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The a Chemical structure of tested organophosphorus compounds: glyphosate, glufosinate, aminomethylphosphonic acid (AMPA), and chlorpyrifos. b Representative amperometric response of LIG-Cu electrodes in PBS (pH 7.2) at a polarization potential of 100 mV (rolling average, n = 5). Black arrows represent injections of each one of the organophosphorus compounds to the electrochemical cell. c Calibration curve of LIG-Cu electrodes in the presence of different organophosphorus compounds. Error bars represent standard error (n ≥ 3) d Performance parameters of the sensor. Same letters represent groups with no significant difference for each variable
Source publication
Organophosphorus pesticides are widely used in industrial agriculture and have been associated with water pollution and negative impacts on local ecosystems and communities. There is a need for testing technologies to detect the presence of pesticide residues in water sources, especially in developing countries where access to standard laboratory m...
Citations
... The most commonly used electrochemical techniques employed for the detection of glyphosate are amperometry, cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), all of which use different types of electrodes, such as carbon paste (CPE) [21], graphite pencil (PGE) [22], glassy carbon [23], gold [24,25], copper [26,27], carbon [21,22], mercury [28], and platinum [29]. In order to increase the sensitivity and selectivity for Gly detection in real samples, electrodes have been modified with different electroactive materials, such as graphene and graphene oxides [30][31][32], single and multi-walled carbon nanotubes (SWCNT, MWCNT) [23,33], copper or copper oxide (CuO) [26,[34][35][36][37], copper phthalocyanine [38,39], and molecularly imprinted polymers (MIP) [40][41][42][43][44][45]. ...
This study addresses the necessity to monitor the presence of glyphosate (Gly) in waters, highlighting the need for on-site detection of Gly by using electrochemical sensors in environmental and agricultural monitoring programs. Two approaches were employed: (1) modification with graphene decorated with gold nanoparticles (AuNPs-Gr) and dispersed in either dimethylformamide (DMF) or a solution containing Nafion and isopropanol (NAF), and (2) molecularly imprinted polymers (MIPs) based on polypyrrole (PPy) deposited on gold SPEs (AuSPE). Electrochemical characterization revealed that sensors made of AuNPs-Gr/SPCE exhibited enhanced conductivity, larger active area, and improved charge transfer kinetics compared to unmodified SPEs and SPEs modified with graphene alone. However, the indirect detection mechanism of Gly via complex formation with metallic cations in AuNPs-Gr-based sensors introduces complexities and compromises sensitivity and selectivity. In contrast, MIPPy/AuSPE sensors demonstrated superior performance, offering enhanced reliability and sensitivity for Gly analysis. The MIPPy/AuSPE sensor allowed the detection of Gly concentrations as low as 5 ng/L, with excellent selectivity and reproducibility. Moreover, testing in real surface water samples from the Olt River in Romania showed recovery rates ranging from 90% to 99%, highlighting the effectiveness of the detection method. Future perspectives include expanding the investigation to monitor Gly decomposition in aquatic environments over time, providing insights into the decomposition’s long-term effects on water quality and ecosystem health, and modifying regulatory measures and agricultural practices for mitigating its impact. This research contributes to the development of robust and reliable electrochemical sensors for on-site monitoring of Glyphosate in environmental and agricultural settings.
... After the photothermal conversion of polyimide to LIG, the 3D-structured carbon material can be modified in multiple ways for applications in electroanalytical sensing. Examples of post-manufacture modification techniques for sensing applications include: (i) tuning interaction chemistry by controlling hydrophobicity 17 ; (ii) metallization with gold 18 , platinum 19 , copper 20,21 , or zinc oxide 22 ; (iii) modification with macrotetrolide antibiotics 23 or synthetic ionophores 24 ; or (iv) biofunctionalization with enzymes 19,25 , antibodies 26 , and aptamers 27 . Beyond sensor development, LIG has been extended for use in wearable electronics 28 , microfluidic analytical devices 29 , or cell culture assays 29 , for example. ...
Laser-inscribed graphene (LIG), initially developed for graphene supercapacitors, has found widespread use in sensor research and development, particularly as a platform for low-cost electrochemical sensing. However, batch-to-batch variation in LIG fabrication introduces uncertainty that cannot be adequately tracked during manufacturing process, limiting scalability. Therefore, there is an urgent need for robust quality control (QC) methodologies to identify and select similar and functional LIG electrodes for sensor fabrication. For the first time, we have developed a statistical workflow and an open-source hierarchical clustering tool for QC analysis in LIG electrode fabrication. The QC process was challenged with multi-operator cyclic voltammetry (CV) data for bare and metalized LIG. As a proof of concept, we employed the developed QC process for laboratory-scale manufacturing of LIG-based biosensors. The study demonstrates that our QC process can rapidly identify similar LIG electrodes from large batches (n ≥ 36) of electrodes, leading to a reduction in biosensor measurement variation by approximately 13% compared to the control group without QC. The statistical workflow and open-source code presented here provide a versatile toolkit for clustering analysis, opening a pathway toward scalable manufacturing of LIG electrodes in sensing. In addition, we establish a data repository for further study of LIG variation.
... Finally, we close this section with a selection of sensors for relevant, other types of analytes: Bahamon-Pinzon et al. created an affordable amperometric sensor for organophosphorus pesticide monitoring through deposition of copper nanoparticles on LIG. Over the course of 21 days, the authors found that the signal intensity was independent of storage time but remarked that sensor reproducibility was low (with n = 3) and that improvements in the manufacturing process were necessary [36]. To create a sensor for the antibiotic and environmental pollutant chloramphenicol, Chang et al. decorated an LIG electrode with TiO 2 nanoparticles dispersed in carboxymethylcellulose and also added silver nanoparticles [37]. ...
Laser-induced graphene (LIG) has received much attention in recent years as a possible transducer material for electroanalytical sensors. Its simplicity of fabrication and good electrochemical performance are typically highlighted. However, we found that unmodified and untreated LIG electrodes had a limited shelf-life for certain electroanalytical applications, likely due to the adsorption of adventitious hydrocarbons from the storage environment. Electrode responses did not change immediately after exposure to ambient conditions but over longer periods of time, probably due to the immense specific surface area of the LIG material. LIG shelf-life is seldomly discussed prominently in the literature, yet overall trends for solutions to this challenge can be identified. Such findings from the literature regarding the long-term storage stability of LIG electrodes, pure and modified, are discussed here along with explanations for likely protective mechanisms. Specifically, applying a protective coating on LIG electrodes after manufacture is possibly the easiest method to preserve electrode functionality and should be identified as a trend for well-performing LIG electrodes in the future. Furthermore, suggested influences of the accompanying LIG microstructure/morphology on electrode characteristics are evaluated.
... Electrocatalytic performance of the PCE modified with CuONPs/Cdot(N) nanohybrid compared to other electrodes modified with different species[52][53][54][55] ...
This work describes the synthesis, characterization, and application of nanoneedle-shaped CuONPS/Cdot(N) nanostructures obtained by direct reaction between Cu(NO3)2 and nitrogen-doped carbon quantum dots (Cdot(N)). The CDot(N) obtained from oleylamine using the electrochemical technique of chronoamperometry was used as catalysts and directing agents in synthesizing CuONPS/Cdot(N) nanostructures. The CuONPS/Cdot(N) nanostructures were characterized using transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet spectroscopy (UV–Vis), infrared spectroscopy (FTIR), and electrochemical techniques. HR-TEM and XPS analysis has shown that CuONPS/Cdot(N) nanostructures are constituted for both CuO and Cu2O nanospecies. The printed carbon electrode was modified with CuONPS/Cdot(N) nanostructures. It was used to determine the pesticide glyphosate in PBS, pH 5.5, at a potential of E = − 0.02 V, using the differential pulse voltammetry technique with a detection limit of 11.6 nMol L⁻¹. The printed carbon electrode was modified with CuNPS/Cdot(N) nanostructures and was also used to determine pesticides in real water samples with good performance.
Graphical Abstract
This work presents the synthesis and characterization of an innovative F, S-doped Carbon dots/ CuONPs hybrid nanostructure obtained by a direct mixture between F, S-doped Carbon dots obtained electrochemically and...
The present article critically and comprehensively reviews the most recent reports on smart sensors for determining glyphosate (GLP), an active agent of GLP-based herbicides (GBHs) traditionally used in agriculture over the past decades. Commercialized in 1974, GBHs have now reached 350 million hectares of crops in over 140 countries with an annual turnover of 11 billion USD worldwide. However, rolling exploitation of GLP and GBHs in the last decades has led to environmental pollution, animal intoxication, bacterial resistance, and sustained occupational exposure of the herbicide of farm and companies' workers. Intoxication with these herbicides dysregulates the microbiome-gut-brain axis, cholinergic neurotransmission, and endocrine system, causing paralytic ileus, hyperkalemia, oliguria, pulmonary edema, and cardiogenic shock. Precision agriculture, i.e., an (information technology)-enhanced approach to crop management, including a site-specific determination of agrochemicals, derives from the benefits of smart materials (SMs), data science, and nanosensors. Those typically feature fluorescent molecularly imprinted polymers or immunochemical aptamer artificial receptors integrated with electrochemical transducers. Fabricated as portable or wearable lab-on-chips, smartphones, and soft robotics and connected with SM-based devices that provide machine learning algorithms and online databases, they integrate, process, analyze, and interpret massive amounts of spatiotemporal data in a user-friendly and decision-making manner. Exploited for the ultrasensitive determination of toxins, including GLP, they will become practical tools in farmlands and point-of-care testing. Expectedly, smart sensors can be used for personalized diagnostics, real-time water, food, soil, and air quality monitoring, site-specific herbicide management, and crop control.
