Chemosensors

23 pages, 1146 KB

Open AccessReview

Real-Time Detection of Heavy Metals and Some Other Pollutants in Wastewater Using Chemical Sensors: A Strategy to Limit the Spread of Antibiotic-Resistant Bacteria

by Liliana Anchidin-Norocel, Anca Bosancu, Oana C. Iatcu, Andrei Lobiuc and Mihai Covasa

Chemosensors 2025, 13(9), 352; https://doi.org/10.3390/chemosensors13090352 (registering DOI) - 12 Sep 2025

Abstract

The increasing presence of heavy metals in wastewater is a growing environmental and public health concern, particularly due to their role in promoting the spread of antibiotic-resistant bacteria (ARB) through co-selection mechanisms. This review explores recent advances in real-time detection of heavy metals [...] Read more.

The increasing presence of heavy metals in wastewater is a growing environmental and public health concern, particularly due to their role in promoting the spread of antibiotic-resistant bacteria (ARB) through co-selection mechanisms. This review explores recent advances in real-time detection of heavy metals and some other pollutants using chemical sensors as a strategic tool to limit ARB proliferation. It provides an overview of sensor types, including electrochemical, optical, biosensors, and molecularly imprinted polymer (MIP) sensors, and assesses their suitability for monitoring pollutants in complex wastewater matrices. Emphasis is placed on the integration of these technologies with Internet of Things (IoT) platforms, portable and autonomous systems, and data-driven approaches for multi-metal detection, selectivity enhancement, and predictive analysis. The review also discusses current challenges such as sensor stability, interference, and cost-efficiency, and outlines future directions in real-time environmental monitoring and antibiotic resistance control. Overall, chemical sensor-based monitoring offers a promising, scalable solution for safeguarding ecosystems and public health in the face of growing antimicrobial resistance. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

► Show Figures

Figure 1

35 pages, 853 KB

Open AccessReview

Recent Advances in Benzodiazepine Electroanalysis

by Mihaela-Carmen Cheregi, Emilia-Elena Iorgulescu, Mircea-Alexandru Comănescu, Iulia Gabriela David and Adelaida Sorana Trifu

Chemosensors 2025, 13(9), 351; https://doi.org/10.3390/chemosensors13090351 - 12 Sep 2025

Abstract

Benzodiazepines are psychoactive drugs with wide clinical applications. Unfortunately, due to their sedative effects, benzodiazepines are frequently used as date rape drugs or in drug-facilitated crimes. Considering the electroactive nature of benzodiazepines and the unique advantages of electrochemical techniques, this review presents a [...] Read more.

Benzodiazepines are psychoactive drugs with wide clinical applications. Unfortunately, due to their sedative effects, benzodiazepines are frequently used as date rape drugs or in drug-facilitated crimes. Considering the electroactive nature of benzodiazepines and the unique advantages of electrochemical techniques, this review presents a critical discussion of the state of the art of benzodiazepine electroanalysis. Aspects related to sample preparation as well as electrodes (from mercury electrodes to bare or modified solid electrodes and to disposable sensors) and techniques (mainly voltammetry) used for the quantification of benzodiazepines in different matrices (pharmaceuticals, body fluids, alcoholic and soft drinks) were discussed. Considering the actual achievements in the field, some general suggestions for possible further research were given. Full article

(This article belongs to the Section Applied Chemical Sensors)

13 pages, 3145 KB

Open AccessArticle

Noble Metal-Decorated In₂O₃ for NO₂ Gas Sensor: An Experimental and DFT Study

by Parameswari Raju, Jafetra Rambeloson, Dimitris E. Ioannou, Abhishek Motayed and Qiliang Li

Chemosensors 2025, 13(9), 350; https://doi.org/10.3390/chemosensors13090350 - 11 Sep 2025

Abstract

Indium oxide-based gas sensors have been proven to be a promising material for detecting nitrogen dioxide (NO₂) gas because of its wide bandgap and stability. In this paper, the enhancement mechanism for the sensitivity of indium oxide NO₂ gas sensors [...] Read more.

Indium oxide-based gas sensors have been proven to be a promising material for detecting nitrogen dioxide (NO₂) gas because of its wide bandgap and stability. In this paper, the enhancement mechanism for the sensitivity of indium oxide NO₂ gas sensors was systematically investigated using density functional theory (DFT) calculations and experimental validation with noble metals like Au, Ag, Pt, Pd, and Cu. We have fabricated a GaN nanowire-based NO₂ gas sensor functionalized with In₂O₃ and decorated with noble metals using a standard fabrication technique. Experimental tests showed that Au/In₂O₃ sensors exhibited the highest response of 38.9% followed by bare In₂O₃ with 10% for 10 ppm NO₂ at room temperature. The sensing properties were mainly attributed to a spillover effect or catalytic performance of Au with In₂O₃. The adsorption energies, charge transfers, and band gap confirm the enhanced sensing capability of Au-decorated Indium oxide for a NO₂ gas sensor. Full article

(This article belongs to the Special Issue Nanomaterial-Based Sensors: Design, Development and Applications)

► Show Figures

Figure 1

18 pages, 1503 KB

Open AccessArticle

Investigation of Distinct Odor Profiles of Blood over Time Using Chemometrics and Detection Canine Response

by Fantasia Whaley, Valerie Albizu, Jordi Cruz, Rushali Dargan and Lauryn DeGreeff

Chemosensors 2025, 13(9), 349; https://doi.org/10.3390/chemosensors13090349 - 11 Sep 2025

Abstract

The detection of blood by human remains detection (HRD) canines and blood detection dogs (BDDs) is crucial to both search and rescue (SAR) and crime scene investigation. They can be used to find both missing persons and to detect otherwise undetectable blood evidence [...] Read more.

The detection of blood by human remains detection (HRD) canines and blood detection dogs (BDDs) is crucial to both search and rescue (SAR) and crime scene investigation. They can be used to find both missing persons and to detect otherwise undetectable blood evidence at crime scenes. An added level of difficulty with training occurs as blood volatile organic compounds (VOCs) are drastically affected by time. Previous studies have shown this, with a focus on a longer timescale (weeks/months). Little data exists on the changes in the first 48 h, the most crucial time in SAR, something this study aims to rectify. Data was collected using headspace solid-phase microextraction/gas chromatography–mass spectrometry, which was then analyzed using chemometrics and confirmed with canine trials. The results of the laboratory analysis indicated that there were multiple, distinct odor profiles between the 1 h and 2-week time windows—namely, the fresh, intermediate, and aged stages of decomposition. The noted changes in the odor profiles were validated with HRD canine trials. Canines had difficulty detecting the fresh blood (1–2 h old) and had the greatest detection rate for the aged blood (34–36 h old). Both the chemical analysis and canine behavior data displayed a clear change in the odor profile within the first 48 h. This information will assist SAR, HRD, and BBD training to ensure they train on all distinct odor profiles. Full article

(This article belongs to the Special Issue Detection of Volatile Organic Compounds in Complex Mixtures)

► Show Figures

Figure 1

15 pages, 9429 KB

Open AccessArticle

Nanoparticle-Coated Optical Hydrogen Sensor for Early Gas Detection of Lithium-Ion Battery Failure

by Leonard Kropkowski, Ahmad Abdalwareth, Christoff Brüdigam, Martin Angelmahr and Wolfgang Schade

Chemosensors 2025, 13(9), 348; https://doi.org/10.3390/chemosensors13090348 - 11 Sep 2025

Abstract

This research investigates the use of a fiber optic sensor for detecting hydrogen gas during a thermal runaway of lithium-ion batteries (LIBs). Timely detection of thermal runaway in LIBs, particularly in storage and logistics, is crucial for effective safety management and preventing the [...] Read more.

This research investigates the use of a fiber optic sensor for detecting hydrogen gas during a thermal runaway of lithium-ion batteries (LIBs). Timely detection of thermal runaway in LIBs, particularly in storage and logistics, is crucial for effective safety management and preventing the escalation of incidents to adjacent cells. The sensors employed in this study utilize fiber Bragg grating (FBG) technology. The FBG sensors are coated with palladium nanoparticles, enabling the detection of hydrogen concentrations up to 5%. In abuse tests, the sensors successfully identified hydrogen emissions. Cross-sensitivity effects were observed during a secondary test and were thoroughly investigated. These interferences were found to be primarily caused by carbon monoxide (CO), a common byproduct of battery venting. While the presence of CO can interfere with hydrogen detection, both signals remain independently valuable as indicators of cell malfunction. This dual-response behavior enhances the robustness of fault detection under real-world battery failure scenarios. Full article

(This article belongs to the Section Optical Chemical Sensors)

► Show Figures

Figure 1

21 pages, 588 KB

Open AccessReview

Gas Sensing for Poultry Farm Air Quality Monitoring to Enhance Welfare and Sustainability

by Ibn e Abbas and Elisabetta Comini

Chemosensors 2025, 13(9), 347; https://doi.org/10.3390/chemosensors13090347 - 10 Sep 2025

Abstract

This investigation highlights the importance of adopting ethical and sustainable practices in chicken farming, in response to the increasing global demand for poultry products driven by the expanding world population. How ambient gases, such as hydrogen sulfide (

H_{2} S

), nitrous [...] Read more.

This investigation highlights the importance of adopting ethical and sustainable practices in chicken farming, in response to the increasing global demand for poultry products driven by the expanding world population. How ambient gases, such as hydrogen sulfide (

H_{2} S

), nitrous oxide (

N_{2} O

), ammonia (

N H_{3}

), carbon dioxide (

C O_{2}

), and methane (

C H_{4}

), affect the welfare of farm workers and poultry is investigated. The use of various gas sensor technologies is crucial for effective management and monitoring of these gases. The research emphasizes the vital importance of precise gas concentration measurements in mitigating environmental impact. It is noteworthy that there is a closely intertwined relationship between

C O_{2}

levels and chicken health, requiring vigilant monitoring and care. There are potential risks associated with

N H_{3}

exposure, and waste management and ventilation practices are necessary. Furthermore, the contribution of

C H_{4}

sensors to environmental sustainability and safety is addressed. The review also examines

H_{2} S

emissions, providing mitigation strategies to safeguard avian health. This study identifies an important gap between the limited use of commercially available Metal Oxide Semiconductor (MOS) sensors in the commercial Internet of Things (IoT) systems for poultry farms and their potential to detect a wider range of chemical gases. The pivotal role played by gas sensors in these sustainable efforts is highlighted. Full article

(This article belongs to the Special Issue Recent Advances in Low-Cost Chemical Sensor Technologies for Environmental Monitoring Applications)

► Show Figures

Figure 1

19 pages, 4940 KB

Open AccessArticle

Unraveling Seasonal Dynamics of Dissolved Organic Matter in Agricultural Ditches Using UV-Vis Absorption and Excitation–Emission Matrix (EEM) Fluorescence Spectroscopy

by Keyan Li, Jinfeng Ge, Qiaozhuan Hu, Wenrui Yao, Xiaoli Fu, Chao Ma and Yulin Qi

Chemosensors 2025, 13(9), 346; https://doi.org/10.3390/chemosensors13090346 - 10 Sep 2025

Viewed by 61

Abstract

Seasonal dynamics of dissolved organic matter (DOM) in agricultural ditches significantly impact carbon cycling and water quality in connected rivers. This study aimed to characterize seasonal variations in DOM composition and dynamics within hierarchical agricultural ditch systems in Tianjin, northern China. Surface water [...] Read more.

Seasonal dynamics of dissolved organic matter (DOM) in agricultural ditches significantly impact carbon cycling and water quality in connected rivers. This study aimed to characterize seasonal variations in DOM composition and dynamics within hierarchical agricultural ditch systems in Tianjin, northern China. Surface water samples were collected from river channels, main ditches, branch ditches, lateral ditches, and field ditches during wet (June 2021) and dry (December 2021) seasons. DOM characteristics were analyzed using dissolved organic carbon (DOC) quantification, ultraviolet-visible (UV-Vis) absorption spectroscopy, and three-dimensional excitation–emission matrix spectroscopy (3D-EEMs) coupled with parallel factor analysis (PARAFAC). The concentration of DOC in ditch surface water exhibited significant seasonal variations, with significantly higher levels observed during the wet season (Huangzhuang: 6.72 ± 0.7 mg/L; Weixing: 13.15 ± 3.1 mg/L) compared to the dry season (Huangzhuang: 5.93 ± 0.3 mg/L; Weixing: 9.35 ± 2.6 mg/L). Both UV-Vis spectral and EEM-PARAFAC analysis revealed that DOM in ditch systems was predominantly composed of fulvic-like and tryptophan-like components, representing the portion of organic matter in water bodies that is highly biologically active, highly mobile, relatively “fresh”, or “not fully humified”. PARAFAC identified microbial humic-like (C1: wet season 40.36%, dry season 34.42%) and protein-like (C3: wet season 40.3%, dry season 49.87%) components as dominant. DOM sources were influenced by dual inputs from terrestrial and autochthonous origins during the wet season, while primarily deriving from autochthonous sources in the dry season. This study elucidates the advances of spectroscopic techniques in deciphering the composition, sources, and influencing factors of DOM in aquatic systems. The findings support implementing riparian buffer strips and optimized fertilizer management to mitigate seasonal peaks of bioavailable DOM in agricultural ditch systems. Full article

(This article belongs to the Special Issue Spectroscopic Techniques for Chemical Analysis)

► Show Figures

Figure 1

44 pages, 1983 KB

Open AccessReview

Next-Generation Chemical Sensors: The Convergence of Nanomaterials, Advanced Characterization, and Real-World Applications

by Abniel Machín and Francisco Márquez

Chemosensors 2025, 13(9), 345; https://doi.org/10.3390/chemosensors13090345 - 8 Sep 2025

Viewed by 139

Abstract

Chemical sensors have undergone transformative advances in recent years, driven by the convergence of nanomaterials, advanced fabrication strategies, and state-of-the-art characterization methods. This review emphasizes recent developments, with particular attention to progress achieved over the past decade, and highlights the role of the [...] Read more.

Chemical sensors have undergone transformative advances in recent years, driven by the convergence of nanomaterials, advanced fabrication strategies, and state-of-the-art characterization methods. This review emphasizes recent developments, with particular attention to progress achieved over the past decade, and highlights the role of the United States as a major driver of global innovation in the field. Nanomaterials such as graphene derivatives, MXenes, carbon nanotubes, metal–organic frameworks (MOFs), and hybrid composites have enabled unprecedented analytical performance. Representative studies report detection limits down to the parts-per-billion (ppb) and even parts-per-trillion (ppt) level, with linear ranges typically spanning 10–500 ppb for volatile organic compounds (VOCs) and 0.1–100 μM for biomolecules. Response and recovery times are often below 10–30 s, while reproducibility frequently exceeds 90% across multiple sensing cycles. Stability has been demonstrated in platforms capable of continuous operation for weeks to months without significant drift. In parallel, additive manufacturing, device miniaturization, and flexible electronics have facilitated the integration of sensors into wearable, stretchable, and implantable platforms, extending their applications in healthcare diagnostics, environmental monitoring, food safety, and industrial process control. Advanced characterization techniques, including in situ Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS, Atomic Force Microscopy (AFM), and high-resolution electron microscopy, have elucidated interfacial charge-transfer mechanisms, guiding rational material design and improved selectivity. Despite these achievements, challenges remain in terms of scalability, reproducibility of nanomaterial synthesis, long-term stability, and regulatory validation. Data privacy and cybersecurity also emerge as critical issues for IoT-integrated sensing networks. Looking forward, promising future directions include the integration of artificial intelligence and machine learning for real-time data interpretation, the development of biodegradable and eco-friendly materials, and the convergence of multidisciplinary approaches to ensure robust, sustainable, and socially responsible sensing platforms. Overall, nanomaterial-enabled chemical sensors are poised to become indispensable tools for advancing public health, environmental sustainability, and industrial innovation, offering a pathway toward intelligent and adaptive sensing systems. Full article

(This article belongs to the Special Issue Revolutionizing the Future: Cutting-Edge Chemical Sensor Technologies in the USA)

► Show Figures

Graphical abstract

47 pages, 3847 KB

Open AccessReview

Photoelectrochemical Aptasensors for Biosensing: A Review

by Gang Xiao, Jiazheng Li, Boxiang Zhao and Zhao Yue

Chemosensors 2025, 13(9), 344; https://doi.org/10.3390/chemosensors13090344 - 8 Sep 2025

Viewed by 332

Abstract

Biodetection, the basis of many biotechnologies, has rapidly developed in recent years. Among various biodetection methods, the photoelectrochemical (PEC) sensor is an emerging analytical method and has been applied in biodetection widely because of its high sensitivity, low cost, expandability into multichannel sensor [...] Read more.

Biodetection, the basis of many biotechnologies, has rapidly developed in recent years. Among various biodetection methods, the photoelectrochemical (PEC) sensor is an emerging analytical method and has been applied in biodetection widely because of its high sensitivity, low cost, expandability into multichannel sensor arrays, and many other superior properties. Unlike conventional electrochemical aptasensors, the PEC aptasensor uses light as the excitation and an electrical photocurrent as the readout, which separates the stimulus from the measurement and reduces the excitation-related background. By modulating the light and demodulating the current, the PEC aptasensor improves the signal-to-noise ratio and lowers the limit of detection in complex matrices. Compared with optical aptasensors, the PEC aptasensor relies on simple light sources and electrodes rather than bulky imaging optics, enabling easier miniaturization and light-addressed multiplexed arrays. Therefore, aptamer-based PEC aptasensors have become a new hotspot in the field of biodetection. In this review, the development history of PEC aptasensors was presented. Then, this paper focuses on the photoactive nanomaterials, aptamers as sensing films, and sensing strategies of PEC aptasensors. The applications of PEC aptasensors in biodetection were also discussed. Finally, current challenges are discussed and opportunities in the future are prospected. Full article

(This article belongs to the Special Issue Functional Nanomaterial-Based Electrochemical Sensors)

► Show Figures

Figure 1

15 pages, 3450 KB

Open AccessArticle

High-Intensity In Situ Fluorescence Imaging of MicroRNA in Cells Based on Y-Shaped Cascade Assembly

by Yan Liu, Xueqing Fan, Xinying Zhou, Zhiqi Zhang, Qi Yang, Rongjie Yang, Yingxue Li, Anran Zheng, Lianqun Zhou, Wei Zhang and Jinze Li

Chemosensors 2025, 13(9), 343; https://doi.org/10.3390/chemosensors13090343 - 6 Sep 2025

Viewed by 1116

Abstract

MicroRNAs are closely associated with various physiological and pathological processes, making their in situ fluorescence imaging crucial for functional studies and disease diagnosis. Current methods for the in situ fluorescence imaging of microRNA predominantly rely on linear signal amplification, resulting in relatively weak [...] Read more.

MicroRNAs are closely associated with various physiological and pathological processes, making their in situ fluorescence imaging crucial for functional studies and disease diagnosis. Current methods for the in situ fluorescence imaging of microRNA predominantly rely on linear signal amplification, resulting in relatively weak imaging signals. This study introduces a Y-shaped cascade assembly (YCA) method for high-brightness microRNA imaging in cells. Triggered by target microRNA, catalytic hairpin assembly forms double-stranded DNA (H). Through annealing and hybridization, a Y-shaped structure (P) is created. These components assemble into DNA nanofluorescent particles with multiple FAM fluorophores, significantly amplifying fluorescence signals. Optimization experiments revealed that a 1:1 ratio of P to H and an assembly time of 60 min yielded the best results. Under these optimal conditions, the resulting fluorescent nanoparticles exhibited diameters of 664.133 nm, as observed by DLS. In Huh7 liver cancer cells, YCA generated DNA nanoparticles with a fluorescence intensity increase of 117.77%, triggered by target microRNA-21, producing high-intensity fluorescence images and enabling qualitative detection of microRNA-21. The YCA in situ imaging method offers excellent imaging quality and high efficiency, providing a robust and reliable analytical tool for the diagnosis and monitoring of microRNA-related diseases. Full article

(This article belongs to the Special Issue Advancements of Chemosensors and Biosensors in China—2nd Edition)

► Show Figures

Graphical abstract

16 pages, 4501 KB

Open AccessArticle

An Electrochemical Aptamer Sensor with ZIF-8 Loaded CuNPs Composites for Aflatoxin B₁ Determination

by Juncheng Chen, Caizhang Wu, Zhike Zhao and Ruihao Xue

Chemosensors 2025, 13(9), 342; https://doi.org/10.3390/chemosensors13090342 - 6 Sep 2025

Viewed by 193

Abstract

An electrochemical aptamer sensor for the sensitive detection of aflatoxin B₁ (AFB₁) in corn samples was developed using nanocomposites loaded with copper nanoparticles (CuNPs) on zeolitic imidazolate framework-8 (ZIF-8), which were modified on a glassy carbon electrode (GCE). The CuNPs@ZIF-8 [...] Read more.

An electrochemical aptamer sensor for the sensitive detection of aflatoxin B₁ (AFB₁) in corn samples was developed using nanocomposites loaded with copper nanoparticles (CuNPs) on zeolitic imidazolate framework-8 (ZIF-8), which were modified on a glassy carbon electrode (GCE). The CuNPs@ZIF-8 nanocomposites served as modifying materials for electrodes, exhibiting a high specific surface area and excellent compatibility with aptamers, thereby enhancing the electron transfer rate and increasing the aptamer loading and immobilization efficiency. The electrochemical properties before and after modification were investigated and validated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, while the sensor’s performance was analyzed through quantitative detection via differential pulse voltammetry (DPV). Furthermore, various conditions, including the volume of ZIF-8 dispersion, electrodeposition time of copper nanoparticles, aptamer concentration, and AFB₁ incubation time, were optimized. The results indicated that the sensor exhibited a wide linear range (10.0 to 1.0 × 10⁶ pg/mL), with a lower limit of detection (LOD) of 1.13 pg/mL under optimized conditions, outperforming other reported aptamer sensors. The spiked recoveries in corn samples ranged from 96.663% to 105.72%. In conclusion, this sensor presents a novel solution for low-cost and high-sensitivity detection of AFB₁. Full article

(This article belongs to the Section (Bio)chemical Sensing)

► Show Figures

Figure 1

16 pages, 2387 KB

Open AccessArticle

Simulation Study of the Effects of Solution Properties on Ion Separation Performance Using Microchip Electrophoresis

by Mingpeng Yang and Xiaolei Chen

Chemosensors 2025, 13(9), 341; https://doi.org/10.3390/chemosensors13090341 - 6 Sep 2025

Viewed by 255

Abstract

Microchip electrophoresis (ME) has been recognized as a promising analytical technique in life sciences, disease diagnostics, and environmental monitoring due to advantages such as minimal reagent consumption, rapid analysis, and compact size. While extensive efforts have been made to enhance ion analysis performance, [...] Read more.

Microchip electrophoresis (ME) has been recognized as a promising analytical technique in life sciences, disease diagnostics, and environmental monitoring due to advantages such as minimal reagent consumption, rapid analysis, and compact size. While extensive efforts have been made to enhance ion analysis performance, the influence of solution properties—such as zeta potential, diffusion coefficient, ionic charge, and dynamic viscosity—has not been fully explored. In this study, the influence of solution properties on the performance of ion separation via ME was systematically evaluated through numerical simulations. A finite element method (FEM) model was established, in which multiple physical fields were considered. To verify the model, ion analysis experiments were conducted under corresponding conditions. Based on the validated model, a series of simulations were carried out to evaluate the effects of solution properties on separation performance. It was demonstrated that solution properties significantly affect the separation behavior, including ion arrival time, concentration-peak height, and separation resolution. These findings suggest that solution properties should not be overlooked in the design and optimization of ME systems. The simulation approach presented in this work is expected to provide valuable insights into the improvement of ion analysis using ME. Full article

(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)

► Show Figures

Figure 1

13 pages, 1833 KB

Open AccessArticle

A Ratiometric Fluorescent Probe Based on CDs-Functionalized UiO-66 for Efficient Detection of Uric Acid

by Hongmei Gao, Yourong Zhao, Yuhong Xie, Yiying Wang, Jie Che, Daojiang Gao and Zhanglei Ning

Chemosensors 2025, 13(9), 340; https://doi.org/10.3390/chemosensors13090340 - 5 Sep 2025

Viewed by 207

Abstract

In this study, a novel carbon quantum dots-functionalized UiO-66 composite was successfully prepared via the post-synthetic modification method and further developed into a ratiometric fluorescent probe for detecting uric acid. The composite demonstrates excellent structural and luminescent stability under challenging environmental conditions. As [...] Read more.

In this study, a novel carbon quantum dots-functionalized UiO-66 composite was successfully prepared via the post-synthetic modification method and further developed into a ratiometric fluorescent probe for detecting uric acid. The composite demonstrates excellent structural and luminescent stability under challenging environmental conditions. As a ratiometric fluorescent probe, its recognition principle relies on the ratio of response signals from two different fluorescent emission centers in the composite. In the presence of uric acid, the fluorescence emission intensity at 430 nm from CDs did not change significantly. However, the fluorescence intensity at 545 nm from Tb³⁺ ions decreased remarkably. This material was evaluated for its capacity to sense urinary components and was shown to specifically recognize uric acid over a wide concentration range (0~5 × 10⁻³ M). Moreover, it exhibited strong resistance to interference and high sensitivity in uric acid detection. The detection limit (LOD) was determined to be 0.102 μM through quantitative analysis. The sensing mechanism was validated through spectral overlap and fluorescence lifetime analysis, which can be attributed to the fluorescence resonance energy transfer (FRET) process. This ratiometric fluorescent probe provides an efficient and reliable strategy for detecting the biomarker uric acid. Full article

(This article belongs to the Special Issue Advanced Colorimetric and Fluorescent Sensors and Their Application in Detection, 2nd Edition)

► Show Figures

Figure 1

20 pages, 7452 KB

Open AccessArticle

Efficient Cataluminescence Sensor for Detecting Methanol Based on NiCo₂O₄//MIL-Ti₁₂₅ Polyhedral Composite Nano-Materials

by Hongyan Wang, Ziyu Shao, Mao Cai, Guoji Shi and Bai Sun

Chemosensors 2025, 13(9), 339; https://doi.org/10.3390/chemosensors13090339 - 5 Sep 2025

Viewed by 174

Abstract

Since methanol has a significant health hazard due to its inherent toxicity, it is urgent to develop a method capable of rapid, sensitive, and continuous monitoring of methanol. The present study successfully synthesized a NiCo₂O₄/MIL-Ti₁₂₅ composite material and [...] Read more.

Since methanol has a significant health hazard due to its inherent toxicity, it is urgent to develop a method capable of rapid, sensitive, and continuous monitoring of methanol. The present study successfully synthesized a NiCo₂O₄/MIL-Ti₁₂₅ composite material and conducted a comprehensive analysis of its effectiveness for the detection of methanol employing cataluminescence (CTL) technology. The findings demonstrated that the composite material displays marked CTL in response to methanol, showcasing notable sensitivity, selectivity, and stability. The composite’s heterogeneous structure significantly improves the adsorption and reaction efficiency of methanol and further reduces the sensor’s working temperature. Under the optimal conditions of 215 °C and a flow rate of 300 mL/min, the CTL signal intensity is governed by the equation Y = 10.388X − 4.473 (R² = 0.982), with a detection limit as low as 0.431 ppm. The NiCo₂O₄/MIL-Ti₁₂₅ sensor exhibits high selectivity towards methanol. In addition, a relative standard deviation (RSD) of 4.95% demonstrates its excellent stability. Utilizing X-ray photoelectron spectroscopy (XPS), the study investigated the impact of elemental valence changes on the CTL process. We believe that the NiCo₂O₄/MIL-Ti₁₂₅ composite material, as a high-performance low-temperature CTL methanol sensor, is promising for applications. Full article

(This article belongs to the Special Issue Functional Nanomaterial-Based Gas Sensors and Humidity Sensors)

► Show Figures

Figure 1

13 pages, 3462 KB

Open AccessArticle

Microcontact-Printed Optical Biosensor for Non-Invasive Detection of TNF-α: Point-of-Care Monitoring of Heart Failure

by Abdoullatif Baraket, Alexi Bonament, Abdellatif Aarfane, Hamid Nasrellah, Meryem Bensemlali, Joan Bausells, Nicole Jaffrezic-Renault, Nadia Zine and Abdelhamid Errachid

Chemosensors 2025, 13(9), 338; https://doi.org/10.3390/chemosensors13090338 - 5 Sep 2025

Viewed by 293

Abstract

Tumor Necrosis Factor-alpha (TNF-α) is a pro-inflammatory cytokine strongly associated with the early onset and progression of heart failure (HF). In this study, we present the design and fabrication of a label-free, fluorescence-based biosensor for the detection of TNF-α cytokines. The biosensor is [...] Read more.

Tumor Necrosis Factor-alpha (TNF-α) is a pro-inflammatory cytokine strongly associated with the early onset and progression of heart failure (HF). In this study, we present the design and fabrication of a label-free, fluorescence-based biosensor for the detection of TNF-α cytokines. The biosensor is constructed using microcontact printing (μCP) to pattern Triethoxysilylundecanal (TESUD) on oxygen plasma-activated polydimethylsiloxane (PDMS) substrates, forming self-assembled monolayers (SAMs) of microstructures. TNF-α antibodies are then covalently immobilized via imine coupling. Detection of TNF-α cytokines at 50 µg/mL was achieved via an optical “sandwich” immunoassay with rhodamine-labeled secondary antibodies, enabling visualization by fluorescence microscopy. Surface wettability analysis confirmed successful stepwise functionalization, while imaging revealed well-defined microstructures and specific immune binding of TNF-α. This platform demonstrates a proof-of-concept and offers a non-invasive, sensitive, and cost-effective alternative for the early detection of TNF-α in biological fluids, with potential applications in HF monitoring. Full article

(This article belongs to the Special Issue Advanced Biosensors for Point-of-Care Testing in Analytical Chemistry)

► Show Figures

Figure 1

34 pages, 1914 KB

Open AccessReview

From Volatile Profiling to Sensory Prediction: Recent Advances in Wine Aroma Modeling Using Chemometrics and Sensor Technologies

by Fernanda Cosme, Alice Vilela, Ivo Oliveira, Alfredo Aires, Teresa Pinto and Berta Gonçalves

Chemosensors 2025, 13(9), 337; https://doi.org/10.3390/chemosensors13090337 - 5 Sep 2025

Viewed by 1736

Abstract

Wine quality is closely linked to sensory attributes such as aroma, taste, and mouthfeel, all of which are influenced by grape variety, “terroir”, and vinification practices. Among these, aroma is particularly important for consumer preference, and it results from a complex interplay of [...] Read more.

Wine quality is closely linked to sensory attributes such as aroma, taste, and mouthfeel, all of which are influenced by grape variety, “terroir”, and vinification practices. Among these, aroma is particularly important for consumer preference, and it results from a complex interplay of numerous volatile compounds. Conventional sensory methods, such as descriptive analysis (DA) performed by trained panels, offer valuable insights but are often time-consuming, resource-intensive, and subject to individual variability. Recent advances in sensor technologies—including electronic nose (E-nose) and electronic tongue (E-tongue)—combined with chemometric techniques and machine learning algorithms, offer more efficient, objective, and predictive approaches to wine aroma profiling. These tools integrate analytical and sensory data to predict aromatic characteristics and quality traits across diverse wine styles. Complementary techniques, including gas chromatography (GC), near-infrared (NIR) spectroscopy, and quantitative structure–odor relationship (QSOR) modeling, when integrated with multivariate statistical methods such as partial least squares regression (PLSR) and neural networks, have shown high predictive accuracy in assessing wine aroma and quality. Such approaches facilitate real-time monitoring, strengthen quality control, and support informed decision-making in enology. However, aligning instrumental outputs with human sensory perception remains a challenge, highlighting the need for further refinement of hybrid models. This review highlights the emerging role of predictive modeling and sensor-based technologies in advancing wine aroma evaluation and quality management. Full article

(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges (Fourth Edition))

► Show Figures

Figure 1

17 pages, 4556 KB

Open AccessArticle

Multi-Element Prediction of Soil Nutrients Using Laser-Induced Breakdown Spectroscopy and Interpretable Multi-Output Weight Network

by Xiaolong Li, Liuye Cao, Chengxu Lyu, Zhengyu Tao, Anan Tao, Wenwen Kong and Fei Liu

Chemosensors 2025, 13(9), 336; https://doi.org/10.3390/chemosensors13090336 - 5 Sep 2025

Viewed by 291

Abstract

Rapid and green detection of soil nutrients is essential for soil fertility and plant growth. However, traditional methods cannot meet the needs of rapid detection, and the reagents easily cause environmental pollution. Hence, we proposed a multivariable output weighting-network (MW-Net) combined with laser-induced [...] Read more.

Rapid and green detection of soil nutrients is essential for soil fertility and plant growth. However, traditional methods cannot meet the needs of rapid detection, and the reagents easily cause environmental pollution. Hence, we proposed a multivariable output weighting-network (MW-Net) combined with laser-induced breakdown spectroscopy (LIBS) to achieve rapid and green detection for three soil nutrients. For a better spectral signal-to-background ratio (SBR), the two important parameters of delay time and gate width were optimized. Then, the spectral noise was removed by the near-zero standard deviation method. Three common quantitative models were investigated for single-element prediction, which are usually applied in LIBS analysis. Also, multi-element prediction was investigated using MW-Net. The results showed that MW-Net outperformed other models generally with very good quantification for soil total N and K (the determination coefficients in the prediction set (R_p²) of 0.75 and 0.83 and the relative percent difference in the prediction sets (RPD) of 2.05 and 2.43) and excellent indirect determination for soil exchangeable Ca (R_p² of 0.93 and RPD of 3.91). Finally, the interpretability was realized through feature extraction from MW-Net, indicating its design rationality. The preliminary results indicated that MW-Net combined with LIBS technology could quantify the three soil nutrients simultaneously, improving the detection efficiency, and it could possibly be deployed on a LIBS portable instrument in the future for precision agriculture. Full article

(This article belongs to the Special Issue Application of Laser-Induced Breakdown Spectroscopy, 2nd Edition)

► Show Figures

Figure 1

13 pages, 3271 KB

Open AccessArticle

One-Step Controlled Electrodeposition Fabrication of Ternary PtNiCo Nanosheets for Electrocatalytic Ammonia–Nitrogen Sensing

by Liang Zhang, Yue Han, Yingying Huang, Jiali Gu, Xinyue Wang and Chun Zhao

Chemosensors 2025, 13(9), 335; https://doi.org/10.3390/chemosensors13090335 - 4 Sep 2025

Viewed by 272

Abstract

The development of high-performance electrochemical sensors is crucial for ammonia–nitrogen detection. Therefore, in this study, we successfully prepared one ternary PtNiCo nanosheet via the one-step electrodeposition technique. The ratio of H₂PtCl₆·6H₂O, Ni(NO₃)₂·6H₂ [...] Read more.

The development of high-performance electrochemical sensors is crucial for ammonia–nitrogen detection. Therefore, in this study, we successfully prepared one ternary PtNiCo nanosheet via the one-step electrodeposition technique. The ratio of H₂PtCl₆·6H₂O, Ni(NO₃)₂·6H₂O and Co(NO₃)₂·6H₂O and electrodeposition time were controlled. Under optimal conditions, Pt₆Ni₂Co₂-2000 demonstrated outstanding electrocatalytic performance, exhibiting a high oxidation peak current of 45.27 mA and excellent long-term stability, retaining 88.09% of its activity after 12 h. Furthermore, the sensing performance of Pt₆Ni₂Co₂-2000 was evaluated, revealing high sensitivity (10.01 μA μM⁻¹), a low detection limit (0.688 µM), strong anti-interference capability, great reusability, great reproducibility, and remarkable long-term stability. Additionally, recovery tests conducted in tap water, lake water, and seawater yielded highly favorable results. This study demonstrated that designing Pt-based alloys can not only enhance the electrochemical performance of Pt but also serve as an effective strategy for improving electrocatalytic ammonia oxidation and ammonia–nitrogen detection. Full article

(This article belongs to the Section Nanostructures for Chemical Sensing)

► Show Figures

Figure 1

13 pages, 2627 KB

Open AccessArticle

Fluorescent Assay for Salmonella Detection Based on Triangle Multivalent Aptamer-Initiated Catalytic Hairpin Assembly

by Shu Chen, Zhen Wang, Wen Lu, Xingxing Peng, Chuanpi Wang, Zhaohui Qiao and Xiude Hua

Chemosensors 2025, 13(9), 334; https://doi.org/10.3390/chemosensors13090334 - 4 Sep 2025

Viewed by 277

Abstract

Salmonella poses a severe global threat to food safety and public health, necessitating rapid, sensitive, and reliable detection methods. Conventional techniques often suffer from complexity, time consumption, cost, or limited sensitivity. To address this, we developed a novel enzyme-free fluorescence detection platform, termed [...] Read more.

Salmonella poses a severe global threat to food safety and public health, necessitating rapid, sensitive, and reliable detection methods. Conventional techniques often suffer from complexity, time consumption, cost, or limited sensitivity. To address this, we developed a novel enzyme-free fluorescence detection platform, termed the MTAI-CHA system, integrating magnetic nanoparticle-based triangle multivalent aptamer-initiators (MTAI) with catalytic hairpin assembly (CHA) signal amplification. The triangular DNA nanostructure contained significantly enhanced binding affinity of multivalent aptamers, increasing the sensitivity compared to monovalent aptamers. The optimized MTAI-CHA system demonstrated exceptional performance: a low detection limit of 10 CFU/mL and excellent specificity against non-target pathogens. This sensitive, specific, and robust strategy, leveraging multivalent aptamer recognition and enzyme-free signal amplification, holds significant potential for rapid pathogen screening in food safety, clinical diagnostics, and environmental monitoring, with adaptability to other targets via aptamer substitution. Full article

(This article belongs to the Special Issue Advanced Material-Based Fluorescent Sensors)

► Show Figures

Figure 1

5 pages, 176 KB

Open AccessEditorial

Advanced Chemosensors for Gas Detection

by Shuai Chen

Chemosensors 2025, 13(9), 333; https://doi.org/10.3390/chemosensors13090333 - 4 Sep 2025

Viewed by 267

Abstract

The exploration of gas sensing technologies lies at the forefront of modern scientific and technological advancements [...] Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

13 pages, 888 KB

Open AccessReview

Use of Chemometrics for the Authentication, Characterization and Detection of Adulteration of Cypriot Products Registered Under EU Quality Schemes: A Review

by Maria Tarapoulouzi, Ioannis Pashalidis and Charis R. Theocharis

Chemosensors 2025, 13(9), 332; https://doi.org/10.3390/chemosensors13090332 - 3 Sep 2025

Viewed by 300

Abstract

This review explores the application of chemometric techniques for the authentication, characterization, and adulteration detection of Cypriot agri-food products registered under European Union quality schemes, including Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI). Given the increasing global demand for premium [...] Read more.

This review explores the application of chemometric techniques for the authentication, characterization, and adulteration detection of Cypriot agri-food products registered under European Union quality schemes, including Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI). Given the increasing global demand for premium and geographically linked food products, ensuring their authenticity and integrity has become critical. Although Halloumi cheese, wines, and Zivania are the most researched Cypriot products, additional studies are still needed. Chemometrics, when coupled with spectroscopy, offers robust analytical tools for distinguishing genuine products from their imitations by characterizing them. This review provides an overview of certified Cypriot products and focuses on published applications where chemometric approaches have been used to assess product origin, composition, and adulteration. The paper concludes with current challenges, methodological limitations, and future directions for expanding the role of chemometrics in food integrity verification within the context of EU geographical indications. Full article

(This article belongs to the Special Issue Chemometrics Tools Used in Chemical Detection and Analysis)

► Show Figures

Figure 1

12 pages, 1905 KB

Open AccessArticle

Enzymatic Transformation of Secondary Metabolites in Abeliophyllum distichum Extract by Viscozyme^® L Treatment

by Chang-Dae Lee, Eun-A Kim, Ho Sik Rho and Sanghyun Lee

Chemosensors 2025, 13(9), 331; https://doi.org/10.3390/chemosensors13090331 - 3 Sep 2025

Viewed by 284

Abstract

Abeliophyllum distichum is rich in polyphenols and flavonoids with various bioactivities; however, studies on enzymatic modifications to enhance its functional properties remain limited. This study investigated the effect of Viscozyme^® L treatment on the secondary metabolite profile of A. distichum leaves. Phytochemical [...] Read more.

Abeliophyllum distichum is rich in polyphenols and flavonoids with various bioactivities; however, studies on enzymatic modifications to enhance its functional properties remain limited. This study investigated the effect of Viscozyme^® L treatment on the secondary metabolite profile of A. distichum leaves. Phytochemical profiling using liquid chromatography–electrospray ionization tandem mass spectrometry revealed a decrease in the total number of detectable compounds, from 26 in the untreated extract to 16 in the enzyme-treated extract. Following Viscozyme^® L treatment, a notable shift in metabolite composition was observed, with significant enrichment of flavonoid glycosides, pyranone derivatives, and amino acid-related metabolites. Quantitative high-performance liquid chromatography analysis showed significant reductions in glycosylated compounds such as rutin (1), acteoside (2), and isoacteoside (3), while the aglycone quercetin (4) content increased more than four-fold compared to the control. These results indicate that Viscozyme^® L facilitates the deglycosylation of flavonoid glycosides into their aglycone forms. This enzymatic transformation suggests a potential strategy to enhance the bioavailability and functional value of A. distichum leaf extracts for nutraceutical and pharmaceutical applications. Full article

(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)

► Show Figures

Figure 1

12 pages, 2794 KB

Open AccessArticle

A Carbon Black-Based Non-Enzymatic Electrochemical Sensor for the Detection of Sunset Yellow in Beverages

by Zihui Li, Wenxue Chen, Qiongya Wan, Haoliang Li, Xuefeng Wang, Pengcheng Xu, Yuan Zhang, Yongheng Zhu and Xinxin Li

Chemosensors 2025, 13(9), 330; https://doi.org/10.3390/chemosensors13090330 - 2 Sep 2025

Viewed by 367

Abstract

This study presents a highly sensitive non-enzymatic electrochemical sensor for detecting Sunset Yellow, a common food additive in beverages, based on palladium-cerium oxide composite decorated carbon black (CB). The sensing material was prepared by depositing palladium nanoparticles onto cerium oxide nanocubes, followed by [...] Read more.

This study presents a highly sensitive non-enzymatic electrochemical sensor for detecting Sunset Yellow, a common food additive in beverages, based on palladium-cerium oxide composite decorated carbon black (CB). The sensing material was prepared by depositing palladium nanoparticles onto cerium oxide nanocubes, followed by the uniform dispersion of CB through sonication in a water bath. The strong metal–support interaction between palladium and cerium oxide significantly enhances catalytic activity, while the CB ensures excellent conductivity and structural support for the catalyst. Under optimized conditions, the sensor exhibits a linear response to Sunset Yellow concentrations in the range from 1 to 100 nM, with a limit of detection (LOD) of 0.056 nM. Additionally, the sensor demonstrates remarkable selectivity and stability. Practical application in real orange juice samples yielded recoveries from 99.11% and 101.34%, confirming its reliability for real-world beverage analysis. Full article

(This article belongs to the Section Electrochemical Devices and Sensors)

► Show Figures

Figure 1

20 pages, 3004 KB

Open AccessArticle

Synthesis, Characterization, and Evaluation of Photocatalytic and Gas Sensing Properties of ZnSb₂O₆ Pellets

by Jacob Morales-Bautista, Héctor Guillén-Bonilla, Lucia Ivonne Juárez-Amador, Alex Guillén-Bonilla, Verónica-María Rodríguez-Betancourtt, Jorge Alberto Ramírez-Ortega, José Trinidad Guillén-Bonilla and María de la Luz Olvera-Amador

Chemosensors 2025, 13(9), 329; https://doi.org/10.3390/chemosensors13090329 - 2 Sep 2025

Cited by 1 | Viewed by 410

Abstract

This work reports a low-cost, microwave-assisted wet chemistry synthesis of zinc antimonate (ZnSb₂O₆) powders with a trirutile structure, yielding highly homogeneous, nanometric particles. X-ray diffraction (XRD) confirmed the formation of the trirutile phase with lattice parameters of a = [...] Read more.

This work reports a low-cost, microwave-assisted wet chemistry synthesis of zinc antimonate (ZnSb₂O₆) powders with a trirutile structure, yielding highly homogeneous, nanometric particles. X-ray diffraction (XRD) confirmed the formation of the trirutile phase with lattice parameters of a = 4.664 Å and c = 9.263 Å, and an estimated crystallite size of 42 nm. UV–vis spectroscopy revealed a bandgap of 3.35 eV. Scanning electron microscopy (SEM) showed that ethylenediamine, as a chelating agent, formed porous microstructures of microrods and cuboids, ideal for enhanced gas adsorption. Brunauer–Emmett–Teller (BET) analysis revealed a specific surface area of 6 m²/g and a total pore volume of 0.0831 cm³/g, indicating a predominantly mesoporous structure. The gas sensing properties of ZnSb₂O₆ pellets were evaluated in CO and C₃H₈ atmospheres at 100, 200, and 300 °C. The material exhibited high sensitivity at 300 °C, where the maximum responses were 5.86 for CO at 300 ppm and 1.04 for C₃H₈ at 500 ppm. The enhanced sensitivity at elevated temperatures was corroborated by a corresponding decrease in electrical resistivity. Furthermore, the material demonstrated effective photocatalytic activity, achieving up to 60% degradation of methylene blue and 50% of malachite green after 300 min of UV irradiation, with the process following first-order reaction kinetics. These results highlight that ZnSb₂O₆ synthesized by this method is a promising bifunctional material for gas sensing and photocatalytic applications. Full article

(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)

► Show Figures

Figure 1

27 pages, 4109 KB

Open AccessReview

What’s New with the Old Ones: Updates on Analytical Methods for Fossil Research

by Luminița Ghervase and Monica Dinu

Chemosensors 2025, 13(9), 328; https://doi.org/10.3390/chemosensors13090328 - 2 Sep 2025

Viewed by 1143

Abstract

Fossils are portals to the past, providing researchers with vital information about the evolution of life on Earth throughout the geological eras. The present study synthesizes the recent trends in fossil research, emphasizing the most common techniques found in the specialized literature over [...] Read more.

Fossils are portals to the past, providing researchers with vital information about the evolution of life on Earth throughout the geological eras. The present study synthesizes the recent trends in fossil research, emphasizing the most common techniques found in the specialized literature over the past 20 years. The bibliographic survey revealed that destructive methods continue to play a significant role in scientific production related to this topic, particularly in studies on 3D morphologies, diagenesis, nutritional ecology, dating, elucidating dietary or habitat preferences, or understanding the physiology of extinct species. However, noninvasive tools, such as Raman spectroscopy, are rapidly rising, particularly when integrated with imaging techniques. As such, fossil research continues to advance even beyond the borders of our planet, exploring extraterrestrial samples in a quest to unlock the universal mystery of life. At the same time, the advent of advanced AI methods—particularly model chatbots that rival the capabilities of experienced scientists—has facilitated and enhanced data interpretation and classification. As fossil research evolves, upcoming technological advancements in spatial resolution, penetration depth, and detection sensitivity will integrate state-of-the-art spectroscopic tools. This will undoubtedly take fossil research to new heights, generating breakthroughs that optimize analysis while preserving invaluable specimens. Overall, the present study offers a holistic overview of analytical techniques through meta-analysis and bibliometric mapping, including a critical assessment of commonly used methods and offering a glimpse into the integration of machine learning and AI tools in fossil research. Full article

(This article belongs to the Special Issue Spectroscopic Techniques for Chemical Analysis)

► Show Figures

Figure 1

14 pages, 2649 KB

Open AccessArticle

The Classification of Synthetic- and Petroleum-Based Hydrocarbon Fluids Using Handheld Raman Spectroscopy

by Javier E. Hodges, Kailee Marchand, Geraldine Monjardez and Jorn Chi-Chung Yu

Chemosensors 2025, 13(9), 327; https://doi.org/10.3390/chemosensors13090327 - 2 Sep 2025

Viewed by 460

Abstract

Hydrocarbon fluids have a widespread presence in modern society due to their role in the global energy and fuel supply. The ability to distinguish between hydrocarbon fluids from different manufacturing processes is essential in industrial and government settings. Currently, performing such analyses is [...] Read more.

Hydrocarbon fluids have a widespread presence in modern society due to their role in the global energy and fuel supply. The ability to distinguish between hydrocarbon fluids from different manufacturing processes is essential in industrial and government settings. Currently, performing such analyses is expensive and time-consuming, as standard practice involves sending samples to a laboratory for gas chromatography-mass spectrometry (GC-MS) analysis. The inherent limitations of traditional separation techniques often make them unsuitable for the demands of real-time process monitoring and control. This work proposes the use of handheld Raman spectroscopy for rapid classification of petroleum- and synthetic-based hydrocarbon fluids. A total of 600 Raman spectra were collected from six different hydraulic fluids and analyzed. Preliminary visual observations revealed reproducible spectral differences between various types of hydraulic fluids. Principal component analysis (PCA) and linear discriminant analysis (LDA) were used to investigate the data further. The findings indicate that handheld Raman spectrometers are capable of detecting chemical features of hydrocarbon fluids, supporting the classification of their formulations. Full article

(This article belongs to the Special Issue Chemical Sensing and Analytical Methods for Forensic Applications)

► Show Figures

Figure 1

24 pages, 8771 KB

Open AccessArticle

Thiamethoxam Sensing Using Gelatin Carbon Dots: Influence of Synthesis and Purification Methods

by Mayara Martins Caetano and Renata Galvão de Lima

Chemosensors 2025, 13(9), 326; https://doi.org/10.3390/chemosensors13090326 - 1 Sep 2025

Viewed by 455

Abstract

This innovative study introduces an eco-conscious and cost-effective approach to synthesizing gelatin-based carbon dots (CDs) via two distinctive methods: hydrothermal processing in a muffle furnace (CDs-MF) and domestic microwave (CDs-MW). Both strategies harness natural, low-cost materials and prioritize simplicity, sustainability, and environmental friendliness, [...] Read more.

This innovative study introduces an eco-conscious and cost-effective approach to synthesizing gelatin-based carbon dots (CDs) via two distinctive methods: hydrothermal processing in a muffle furnace (CDs-MF) and domestic microwave (CDs-MW). Both strategies harness natural, low-cost materials and prioritize simplicity, sustainability, and environmental friendliness, culminating in effective fluorescent sensing of the pesticide thiamethoxam (TMX). For the hydrothermal route, the investigation explores two purification approaches—ultracentrifugation (CDs-MF-C) and 0.22 µm syringe filtration (CDs-MF-F)—while the microwave-derived CDs (CDs-MW) undergo dialysis alone. This study aims to investigate how synthesis and purification impact the CDs structural, morphological, and photophysical characteristics. The difference in size was obtained from transmission electron microscopy (TEM): 30–40 nm for CDs-MF-C, 12–15 nm for CDs-MF-F, and 3–6 nm for CDs-MW. Fluorescence emission performance reveals that CDs-MF-F performs a fluorescence quantum yield of 27%, CDs-MF-C at 23%, and CDs-MW at a modest 3%. All variants exhibit TMX detection via fluorescence quenching through the inner filter effect (IFE). Analytically, CDs-MF-C stands out with the lowest detection limit (LOD = 0.396 ppm) and quantification limit (LOQ = 1.317 ppm), followed by CDs-MF-F (LOD = 0.475 ppm; LOQ = 1.585 ppm) and CDs-MW (LOD = 0.549 ppm; LOQ = 1.831 ppm). These findings emphasize the unique interplay between the synthesis pathway, purification strategy, and functional performance, demonstrating the critical importance of tuning structural properties for optimizing carbon-dot sensors. Full article

(This article belongs to the Special Issue The Recent Progress and Applications of Optical Chemical Sensors)

► Show Figures

Graphical abstract

14 pages, 1756 KB

Open AccessArticle

In-Depth Investigation of the Chemical Profile of Pelargonium odoratissimum (L.) L’Hér. Hydrolate by SPME-GC/MS, GC/MS, LVI-GC/MS and PTR-Tof-MS Techniques

by Cosimo Taiti, Vittorio Vinciguerra, Monica Mollica Graziano, Elisa Masi and Stefania Garzoli

Chemosensors 2025, 13(9), 325; https://doi.org/10.3390/chemosensors13090325 - 1 Sep 2025

Viewed by 365

Abstract

Hydrolates are aromatic aqueous solutions saturated with volatile water-soluble compounds of essential oil. Despite their potential, hydrolates remain less explored than essential oils. In this work, the hydrolate of Pelargonium odoratissimum (L.) L’Hér. has been analyzed by multiple analytical techniques in order to [...] Read more.

Hydrolates are aromatic aqueous solutions saturated with volatile water-soluble compounds of essential oil. Despite their potential, hydrolates remain less explored than essential oils. In this work, the hydrolate of Pelargonium odoratissimum (L.) L’Hér. has been analyzed by multiple analytical techniques in order to describe its chemical composition. Headspace (HS-) and Direct Immersion-Solid Phase Microextraction-Gas Chromatography/Mass spectrometry (DI-SPME-GC/MS) and Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) were employed to reveal the VOC emission from the hydrolate. Further, a direct injection of the pure hydrolate and of the hydrolate after extraction with hexane was performed by Large-Volume Injection Gas Chromatography/Mass Spectrometry (LVI-GC/MS) and GC/MS. The results obtained by HS- and DI-SPME-GC/MS highlighted a nearly overlapping chemical profile with linalool, isomenthone, and α-terpineol as the main volatiles. On the other hand, analysis of the hydrolate by GC/MS after solvent extraction revealed a lower overall number of compounds but allowed the detection of thujone and cis-linalool oxide. In comparison, LVI-GC/MS was the technique that allowed the identification of a higher number of volatiles with citronellol, linalool, and α-terpineol as the principal compounds. Finally, PTR-ToF-MS was a fundamental approach to quantify and evaluate total terpene emissions from this complex matrix starting from low-molecular-weight compounds such as acetylene, methanol, acetaldehyde, acetone, and ethanol, which were the most abundant. Among the detected compounds, dimethyl sulfide and small amounts of dimethyl-furan and 2-butylfuran were also identified. Overall, the findings showed that the hydrolate was rich in monoterpene compounds while sesquiterpene compounds were missing. A very low intensity relating to sesquiterpenes was recorded only by PTR-ToF-MS technique. Full article

(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges (Fourth Edition))

► Show Figures

Figure 1

13 pages, 2106 KB

Open AccessArticle

Oxygen Vacancy-Engineered Cu₂O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection

by Di Zhang, Zhengfang Qu, Chenchen Li, Huan Wang, Yong Zhang, Xiang Ren and Rui Xu

Chemosensors 2025, 13(9), 324; https://doi.org/10.3390/chemosensors13090324 - 1 Sep 2025

Viewed by 422

Abstract

The sensitive detection of n-butanol is of high scientific and practical importance for ensuring safety in industrial production. In this study, hollow Cu₂O@CuS core–shell nanocubic heterostructures were fabricated via a multistep templating method. The Cu₂O@CuS heterostructures demonstrated exceptional performance, [...] Read more.

The sensitive detection of n-butanol is of high scientific and practical importance for ensuring safety in industrial production. In this study, hollow Cu₂O@CuS core–shell nanocubic heterostructures were fabricated via a multistep templating method. The Cu₂O@CuS heterostructures demonstrated exceptional performance, with an ultrahigh Brunauer–Emmett–Teller specific surface area that provided abundant active sites and a unique hollow architecture that enhanced mass transport and improved gas adsorption/desorption kinetics. High-density surface oxygen vacancies on the Cu₂O@CuS nanocubic heterostructures provide a key structural basis for the preferential adsorption of n-butanol molecules on its surface. The p–p heterojunction configuration further enhanced selective sensor response by optimizing the charge carrier separation and band structure modulation. The developed sensor achieved a detection limit of 3.18 ppm while exhibiting outstanding sensitivity, stability, and response time, meeting the stringent requirements for n-butanol detection in both industrial and agricultural settings. This work provides new insights on how to design materials for gas sensors. Full article

(This article belongs to the Special Issue Functionalized Material-Based Gas Sensing)

► Show Figures

Figure 1

12 pages, 3302 KB

Open AccessArticle

Multivariate Calibration for Selective Analysis of Hydrogen Sulfide and Carbon Monoxide with Thermal Modulation of the SnO₂–PdO Sensor

by Alexey Shaposhnik, Pavel Moskalev, Alexey Vasiliev, Kirill Oreshkin, Alexey Zviagin, Elena Vysotskaya, Sergey Turishchev and Iuliia Kakuliia

Chemosensors 2025, 13(9), 323; https://doi.org/10.3390/chemosensors13090323 - 1 Sep 2025

Viewed by 365

Abstract

In this study, multivariate data processing during thermal modulation of the SnO₂–PdO gas sensor was performed using the multivariate calibration (MC) method. We propose to supplement this method with a procedure that allows the solving of problems of both quantitative and [...] Read more.

In this study, multivariate data processing during thermal modulation of the SnO₂–PdO gas sensor was performed using the multivariate calibration (MC) method. We propose to supplement this method with a procedure that allows the solving of problems of both quantitative and qualitative analysis. The advantage of the extended method (Multivariate Calibration for Selective Analysis, MCSA) compared to other methods is its modest requirements for computing resources, which allows it to be easily implemented on standard microcontrollers. The MCSA method opens up the prospect of creating compact gas analyzers of a new generation, capable of selective gas analysis in hard-to-reach places in an autonomous mode. The implementation of the MCSA method was demonstrated using the example of selective determination of hydrogen sulfide and carbon monoxide by a sensor whose temperature periodically changed from 100 to 450 °C. The training sample data were transformed by the MCSA method, which allowed for successful qualitative and quantitative analysis of the test sample data. Full article

(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Chemosensors, Volume 13, Issue 9 (September 2025) – 36 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI