selectivity and inefficient trial-and-error component screening, MD simulation calculations enable the rational design of highly selective MIP, reducing costs and enhancing efficiency. Specifically, the binding energy of KT with functional monomers and cross-linkers, along with the solvation energy of solvents, were analyzed by MD simulation calculations, ultimately identifying the methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), and acetonitrile (ACN) as the optimal components to build MIP with precisely recognized cavities, which effectively improved the detection selectivity of the designed sensor. Furthermore, the ZnO-CuO p-n heterojunction with a precisely matched band effectively reduced the recombination rate of carriers, enhancing photoelectric response and stability. As a result, the constructed MIP-PEC sensor successfully achieved a specific and ultrasensitive assay of KT with a low detection limit down to 0.746 nM, an imprinting factor (IF) of 8.75, and a selectivity factor (SF) of 4.70, surpassing previous reports and enabling successful application in urine, saliva, and wastewater samples. This study provides a distinctly specific and ultrasensitive analytical platform for the assay of illegal drugs in the field of social security.

Determination of ketamine, methamphetamine and 3,4-methylenedioxymethamphetamine in human hair by flash evaporation-gas chromatography/mass spectrometry

Ketamine (KET) analogs are increasingly emerging as new psychoactive substances (NPS). The present report describes the first detection of the KET analog, 2-fluorodeschloroketamine (2F-DCK), in influent samples collected from nine wastewater treatment plants in seven major Chinese cities from 2018 to 2020 by wastewater-based epidemiology (WBE). An analytical method based on solid-phase extraction and subsequent gas chromatography-mass spectrometry was developed for the detection of 2F-DCK and KET. The stability experiments showed that 2F-DCK and KET remained stable in wastewater for 15 days at room and frozen temperatures, and at two pH values (pH = 7 and pH = 2), with residue amounts between 90% and 110%. KET was detected in all samples, whereas 2F-DCK was detected in only four samples: from Guangzhou in 2018, Shenzhen in 2019, and Quanzhou and Nanning in 2020, indicating that 2F-DCK has been used as early as 2018 in China. The renal clearance of 2F-DCK was predicted based on the quantitative structure-pharmacokinetic relationship model, which was used to calculate an excretion factor of 3.7. The 2F-DCK consumption in four cities ranged from 3.71 ± 0.05 to 55 ± 0.09 mg/day/1000 inh, and KET ranged from 1.3 ± 0.04 to 76.5 ± 4.63 mg/day/1000 inh. This is the first study to investigate 2F-DCK by WBE, which provides relevant real-time data on the growth of NPS use, as well as useful information for the government to develop new policies.

A terpolymer poly(aniline‐co‐o‐anisidine‐co‐o‐toluidine)/graphene oxide nanocomposite with a common abbreviation [PANI‐co‐PoAN‐co‐PoT/GO 1‐5 ] was synthesized by the well‐known in situ oxidative polymerization process with ultrasonic assistance. The morphological characteristics were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Moreover, the complete performance was studied by Fourier transform infrared spectra (FTIR), X‐ray diffraction (XRD), Thermogravimetric analysis (TGA), and electrical conductivity measurements. All nanocomposites displayed a maximum composite degradation temperature (CDT max ) in the range of 295.6‐322.8 °C, which is higher than that shown for the pure terpolymer (295.4 °C). The conductivities of the pure PANI‐co‐PoAN‐co‐PoT and PANI‐co‐PoAN‐co‐PoT/GO 1‐5 nanocomposites display conductive behavior. An electrochemical sensor comprising the [PANI‐co‐PoAN‐co‐PoT/GO] nanocomposite and Au nanoparticles was successfully coated onto a gold electrode [AuNPs/PANI‐co‐PoAN‐co‐PoT/GO/Au] through an electrochemical process and was utilized to detect sunset yellow (SY). The electrochemical behavior of the modified electrochemical sensor towards the oxidation of SY was examined by cyclic voltammetry (CV) and square wave voltammetry (SWV). SWV resulted in a linear calibration curve for SY on AuNPs/PANI‐co‐PoAN‐co‐PoT/GO/Au over the range of (5 μM‐500 μM), and the limit of detection was estimated to be 0.0142 μM. These results suggest that the obtained AuNPs/PANI‐co‐PoAN‐co‐PoT/GO/Au was able to detect SY with excellent stability, good selectivity, low detection limit and high sensitivity.

ABSTRACTAtrazine is a pesticide that belongs to the class of chlorotriazine and has been proven to cause severe damage to the human endocrine system in case of ingestion. With its harmful effect on animals, plants, and the environment, there is a need for the development of sensor platforms that will be effective in detecting atrazine's presence in an aquatic environment. Metal–organic frameworks (MOFs), as a class of very ordered crystalline materials, have been of great interest because of their potential applications in electrochemical sensors based on distinct chemical and physical properties such as extremely high porosity, large surface area, and easily modifiable structural features. Bimetallic systems, in particular, provide MOFs with improved functionalities required for efficient electrochemical sensing. A bimetallic CuNi MOF–based binary nanocomposite with nitrogen‐doped 3‐dimensional rGO (N‐3DrGO) was designed and was used to fabricate a sensor on the indium tin oxide (ITO) electrode. Powder X‐ray diffraction (PXRD), Fourier transform infrared (FTIR), Raman spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and X‐ray photoelectron spectroscopy (XPS) techniques were employed for the characterization of CuNi‐MOF/N‐3DrGO. Further, in atrazine sensing, cyclic voltammetry (CV) analysis and square wave voltammetry (SWV) showed a decrease in current due to the blocking of electron transfer between the electrode and electrolyte interface. Later, SWV analysis showed our designed sensor can sense at a very wide range of 0.5 to 150 ppb with a limit of detection (LOD) of 0.18 ppb. This sensor also exhibited superior selectivity in the presence of other interfering ions and pesticides, stability for up to 5 weeks, and reproducibility. Lastly, a real‐time sensing approach was performed by taking water, which showed an average recovery of 99.385%.

A novel electrochemical sensor was constructed for sensitive and selective determination of carbamazepine (CBZ). First trimetallic Au core AgPd shell nanoparticles (Au@AgPdNPs) with dendritic morphology were synthesized by a facile method and then the nanocomposite of Au@AgPdNPs, macrocyclic β-cyclodextrin and butyl-3-metylimidazolium bis (trifluorometylsulfonyl) imide ionic liquid was prepared to modify a glassy carbon electrode. The formation of Au@AgPdNPs was characterized using transmission electron microscopy (TEM) and energy dispersion spectroscopy (EDS). The surface morphology of the modified electrode was characterized by scanning electron microscopy (SEM). Electrochemical methods including cyclic voltammetry (CV) and square wave voltammetry (SWV) were used to study the electrochemical behavior of CBZ. The effect of several relevant operating parameters was investigated and optimized. Under the optimized experimental conditions, the calibration curve was linear within the concentration ranges of 0.5 μM to 90 μM of CBZ with a limit of detection (LOD) of 0.089 μM. Also, the reproducibility, repeatability and stability of the constructed electrochemical sensor, were all found to be satisfactory. Finally, the proposed sensor was successfully employed for the direct determination of CBZ in in real samples.

Straightforward screening of ketamine in forensic samples using voltammetry with screen-printed carbon graphite electrodes.

Determination of ketamine and norketamine in hair by micropulverized extraction and liquid chromatography–high resolution mass spectrometry

The present work reports for the first time the design of an electrochemical sensor functionalized with green nanoparticles based on Hyphaene thebaica for amoxicillin quantification. Based on a simple one‐pot bio‐reduction reaction, lead oxide PbO coated with Hyphaene thebaica was synthesized. Ultraviolet‐visible spectroscopy (UV), fourier transform infrared (FITR), transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used to control optical, structural, morphological, and physicochemical properties of the elaborated nanoparticles. Results demonstrated a good dispersion with a spherical morphology, which is in the order 8 nm. Regarding the good properties of nanoparticles, they are integrated to design an electrochemical sensor for amoxicillin detection. Cyclic voltammetry and square wave voltammetry were used to follow up the sensor modification and the electrochemical sensor response versus different amoxicillin concentrations. Under optimal conditions, the electrochemical sensor modified with the nanoparticles in question provides a linear detection in the range 50–10000 nM, with a detection limit of 0.105 nM. The proposed sensor also exhibits good sensitivity and selectivity against several antibiotic analogues and has been successfully applied to real samples. Aside from its power in several fields including antibacterial, antifungal, enzyme‐inhibiting and antioxidant, green nanoparticles based on Hyphaene thebaica have demonstrated an effectiveness as a sensor for the electrochemical detection of amoxicillin, highlighting the possibility of adopting these sensors as routine test for the environment monitoring.