Chemosensors

16 pages, 1856 KB

Open AccessArticle

Rapid Smartphone Colorimetric Determination of Starch and Ultraviolet Spectrophotometry Quantification of Lignin in Chinese Chrysanthemum Teas

by Wenchen Li and Weiying Lu

Chemosensors 2025, 13(12), 434; https://doi.org/10.3390/chemosensors13120434 - 16 Dec 2025

Viewed by 259

Abstract

Chrysanthemum, a traditional medicinal and edible plant, possesses diverse health-promoting properties attributed to its rich profile of bioactive compounds. However, the intrinsic quality, influenced by the composition of fundamental components like starch and lignin, varies significantly across different cultivars and origins. This study [...] Read more.

Chrysanthemum, a traditional medicinal and edible plant, possesses diverse health-promoting properties attributed to its rich profile of bioactive compounds. However, the intrinsic quality, influenced by the composition of fundamental components like starch and lignin, varies significantly across different cultivars and origins. This study establishes a comprehensive phytochemical profile of 12 representative Chinese chrysanthemum cultivars by systematically quantifying their starch and lignin contents. Furthermore, it develops and validates a novel, low-cost rapid detection method for starch utilizing smartphone-based colorimetry. The starch content, determined by a colorimetric anthrone-sulfuric acid assay, ranged from 2.68 to 18.69 g/100 g, while the lignin content, measured via the acetyl bromide digestion followed by UV spectrophotometry at 280 nm, varied from 4.21 to 13.63 g/100 g, revealing substantial inter-cultivar differences. For starch analysis, a low-cost, immediate, general-purpose, and high-throughput (LIGHt) smartphone-based colorimetry was implemented. Standard curves constructed from both absorbance and the LIGHt assay demonstrated excellent linearity (R² > 0.99). The method’s performance was evaluated under different lighting conditions and across various smartphone models. The UV spectrophotometry condenses lignin quantification to a single 30-min digestion–reading cycle, bypassing the two-day Klason protocol and increases efficiency greatly. The work successfully provides a foundational component analysis and validates a portable, high-throughput framework for on-site quality control of plant-based products, demonstrating the strong potential of smartphone-based colorimetry for rapid starch detection and a complementary laboratory-scale lignin assay. Full article

(This article belongs to the Special Issue Low-Cost Chemosensors for Applications in Environment, Health, Food, and Industry Process Control, 2nd Edition)

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16 pages, 6098 KB

Open AccessArticle

Eco-Friendly Synthesis and Paper Immobilization of AgNPs for Portable Colorimetric Detection of Hg²⁺ in Water

by Nevena Radivojević, Sanja Knežević, Stefan Graovac, Vladimir Rajić, Tamara Terzić, Nebojša Potkonjak, Tamara Lazarević-Pašti and Vedran Milanković

Chemosensors 2025, 13(12), 433; https://doi.org/10.3390/chemosensors13120433 - 16 Dec 2025

Viewed by 363

Abstract

Mercury’s severe toxicity and persistence demand fast, low-cost, and sustainable detection. In this work, a Juglans regia ethanolic extract is introduced as an efficient biogenic reducing and stabilizing agent for the green synthesis of silver nanoparticles (AgNPs). This plant-mediated route enables environmentally friendly [...] Read more.

Mercury’s severe toxicity and persistence demand fast, low-cost, and sustainable detection. In this work, a Juglans regia ethanolic extract is introduced as an efficient biogenic reducing and stabilizing agent for the green synthesis of silver nanoparticles (AgNPs). This plant-mediated route enables environmentally friendly nanoparticle formation with suitable optical properties for sensing applications. To overcome the poor visual selectivity observed in the colloidal AgNPs suspension, the nanoparticles were immobilized onto filter paper to produce a solid-phase colorimetric sensor. The paper-based platform exhibited a highly selective response toward Hg²⁺, showing complete suppression of the yellow coloration exclusively in the presence of Hg²⁺, even when challenged with a 200-fold excess of potentially interfering ions. Quantitative colorimetric analysis revealed a broad linear detection range from 1 × 10⁻⁸ to 1 × 10⁻³ mol dm⁻³ and an excellent limit of detection of 1.065 × 10⁻⁸ mol dm⁻³, with visible color changes consistent with the calculated values. The sensor’s performance was further validated using real tap water samples, with recovery values ranging from 96% to 102%, confirming minimal matrix interference and reliable quantification. Altogether, this study demonstrates that Juglans regia-mediated AgNPs, integrated into a simple paper-based format, provide a fully green, low-cost, and portable platform for sensitive and selective on-site detection of Hg²⁺ in environmental waters. Full article

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

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24 pages, 3680 KB

Open AccessReview

Laser-Induced Graphene Electrochemical Sensors: An Emerging Platform for Agri-Food and Environmental Detection

by Xinyang Cui, Tingting Gu, Kexin Ma, Jiwu Zeng and Hongqi Xia

Chemosensors 2025, 13(12), 432; https://doi.org/10.3390/chemosensors13120432 - 15 Dec 2025

Viewed by 465

Abstract

Harmful substances in food and agricultural environments pose significant risks to human health, necessitating the development of sensitive detection technologies. Electrochemical sensors are ideal for rapid monitoring because of their low cost, high efficiency, and portability. Recently developed laser-induced graphene (LIG)-based electrochemical sensors [...] Read more.

Harmful substances in food and agricultural environments pose significant risks to human health, necessitating the development of sensitive detection technologies. Electrochemical sensors are ideal for rapid monitoring because of their low cost, high efficiency, and portability. Recently developed laser-induced graphene (LIG)-based electrochemical sensors have demonstrated exceptional potential owing to the unique structural properties and outstanding electrochemical performance of LIG. In this review, the key factors influencing the LIG material characteristics during fabrication are discussed. Then, LIG-based electrochemical sensors are systematically categorized as pristine LIG and nanomaterial-functionalized, biomaterial-modified, and polymer-functionalized electrochemical sensors, and their application in the detection of functional components, additives, and agrochemicals in food products, and the detection of environmental pollutants, is comprehensively analyzed. Finally, the current challenges and the directions for future development are discussed. Full article

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

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12 pages, 1311 KB

Open AccessArticle

Detection of Mercury Ions Using Graphene Nanoribbon-DNA Sensors Fabricated via Template Methods

by Jiaojiao Da, Haixia Shi, Vesna Antic, Milica Balaban, Bing Xie and Li Gao

Chemosensors 2025, 13(12), 431; https://doi.org/10.3390/chemosensors13120431 - 12 Dec 2025

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Abstract

To enhance the sensitivity of graphene-DNA sensors for Hg²⁺ detection, a novel graphene nanoribbon-DNA sensor was fabricated using a template-assisted approach. Silicon nanowires served as templates to decorate the graphene device, followed by plasma etching to delineate graphene nanoribbons. After template removal, [...] Read more.

To enhance the sensitivity of graphene-DNA sensors for Hg²⁺ detection, a novel graphene nanoribbon-DNA sensor was fabricated using a template-assisted approach. Silicon nanowires served as templates to decorate the graphene device, followed by plasma etching to delineate graphene nanoribbons. After template removal, the resulting sensors based on silicon nanowire templates were successfully constructed. DNA sequences containing four guanine bases were conjugated with graphene sensors prepared using the templates. The carboxyl groups on the edges of the graphene nanoribbons were activated with EDC/NHS chemistry to facilitate covalent bonding with amino-modified DNA. The kinetic response and Hg²⁺ detection capability of the fabricated sensors were characterized using a semiconductor parameter analyzer. Results indicated that the silicon nanowire-templated graphene nanoribbon sensor exhibited high sensitivity, with a detection limit of 3.62 pM. This innovative approach further improved the sensitivity of graphene-DNA sensors for Hg²⁺ detection. Full article

(This article belongs to the Special Issue Green Electrochemical Sensors for Trace Heavy Metal Detection)

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14 pages, 3752 KB

Open AccessArticle

A Facile Solid-Phase Synthesis of Scandium-Modified Carbon Dots for Fluorescent Sensing of Cu²⁺

by Yalei Dong, Wei Song, Jing Hu and Cuiling Ren

Chemosensors 2025, 13(12), 430; https://doi.org/10.3390/chemosensors13120430 - 11 Dec 2025

Viewed by 436

Abstract

Scandium-modified carbon dots (Sc-oCDs) were synthesized in this work through a solid-phase approach. The prepared Sc-oCDs exhibited excitation-independent emission properties, as well as photostability against pH, ionic strength, and UV irradiation. Their fluorescence quantum yields significantly exceeded those of unmodified counterparts, confirming effective [...] Read more.

Scandium-modified carbon dots (Sc-oCDs) were synthesized in this work through a solid-phase approach. The prepared Sc-oCDs exhibited excitation-independent emission properties, as well as photostability against pH, ionic strength, and UV irradiation. Their fluorescence quantum yields significantly exceeded those of unmodified counterparts, confirming effective Sc modification. The Sc-oCDs also possessed upconversion fluorescence at 542 nm with 980 nm excitation. Additionally, the as-prepared Sc-oCDs functioned as an effective fluorescent sensor for Cu²⁺, demonstrating selective fluorescence quenching. A linear correlation was observed between the quenching efficiency and Cu²⁺ concentration from 1 to 600 μM, achieving a detection limit of 0.167 μM. Operating via dynamic quenching, this sensing system achieved highly selective and rapid (<1 min) detection of Cu²⁺, enabling sensitive Cu²⁺ monitoring in aqueous samples. Full article

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

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27 pages, 3101 KB

Open AccessReview

Recent Progress in Nanomaterials for Electrochemical Sensing of Natural Bioactive Compounds

by Branka B. Petković, Miloš Ognjanović and Dalibor M. Stanković

Chemosensors 2025, 13(12), 429; https://doi.org/10.3390/chemosensors13120429 - 11 Dec 2025

Viewed by 495

Abstract

The market for bioactive compounds of natural origin has expanded greatly over the past few years. These compounds can be found as individual supplements or food additives. Due to the importance of this market, incorrect data on their composition can often be found. [...] Read more.

The market for bioactive compounds of natural origin has expanded greatly over the past few years. These compounds can be found as individual supplements or food additives. Due to the importance of this market, incorrect data on their composition can often be found. Therefore, monitoring their concentration is of great importance. Although there are various methods for their selective and sensitive determination, electrochemical sensors represent an important tool in this field. With the development of nanotechnology, additional importance has been given to these sensors. Strictly controlled synthesis procedures can yield nanomaterials with unique morphological properties and significantly improved electrocatalytic capabilities. The integration of two or more nanomaterials in the form of a nanocomposite and/or nanohybrids allows for the synergistic effect of each of the components. Thus, excellent final characteristics are obtained in the field of electrochemical sensors, such as improved sensor stability, selectivity, and lower detection limits. In recent years, various forms of carbon nanomaterials, polymer films, metal and metal oxide nanoparticles (or simply metal/metal oxide nanoparticles), MOFs, porous nanomaterials, MXenes, and others with clearly defined characteristics represent an important step forward in this field. Carefully prepared, these materials achieve strong interactions with selected analytes, which results in significant progress in analytical methods for monitoring biologically active compounds. Therefore, this review summarizes the latest trends in this field, focusing on the method of material preparation, final morphology and electrocatalytic properties, selectivity, and sensitivity. Conclusions and expected future directions in this field are also given in order to improve current analytical performance. Full article

(This article belongs to the Special Issue Nanostructured Materials for Electrochemical Sensing)

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10 pages, 1516 KB

Open AccessArticle

Polymer Electrolyte-Gated Organic Electrochemical Transistors for Bioinspired Neuromorphic Computing

by Banghua Wu, Lin Gao, Yujie Peng, Changjian Liu, Canghao Xu, Haihong Guo, Yong Huang and Junsheng Yu

Chemosensors 2025, 13(12), 428; https://doi.org/10.3390/chemosensors13120428 - 9 Dec 2025

Viewed by 563

Abstract

Organic electrochemical transistors (OECTs) are compelling artificial synapses because mixed ionic–electronic coupling and transport enables low-voltage, analog weight updates that mirror biological plasticity. Here, we engineered solid-state, polymer electrolyte-gated vertical OECTs (vOECTs) and elucidate how electrolyte molecular weight influences synaptic dynamics. Using Pg2T-T [...] Read more.

Organic electrochemical transistors (OECTs) are compelling artificial synapses because mixed ionic–electronic coupling and transport enables low-voltage, analog weight updates that mirror biological plasticity. Here, we engineered solid-state, polymer electrolyte-gated vertical OECTs (vOECTs) and elucidate how electrolyte molecular weight influences synaptic dynamics. Using Pg2T-T as the redox-active channel and pDADMAC polymer electrolytes spanning low- (~100 k), medium- (~300 k), and high- (~500 k) molecular weights, cyclic voltammetry reveals reversible Pg2T-T redox, while peak separation and current density systematically track ion transport kinetics. Increasing electrolyte molecular weight enlarges the transfer curve hysteresis (memory window ΔV_mem from ~0.15 V to ~0.50 V) but suppresses on-current, consistent with slower, more confining ion motion and stabilized partially doped states. Devices exhibit rich short- and long-term plasticity: paired-pulse facilitation (A₂/A₁ ≈ 1.75 at Δt = 50 ms), frequency-dependent EPSCs (low-pass accumulation), cumulative potentiation, and reversible LTP/LTD. A device-aware CrossSim framework built from continuous write/erase cycles (probabilistic LUT) supports Fashion-MNIST inference with high accuracy and bounded update errors (mean −0.02; asymmetry 0.198), validating that measured nonidealities remain algorithm-compatible. These results provide a materials-level handle on polymer–ion coupling to deterministically tailor temporal learning in compact, robust neuromorphic hardware. Full article

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

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18 pages, 5512 KB

Open AccessArticle

Development and Application of Online Rapid Monitoring Devices for Volatile Organic Compounds in Soil–Water–Air Systems

by Xiujuan Feng, Haotong Guo, Jing Yang, Chengliang Dong, Fuzhong Zhao and Shaozhong Cheng

Chemosensors 2025, 13(12), 427; https://doi.org/10.3390/chemosensors13120427 - 9 Dec 2025

Viewed by 342

Abstract

To overcome the limitations of lengthy laboratory testing cycles and insufficient on-site responsiveness, this study developed an online rapid monitoring device for volatile organic compounds (VOCs) in soil–water–air systems based on photoionization detection (PID) technology. The device integrates modular sensor units, incorporates an [...] Read more.

To overcome the limitations of lengthy laboratory testing cycles and insufficient on-site responsiveness, this study developed an online rapid monitoring device for volatile organic compounds (VOCs) in soil–water–air systems based on photoionization detection (PID) technology. The device integrates modular sensor units, incorporates an electromagnetic valve-controlled multi-medium adaptive switching system, and employs an internal heating module to enhance the volatilization efficiency of VOCs in water and soil samples. An integrated system was developed featuring “front-end intelligent data acquisition–network collaborative transmission–cloud-based warning and analysis”. The effects of different temperatures on the monitoring performance were investigated to verify the reliability of the designed system. A polynomial fitting model between concentration and voltage was established, showing a strong correlation (R² > 0.97), demonstrating its applicability for VOC detection in environmental samples. Field application results indicate that the equipment has operated stably for nearly three years in a mining area of Shandong Province and an industrial park in Anhui Province, accumulating over 600,000 valid data points. These results demonstrate excellent measurement consistency, long-term operational stability, and reliable data acquisition under complex outdoor conditions. The research provides a distributed, low-power, real-time monitoring solution for VOC pollution control in mining and industrial environments. It also offers significant demonstration value for standardizing on-site emergency monitoring technologies in multi-media environments and promoting the development of green mining practices. Full article

(This article belongs to the Special Issue Recent Progress on Sensors and Smart Systems for In-Situ Gas Monitoring)

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52 pages, 1966 KB

Open AccessReview

Emerging Novel Psychoactive Substances (2020–2025): GC-MS Approaches for Separation, Detection, and Characterization

by Dušan Dimić

Chemosensors 2025, 13(12), 426; https://doi.org/10.3390/chemosensors13120426 - 9 Dec 2025

Viewed by 1938

Abstract

The rapid emergence of novel psychoactive substances (NPSs) after 2020 has created one of the most dynamic analytical challenges in modern forensic science. Hundreds of new synthetic cannabinoids, synthetic cathinones, synthetic opioids, hallucinogens, and dissociatives, appearing as hybrid or structurally modified analogues of [...] Read more.

The rapid emergence of novel psychoactive substances (NPSs) after 2020 has created one of the most dynamic analytical challenges in modern forensic science. Hundreds of new synthetic cannabinoids, synthetic cathinones, synthetic opioids, hallucinogens, and dissociatives, appearing as hybrid or structurally modified analogues of conventional drugs, have entered the illicit market, frequently found in complex polydrug mixtures. This review summarizes recent advances in gas chromatography-mass spectrometry (GC-MS) for their detection, structural elucidation, and differentiation between 2020 and 2025 based on the ScienceDirect and Google Scholar databases. Due to its reproducible electron-ionization spectra, established reference libraries, and robustness toward complex matrices, GC-MS remains the primary tool for the separation and identification of emerging NPS. The current literature highlights significant improvements in extraction and pre-concentration procedures, derivatization strategies for thermally unstable analogues, and chromatographic optimization that enable discrimination between positional and stereoisomers. This review covers a wide range of matrices, including powders, herbal materials, vaping liquids, and infused papers, as well as biological specimens such as blood, urine, and hair. Chemometric interpretation of GC-MS data now supports automated classification and prediction of fragmentation pathways, while coupling with complementary spectroscopic techniques strengthens compound confirmation. The review emphasizes how continuous innovation in GC-MS methodology has paralleled the rapid evolution of the NPS landscape, ensuring its enduring role as a reliable, adaptable, and cost-effective platform for monitoring emerging psychoactive substances in seized materials. Full article

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

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21 pages, 3252 KB

Open AccessArticle

A Machine Learning-Based Calibration Framework for Low-Cost PM_2.5 Sensors Integrating Meteorological Predictors

by Xuying Ma, Yuanyuan Fan, Yifan Wang, Xiaoqi Wang, Zelei Tan, Danyang Li, Jun Gao, Leshu Zhang, Yixin Xu, Xueyao Liu, Shuyan Cai, Yuxin Ma and Yongzhe Huang

Chemosensors 2025, 13(12), 425; https://doi.org/10.3390/chemosensors13120425 - 8 Dec 2025

Viewed by 596

Abstract

Low-cost sensors (LCSs) have rapidly expanded in urban air quality monitoring but still suffer from limited data accuracy and vulnerability to environmental interference compared with regulatory monitoring stations. To improve their reliability, we proposed a machine learning (ML)-based framework for LCS correction that [...] Read more.

Low-cost sensors (LCSs) have rapidly expanded in urban air quality monitoring but still suffer from limited data accuracy and vulnerability to environmental interference compared with regulatory monitoring stations. To improve their reliability, we proposed a machine learning (ML)-based framework for LCS correction that integrates various meteorological factors at observation sites. Taking Tongshan District of Xuzhou City as an example, this study carried out continuous co-location data collection of hourly PM_2.5 measurements by placing our LCS (American Temtop M10+ series) close to a regular fixed monitoring station. A mathematical model was developed to regress the PM_2.5 deviations (PM_2.5 concentrations at the fixed station—PM_2.5 concentrations at the LCS) and the most important predictor variables. The data calibration was carried out based on six kinds of ML algorithms: random forest (RF), support vector regression (SVR), long short-term memory network (LSTM), decision tree regression (DTR), Gated Recurrent Unit (GRU), and Bidirectional LSTM (BiLSTM), and the final model was selected from them with the optimal performance. The performance of calibration was then evaluated by a testing dataset generated in a bootstrap fashion with ten time repetitions. The results show that RF achieved the best overall accuracy, with R² of 0.99 (training), 0.94 (validation), and 0.94 (testing), followed by DTR, BiLSTM, and GRU, which also showed strong predictive capabilities. In contrast, LSTM and SVR produced lower accuracy with larger errors under the limited data conditions. The results demonstrate that tree-based and advanced deep learning models can effectively capture the complex nonlinear relationships influencing LCS performance. The proposed framework exhibits high scalability and transferability, allowing its application to different LCS types and regions. This study advances the development of innovative techniques that enhance air quality assessment and support environmental research. Full article

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13 pages, 1864 KB

Open AccessArticle

Impact of Ultrasonic-Assisted, Glutathione-Enriched Inactive Dry Yeast Addition on the Flavor, Metabolites and Antioxidant Properties of Kiwi Wine

by Xiaochen Liu, Lu Lin, Luca Laghi, Gianfranco Picone and Chenglin Zhu

Chemosensors 2025, 13(12), 424; https://doi.org/10.3390/chemosensors13120424 - 6 Dec 2025

Viewed by 327

Abstract

Ultrasonic-assisted maceration and supplementation with glutathione-enriched inactive dry yeast (g-IDY) represent promising strategies to optimize the quality of fermented fruit wines. This study systematically investigated the synergistic effects of combined ultrasonic treatment and g-IDY addition on the metabolomics, flavoromics, and antioxidant properties of [...] Read more.

Ultrasonic-assisted maceration and supplementation with glutathione-enriched inactive dry yeast (g-IDY) represent promising strategies to optimize the quality of fermented fruit wines. This study systematically investigated the synergistic effects of combined ultrasonic treatment and g-IDY addition on the metabolomics, flavoromics, and antioxidant properties of kiwifruit wine (KW), using integrated ¹H-NMR, GC-MS, gas chromatography–ion mobility spectrometry (GC-IMS), and radical scavenging assays. ¹H-NMR analyses revealed that both individual and combined treatments significantly altered the KW metabolome, influencing the levels of amino acids, organic acids, and carbohydrates. GC-MS and GC-IMS analyses characterized numerous volatile compounds, demonstrating that the combined treatments (USL + GSH, USM + GSH, USH + GSH) particularly enhanced the concentrations of desirable fruity esters (e.g., ethyl isobutyrate) and reduced off-flavor compounds (e.g., hexanoic acid), exhibiting a clear synergistic effect beyond individual applications. Furthermore, the combined treatment significantly enhanced the antioxidant capacity of KW, as evidenced by the significantly higher scavenging activities against DPPH, hydroxyl, and superoxide anion radicals, compared to individual applications. Overall, this study sheds light on applying the synergistic treatment of ultrasonics and g-IDY as a novel technique to comprehensively enhance the flavor and functional quality of KW. Full article

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

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17 pages, 6086 KB

Open AccessArticle

Laser-Trimmed, Surface-Functionalized Four-Bore CFMs Enable Co-Detection of Neurochemicals and Toxic Metal Ions

by Navoda Udawaththa, Ashley Daninger, Noel Manring, Valentina Guillen, Gene Koifman and Pavithra Pathirathna

Chemosensors 2025, 13(12), 423; https://doi.org/10.3390/chemosensors13120423 - 6 Dec 2025

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Abstract

Simultaneous detection of multiple neurochemicals and toxic metal ions in real time remains a major analytical challenge in neurochemistry and environmental sensing. In this study, we present a novel, biocompatible, laser-trimmed four-bore carbon fiber microelectrode (CFM) platform capable of ultra-fast, multi-analyte detection using [...] Read more.

Simultaneous detection of multiple neurochemicals and toxic metal ions in real time remains a major analytical challenge in neurochemistry and environmental sensing. In this study, we present a novel, biocompatible, laser-trimmed four-bore carbon fiber microelectrode (CFM) platform capable of ultra-fast, multi-analyte detection using fast-scan cyclic voltammetry (FSCV). Each of the four carbon fibers, spaced nanometers apart within a glass housing, was independently functionalized and addressed with a distinct waveform, allowing the selective and concurrent detection of four analytes without electrical crosstalk. To validate the system, we developed two electrochemical detection paradigms: (1) selective electrodeposition of gold nanoparticles (AuNPs) on one fiber for enhanced detection of cadmium (Cd²⁺), alongside dopamine (DA), arsenic (As³⁺), and copper (Cu²⁺); and (2) Nafion-modification of two diagonally opposing fibers for discriminating DA and serotonin (5-HT) from their interferents, ascorbic acid (AA) and 5-hydroxyindoleacetic acid (5-HIAA), respectively. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis confirmed surface modifications and the spatial localization of electrodeposited materials. Electrochemical characterization in tris buffer, which mimics artificial cerebrospinal fluid, demonstrated enhanced analytical performance. Compared to single-bore CFMs, the four-bore design yielded a 28% increase in sensitivity for Cd²⁺ (147.62 to 190.02 nA µM⁻¹), 12% increase for DA (10.785 to 12.767 nA µM⁻¹), and enabled detection of As³⁺ with a sensitivity of 0.844 nA µM⁻¹, which was not possible with single-bore electrodes within the mixture of analytes. Limits of detection improved twofold for both DA (0.025 µM) and Cd²⁺ (0.005 µM), while As³⁺ was detectable down to 0.1 µM. In neurotransmitter-interference studies, sensitivity increased by 39% for DA and 33% for 5-HT with four-bore CFMs compared to single-bore CFMs, despite modest Nafion diffusion onto adjacent fibers. Overall, our four-bore CFM system enables rapid, selective, and multiplexed detection of chemically diverse analytes in a single scan, providing a highly promising platform for real-time neurochemical monitoring, environmental toxicology, and future integration with AI-based in vivo calibration models. Full article

(This article belongs to the Special Issue Green Electrochemical Sensors for Trace Heavy Metal Detection)

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31 pages, 4361 KB

Open AccessReview

Ionophore-Based Electrochemical Sensors for Metal Ion Detection: Materials, Designs and Applications

by My Thi Ngoc Nguyen, SungHun Cho and Jun Seop Lee

Chemosensors 2025, 13(12), 422; https://doi.org/10.3390/chemosensors13120422 - 5 Dec 2025

Viewed by 525

Abstract

The accurate monitoring of metal ions is essential for applications that include environmental protection, food safety, and biomedical diagnostics. These areas depend on highly sensitive and selective methods for detecting both toxic and biologically relevant ions. Electrochemical sensors have emerged as promising devices [...] Read more.

The accurate monitoring of metal ions is essential for applications that include environmental protection, food safety, and biomedical diagnostics. These areas depend on highly sensitive and selective methods for detecting both toxic and biologically relevant ions. Electrochemical sensors have emerged as promising devices due to their excellent sensitivity, cost-effectiveness, and ease of use. Within these sensor systems, ionophores, either synthetic or natural ligands that exhibit selective ion binding, are fundamental in boosting analytical performance. This review outlines the current progress of ionophore-based electrochemical sensors for metal-ion analysis, emphasizing material selection, architectural strategies, and practical applications. Key classes of ionophores, such as crown ethers, calixarenes, Schiff bases, porphyrins, and oxime derivatives, are discussed with an emphasis on their recognition mechanisms. We also examine strategies for incorporating ionophores into diverse electrochemical sensor configurations and explore recent advances in technologies, such as all-solid-state sensor construction and the development of portable analytical devices. This review bridges the chemistry of ionophores with sensor engineering and serves as a resource for the rational development of advanced platforms for metal-ion sensing. Full article

(This article belongs to the Special Issue Green Electrochemical Sensors for Trace Heavy Metal Detection)

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23 pages, 3726 KB

Open AccessReview

Tracking PFAS Using Nanomaterial-Based Sensors: Limitations, Advances, and Challenges

by Anđela Gavran, Snežana Uskoković-Marković, Bojana Nedić Vasiljević, Aleksandra Janošević Ležaić, Nemanja Gavrilov, Maja Milojević-Rakić and Danica Bajuk-Bogdanović

Chemosensors 2025, 13(12), 421; https://doi.org/10.3390/chemosensors13120421 - 5 Dec 2025

Viewed by 991

Abstract

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are emerging contaminants of global concern, requiring sensitive and highly selective detection methods. Stringent demands imposed by the Environmental Protection Agency, with maximum contaminant levels set at 4.0 parts per trillion for PFAS individually in drinking water, are [...] Read more.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are emerging contaminants of global concern, requiring sensitive and highly selective detection methods. Stringent demands imposed by the Environmental Protection Agency, with maximum contaminant levels set at 4.0 parts per trillion for PFAS individually in drinking water, are the primary driving force behind the development of novel sensors for PFAS. Pushing towards these ultra-low concentrations, however, reaches the limit of what can be reliably detected by field sensors, with PFAS optical and electrochemical inactivity, making it nearly impossible. Molecularly imprinted polymers and immunoassays offer the best chance of developing such sensors as they interact specifically with the active site, changing the optical or electrochemical response (fluorescence, impedance, voltage). Nanoparticulate metal oxides, carbon materials, including carbon dots, polymer coating, and MXenes have been put forward; however, several of these approaches have failed to achieve either the desired limit of detection, sensitivity, or selectivity. Here, we provide an overview of recent progress in nanomaterial-based PFAS sensors, with particular emphasis on strategies to enhance sensitivity, selectivity, and reliability in complex matrices. Finally, we outline key challenges and future perspectives toward robust, field-deployable PFAS sensing technologies. Full article

(This article belongs to the Special Issue Nanomaterials in Chemosensors and Biosensors: Development and Application (2nd Edition))

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37 pages, 1571 KB

Open AccessReview

Molecularly Imprinted Polymer-Based Sensors in Food Contaminants Analysis: Advances, Applications, and Future Trends

by Leina El Hosry and Elias Bou-Maroun

Chemosensors 2025, 13(12), 420; https://doi.org/10.3390/chemosensors13120420 - 5 Dec 2025

Viewed by 760

Abstract

Molecularly Imprinted Polymer (MIP)-based sensors have gained increasing attention in the field of food safety analysis due to their unique ability to selectively recognize and quantify chemical contaminants and allergens with interesting sensitivity. These synthetic receptors, often referred to as “plastic antibodies,” offer [...] Read more.

Molecularly Imprinted Polymer (MIP)-based sensors have gained increasing attention in the field of food safety analysis due to their unique ability to selectively recognize and quantify chemical contaminants and allergens with interesting sensitivity. These synthetic receptors, often referred to as “plastic antibodies,” offer several advantages over conventional analytical methods, including high stability, cost-effectiveness, reusability, and compatibility with miniaturized sensor platforms. This review provides a comprehensive overview of recent advances in the design, fabrication, and application of MIP-based sensors for the detection of a broad range of food contaminants, including pesticides, antibiotics, mycotoxins, heavy metals, acrylamide, heterocyclic amines, allergens, viruses, and bacteria. Various transduction mechanisms—electrochemical, optical, thermal, and mass-sensitive—are discussed in relation to their integration with MIP recognition elements. The review also highlights the advantages and limitations of MIPs in comparison with traditional techniques such as ELISA and HPLC. Finally, we explore current challenges and emerging trends, including nanomaterial integration, multiplexed detection, and smartphone-based platforms, which are expected to drive future developments toward real-time, point-of-need, and regulatory-compliant food safety monitoring tools. Full article

(This article belongs to the Special Issue Molecularly Imprinted Polymer (MIP) Sensors)

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12 pages, 4335 KB

Open AccessArticle

ZnS Nanomaterials with Hexagon and Pentagon Structures: Effect of Surfactants on Surface Morphology and Biosensing Application

by Antony Ananth, Ihn Han, Eun Ha Choi and Jin-Hyo Boo

Chemosensors 2025, 13(12), 419; https://doi.org/10.3390/chemosensors13120419 - 4 Dec 2025

Viewed by 347

Abstract

Zinc sulfide nanomaterials (ZnS NMs) are widely used in many important technological applications, and the performance efficiency is determined by the nanostructure, size, and shape. This indicates that achieving a desirable surface architecture is pivotal for any application. One of the efficient and [...] Read more.

Zinc sulfide nanomaterials (ZnS NMs) are widely used in many important technological applications, and the performance efficiency is determined by the nanostructure, size, and shape. This indicates that achieving a desirable surface architecture is pivotal for any application. One of the efficient and cost-effective techniques, the hydrothermal method, offers uniform size, specific shape, and bulk synthesis capability. This research deals with the preparation of ZnS NMs exhibiting unique surface structures such as spherical, nano-pentagon, and nano-hexagon shapes through employing different zinc precursors and surfactants. The obtained material’s crystal structure was classified as cubic sphalerite and exhibited high purity, as analyzed by XRD, SEM-EDX, TEM, and XPS. Furthermore, the synthesized ZnS NMs were tested for their shape-dependent biosensing application, such as specific antibacterial tests against routine human pathogens such as E. coli, K. pneumoniae, and S. aureus. Several antibacterial methods, such as bacterial colony plate count, growth inhibition analysis, and minimum inhibition concentration (MIC) measurements were carried out. The results confirmed that the antibacterial action in the method employed was dependent on three factors: the NM shape, concentration, and type/nature of bacteria. Especially, the prepared ZnS NMs exhibited excellent antibacterial sensing characteristics, as observed from the lower MIC values in the range of 15.6~250 µg/mL. Full article

(This article belongs to the Special Issue Nanomaterials in Chemosensors and Biosensors: Development and Application (2nd Edition))

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19 pages, 2271 KB

Open AccessArticle

Plasmonic Nanopore Sensing to Probe the DNA Loading Status of Adeno-Associated Viruses

by Scott Renkes, Steven J. Gray, Minjun Kim and George Alexandrakis

Chemosensors 2025, 13(12), 418; https://doi.org/10.3390/chemosensors13120418 - 4 Dec 2025

Viewed by 872

Abstract

Adeno-associated viruses (AAVs) are a leading vector for gene therapy, yet their clinical utility is limited by the lack of robust quality control methods to distinguish between empty (AAV_empty), partially loaded (AAV_partial), and fully DNA loaded (AAV_full) [...] Read more.

Adeno-associated viruses (AAVs) are a leading vector for gene therapy, yet their clinical utility is limited by the lack of robust quality control methods to distinguish between empty (AAV_empty), partially loaded (AAV_partial), and fully DNA loaded (AAV_full) capsids. Current analytical techniques provide partial insights but remain limited in sensitivity, throughput, or resolution. Here we present a multimodal plasmonic nanopore sensor that integrates optical trapping with electrical resistive-pulse sensing to characterize AAV9 capsids at the single-particle level in tens of μL sample volumes and fM range concentrations. As a model system, we employed AAV9 capsids not loaded with DNA, capsids loaded with a self-complementary 4.7 kbp DNA (AAV_scDNA), and ones loaded with single-stranded 4.7 kbp DNA (AAV_ssDNA). Ground-truth validation was performed with analytical ultracentrifugation (AUC). Nanosensor data were acquired concurrently for optical step changes (occurring at AAV trapping and un-trapping) both in transmittance and reflectance geometries, and electrical nanopore resistive pulse signatures, making for a total of five data dimensions. The acquired data was then filtered and clustered by Gaussian mixture models (GMMs), accompanied by spectral clustering stability analysis, to successfully separate between AAV species based on their DNA load status (AAV_empty, AAV_partial, AAV_full) and DNA load type (AAV_scDNA versus AAV_ssDNA). The motivation for quantifying the AAV_empty and AAV_partial population fractions is that they reduce treatment efficacy and increase immunogenicity. Likewise, the motivation to identify AAV_scDNA population fractions is that these have much higher transfection rates. Importantly, the results showed that the nanosensor could differentiate between AAV_scDNA and AAV_ssDNA despite their identical masses. In contrast, AUC could not differentiate between AAV_scDNA and AAV_ssDNA. An equimolar mixture of AAV_scDNA, AAV_ssDNA and AAV_empty was also measured with the sensor, and the results showed the expected population fractions, supporting the capacity of the method to differentiate AAV load status in heterogeneous solutions. In addition, less common optical and electrical signal signatures were identified in the acquired data, which were attributed to debris, rapid entry re-entry to the optical trap, or weak optical trap exits, representing critical artifacts to recognize for correct interpretation of the data. Together, these findings establish plasmonic nanopore sensing as a promising platform for quantifying AAV DNA loading status and genome type with the potential to extend ultra-sensitive single-particle characterization beyond the capabilities of existing methods. Full article

(This article belongs to the Special Issue Electrochemical Sensors Based on Various Materials)

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21 pages, 55903 KB

Open AccessArticle

Spectroscopic Analysis for the Characterization of 3D-Printed Zinc Supplements for Tailored Veterinary Treatment

by Neda Gavarić, Nemanja Todorović, Senka Popović, Ivan Božić, Aleksa Vojnović, Nataša Milošević and Mladena Lalić-Popović

Chemosensors 2025, 13(12), 417; https://doi.org/10.3390/chemosensors13120417 - 4 Dec 2025

Cited by 1 | Viewed by 395

Abstract

Background: Individualized care in veterinary practice optimizes pharmaceutical dose regimens, facilitates disease prevention, and supports animal health by considering the animal’s individual profile. Three-dimensional (3D) printing is a suitable technology for manufacturing both tailored drugs and supplements with enhanced efficacy and reduced adverse [...] Read more.

Background: Individualized care in veterinary practice optimizes pharmaceutical dose regimens, facilitates disease prevention, and supports animal health by considering the animal’s individual profile. Three-dimensional (3D) printing is a suitable technology for manufacturing both tailored drugs and supplements with enhanced efficacy and reduced adverse reactions. Zinc is used to correct deficiencies, support growth, boost the immune system, and treat specific conditions like zinc-responsive dermatosis in dogs. The purpose of the study was to develop and analyze tailored zinc-loaded filaments for the design of custom-made 3D-printed shapes. Methods: Zinc oxide (ZnO) and artificial beef flavor were incorporated into hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC), respectively, to produce tailored 5% or 10% ZnO-containing filaments for 3D printing. The obtained filaments and 3D-printed forms were characterized using sieve analysis, moisture determination, melting point, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction analysis. Results: The characterization of two placebo and four custom-made 3D-printed ZnO supplements suggested that HPMC is a polymer with poor processability, whereas HPC is suitable for incorporating artificial beef flavor and ZnO. FTIR analysis indicated no interaction between the components. Conclusion: The HPC and 10% flavor mixture can be applied as a matrix for manufacturing 3D-printed forms with ZnO for individualized animal care. Full article

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

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15 pages, 4945 KB

Open AccessArticle

Carbon Quantum Dot–Supported Nickel Nanoparticles as a Synergistic Interface for Electrochemical Creatinine Sensing

by Velia Osuna, César Leyva-Porras, Rocio B. Dominguez, Omar Isaac Torres-Soto, Alejando Vega-Rios, Erasto Armando Zaragoza-Contreras and Claudia I. Piñón-Balderrama

Chemosensors 2025, 13(12), 416; https://doi.org/10.3390/chemosensors13120416 - 2 Dec 2025

Viewed by 375

Abstract

We report a non-enzymatic electrochemical sensing platform for creatinine based on a nickel-nanoparticle/carbon-quantum-dot (NiNP–CQD) hybrid interface. In this system, the analytical signal originates from the direct electrocatalytic oxidation of creatinine mediated by the Ni(II)/Ni(III) redox couple (Ni(OH)₂/NiOOH), which forms during electrochemical [...] Read more.

We report a non-enzymatic electrochemical sensing platform for creatinine based on a nickel-nanoparticle/carbon-quantum-dot (NiNP–CQD) hybrid interface. In this system, the analytical signal originates from the direct electrocatalytic oxidation of creatinine mediated by the Ni(II)/Ni(III) redox couple (Ni(OH)₂/NiOOH), which forms during electrochemical activation of nickel in alkaline media. These redox centers act as catalytic sites that oxidize creatinine without requiring enzymes or biomolecular labels. The CQDs provide a conductive sp²-rich network with abundant oxygenated groups that promote homogeneous nucleation and dispersion of NiNPs, enhancing both surface area and electron-transfer efficiency. Electrochemical characterization of the modified electrodes was performed using the ferricyanide/ferrocyanide redox couple as the electron-transfer probe. Structural and microscopic characterization confirms uniform NiNP deposition on the CQD layer, while electrochemical studies demonstrates that the composite outperforms CQDs or NiNPs alone in current density, linearity, and resistance to active-site saturation. The resulting sensor exhibits a wide linear range (10–1000 µM), high area-normalized sensitivity (1.41 µA µM⁻¹ cm⁻²), and a low detection limit of 5 µM. Selectivity tests reveal minimal interference from common physiological species. By explicitly leveraging a catalyst-driven, enzyme-free oxidation pathway, this NiNP–CQD architecture provides a robust, stable, and scalable platform for clinically relevant creatinine detection. Full article

(This article belongs to the Special Issue Nanomaterial-Based Chemosensors and Biosensors for Smart Sensing)

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14 pages, 2234 KB

Open AccessArticle

Silver Nanowires with Efficient Peroxidase-Emulating Activity for Colorimetric Detection of Hydroquinone in Various Matrices

by Huda Salem AlSalem, Sara Naif Alharbi, Rabeea D. Abdel-Rahim, Adham M. Nagiub and Mohamed A. Abdel-Lateef

Chemosensors 2025, 13(12), 415; https://doi.org/10.3390/chemosensors13120415 - 1 Dec 2025

Viewed by 434

Abstract

Hydroquinone is a phenolic compound widely used in industry and cosmetics, yet its toxicity has raised global environmental and health concerns. It has been listed by both the US EPA and the European Union as a priority contaminant for monitoring in aquatic systems. [...] Read more.

Hydroquinone is a phenolic compound widely used in industry and cosmetics, yet its toxicity has raised global environmental and health concerns. It has been listed by both the US EPA and the European Union as a priority contaminant for monitoring in aquatic systems. In this proof-of-concept (PoC) study, silver nanowires (Ag-NWs) were synthesized via a modified one-pot polyol methodology and characterized by various techniques, including TEM, EDX, SEM, XRD, and UV–vis spectroscopy. The Ag-NWs exhibited peroxidase-like activity, catalyzing the oxidation of TMB/H₂O₂ to yield a blue product. This activity was effectively suppressed by hydroquinone, forming the basis of a simple colorimetric sensing approach. The PoC method showed linearity over 0.08–0.8 µg/mL with a LOD of 26 ng/mL. Furthermore, it was preliminarily applied to tap water, river water, and medicated cream samples, demonstrating acceptable recovery in preliminary applications. As a PoC, the study establishes the feasibility of the Ag-NWs–TMB–H₂O₂ system for hydroquinone detection, while recognizing that comprehensive reproducibility assessment and temporal stability evaluation are required in future work. Full article

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

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21 pages, 1884 KB

Open AccessArticle

From Bench to Bedside: Validation of an ELISA Analytical Method for the Determination of Ricin in Biological Samples and Clinical Data on Related Intoxications

by Antonella Rotolo, Martina Pes, Giovanni Solarino, Elisa Roda, Azzurra Schicchi, Davide Lonati, Filippo Uberti, Carlo A. Locatelli and Daniele Merli

Chemosensors 2025, 13(12), 414; https://doi.org/10.3390/chemosensors13120414 - 1 Dec 2025

Viewed by 526

Abstract

Accidental and deliberate poisoning by Ricinus communis, a wild plant cultivated for castor oil, has been known for centuries. Seeds contain one of the deadliest known plant toxins, ricin, along with its dimer RCA120. Due to its toxicity and ease of extraction, [...] Read more.

Accidental and deliberate poisoning by Ricinus communis, a wild plant cultivated for castor oil, has been known for centuries. Seeds contain one of the deadliest known plant toxins, ricin, along with its dimer RCA120. Due to its toxicity and ease of extraction, ricin poses a potential threat as a chemical weapon, highlighting the need for reliable laboratory detection. In this work, ricin and RCA120 (Ricinus communis agglutinin) were extracted from castor beans and purified by solid-phase extraction (SPE) and Gel Permeation Chromatography (GPC). Purity was confirmed through Sodium Dodecyl Sulphate-PolyAcrylamide Gel Electrophoresis (SDS-PAGE). Then, lab-made standards were used to validate an Enzyme Linked ImmunoSorbent Assay (ELISA) kit to identify ricin in biological matrices after SPE extraction. Parallelly, SDS-PAGE was used to qualitatively confirm the presence of toxins. The developed method demonstrated a detection limit (LOD) of 2.74 ng/mL and was used to analyse biological specimens of seven human intoxication cases managed by Pavia Poison Control Centre (PCC). This study provides a quiet, inexpensive protocol that within 5 h allows the screening of potential ricin-exposure victims. Its implementation in clinical laboratories could support the management of intoxicated patients, ensuring faster and more accurate clinical response. Full article

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

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11 pages, 1721 KB

Open AccessArticle

Hemicyanine-Based Fluorescent Probes for Cysteine Detection in Cellular Imaging and Food Samples

by Wenqi Jiang, Quanping Diao, Weiwei Luo, Linlin Lv, Tiechun Li, Qingwang Min, Jinxiu Bing and Majie Zhang

Chemosensors 2025, 13(12), 413; https://doi.org/10.3390/chemosensors13120413 - 1 Dec 2025

Viewed by 407

Abstract

Cysteine (Cys) is an essential thiol in food and biological systems, yet its selective quantification remains challenging due to interference from structurally related analytes such as homocysteine (Hcy) and glutathione (GSH). Here, we report a hemicyanine-based, turn-off fluorescent probe (PRH) that undergoes Cys-triggered [...] Read more.

Cysteine (Cys) is an essential thiol in food and biological systems, yet its selective quantification remains challenging due to interference from structurally related analytes such as homocysteine (Hcy) and glutathione (GSH). Here, we report a hemicyanine-based, turn-off fluorescent probe (PRH) that undergoes Cys-triggered cyclization to release PRH-OH, resulting in fluorescence quenching. PRH exhibits near-infrared emission at 630 nm, enabling low self-absorption and reduced background. The probe affords a broad linear range (0–100 μM) with a detection limit of 0.344 μM, along with high selectivity over Hcy, GSH, and 18 other amino acids. In food matrices (garlic, onion, and dried red pepper), PRH achieved recoveries of 98.8–101.3% with RSD < 2% (n = 3), demonstrating analytical robustness. Live-cell imaging in HeLa cells further verified practical responsiveness: N-ethylmaleimide-mediated thiol depletion increased PRH fluorescence, whereas Cys replenishment decreased it, consistent with the probe’s turn-off behavior. DFT calculations support an intramolecular charge-transfer change upon Cys reaction, correlating with the observed spectral shift. Overall, PRH provides a simple and selective platform for reliable Cys quantification in food samples and for visualizing Cys dynamics in cells. Full article

(This article belongs to the Section Optical Chemical Sensors)

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15 pages, 1541 KB

Open AccessArticle

Using pH Value as a Discriminating Feature for Scotch Whisky Authentication in Taiwan

by Ting-Chia Chang, Min-You Wu, Hsiao-Wen Huang and Wei-Tun Chang

Chemosensors 2025, 13(12), 412; https://doi.org/10.3390/chemosensors13120412 - 30 Nov 2025

Viewed by 615

Abstract

While pH possesses inherent chemical significance and potential forensic value in Scotch whisky authentication, it has previously lacked a statistically rigorous exclusionary standard. This study addressed this gap by performing statistical distribution fitting analysis on the pH of 32 authentic single malt and [...] Read more.

While pH possesses inherent chemical significance and potential forensic value in Scotch whisky authentication, it has previously lacked a statistically rigorous exclusionary standard. This study addressed this gap by performing statistical distribution fitting analysis on the pH of 32 authentic single malt and 33 authentic blended Scotch whiskies, utilizing the three-parameter lognormal distribution to establish the 99.7% authentic pH ranges for the first time: 3.47–4.46 for single malt and 3.73–4.67 for blended whisky. Validation using seized counterfeit samples confirmed that an abnormally elevated pH serves as critical evidence of adulteration. Consequently, this research proposes the chemically fundamental pH threshold as a rapid, non-destructive, and cost-effective forensic exclusionary criterion. Although the pH value feature alone is insufficient to confirm authenticity, its high operational applicability significantly enhances the efficiency of rapid field screening for counterfeit whisky, strongly supporting law enforcement and food safety efforts in Taiwan. Full article

(This article belongs to the Special Issue Sensors for Food Testing, Environmental Analysis, and Medical Diagnostics)

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36 pages, 5230 KB

Open AccessReview

Organic Field-Effect Transistor Biosensors for Clinical Biomarkers: Materials, Architectures, and Translational Applications

by Joydip Sengupta, Arpita Adhikari and Chaudhery Mustansar Hussain

Chemosensors 2025, 13(12), 411; https://doi.org/10.3390/chemosensors13120411 - 30 Nov 2025

Viewed by 796

Abstract

Organic field-effect transistor (OFET) biosensors have emerged as a transformative technology for clinical biomarker detection, offering unprecedented sensitivity, selectivity, and versatility in point-of-care (POC) diagnostics. This review examines the fundamental principles, materials innovations, device architectures, and clinical applications of OFET-based biosensing platforms. The [...] Read more.

Organic field-effect transistor (OFET) biosensors have emerged as a transformative technology for clinical biomarker detection, offering unprecedented sensitivity, selectivity, and versatility in point-of-care (POC) diagnostics. This review examines the fundamental principles, materials innovations, device architectures, and clinical applications of OFET-based biosensing platforms. The unique properties of organic semiconductors, combined with advanced biorecognition strategies, enable the detection of clinically relevant biomarkers at low concentrations. Recent developments in organic semiconductor materials have significantly enhanced device performance and stability. The integration of novel device architectures such as electrolyte-gated OFETs (EGOFETs) and extended-gate configurations has expanded the operational capabilities of these sensors in aqueous environments. Clinical applications span a broad spectrum of biomarkers, demonstrating the versatility of OFET biosensors in disease diagnosis and monitoring. Despite remarkable progress, challenges remain in terms of long-term stability, standardization, and translation to clinical practice. The convergence of organic electronics, biotechnology, and clinical medicine positions OFET biosensors as a promising platform for next-generation personalized healthcare and precision medicine applications. Full article

(This article belongs to the Special Issue Recent Advances in Field-Effect Transistor-Based Sensors)

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12 pages, 1430 KB

Open AccessArticle

Development of a Flatbed Scanner-Based Colorimetric Method for the Indirect Determination of Fluoride Ions Using 96-Well Plates in Oral Hygiene Products

by Chrysanthi Galenteridi, Maria Tarara, Paraskevas D. Tzanavaras and George Z. Tsogas

Chemosensors 2025, 13(12), 410; https://doi.org/10.3390/chemosensors13120410 - 29 Nov 2025

Viewed by 404

Abstract

An indirect, novel, fast, and facile assay was developed for the colorimetric determination of fluoride anions using 96-well plates. The proposed method relies on the colorimetric degradation caused by fluoride ions after their reaction with the iron–thiocyanate complex in an acidic medium. The [...] Read more.

An indirect, novel, fast, and facile assay was developed for the colorimetric determination of fluoride anions using 96-well plates. The proposed method relies on the colorimetric degradation caused by fluoride ions after their reaction with the iron–thiocyanate complex in an acidic medium. The procedure required the addition of minimal amounts of ferric iron and thiocyanate anion solutions to form the corresponding complex with an intense blood-red color, after which, upon addition of fluoride ions, this complex would dissociate, and its color would gradually fade depending on the analyte concentration. The colorimetric differences were measured using a simple imaging device such as a flatbed scanner. Various parameters affecting the analytical performance of the proposed method were optimized, including solution concentrations, pH values, and reaction time for Fe(III)-SCN complex formation and its disintegration process. The proposed assay was successfully applied to the determination of F⁻ in oral hygiene product samples. The method exhibited acceptable detection limits (3.2 mg L⁻¹) with sufficient precision, good intra-day and inter-day reproducibility (ranging from 1.5 to 5.2%), and high selectivity against other anions and components of the samples under study. Full article

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

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16 pages, 892 KB

Open AccessArticle

Comparison of PLSR and PCR Models for Estimating Time Since Deposition of Human Saliva Stains Using ATR-FTIR Spectroscopy Under Simulated Crime Conditions

by Antonio José Perán-Orcajada, Miguel Mengual-Pujante, Antonio Ortiz and Maria D. Pérez-Cárceles

Chemosensors 2025, 13(12), 409; https://doi.org/10.3390/chemosensors13120409 - 29 Nov 2025

Viewed by 412

Abstract

Saliva is a biological fluid that can be found at various crime scenes and mainly presents two challenges for the forensic analysis: its identification and the estimation of the time since deposition (TSD). In this study, the performance of Partial Least Squares Regression [...] Read more.

Saliva is a biological fluid that can be found at various crime scenes and mainly presents two challenges for the forensic analysis: its identification and the estimation of the time since deposition (TSD). In this study, the performance of Partial Least Squares Regression (PLSR) and Principal Component Regression (PCR) models is compared for estimating the TSD of human saliva stains using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Saliva samples were obtained from eight donors and deposited on various surfaces, exposed to different environmental conditions (indoor and outdoor) and analyzed over a period ranging from 0 to 212 days. The results indicate that PLSR outperforms PCR in terms of Root Mean Squared Error (RMSE) in all cases. This improvement is particularly evident on paper surfaces, where PLSR reduces the RMSE by 10.45 days under indoor conditions and by 13.47 days under outdoor conditions compared to PCR. On woven surfaces, PLSR improves the RMSE by 3.19 days under indoor conditions and by 8.27 days under outdoor conditions compared to PCR. These results highlight the potential of vibrational spectroscopy combined with chemometric methods for the in situ forensic analysis of biological fluids at crime scenes. Full article

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

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15 pages, 3043 KB

Open AccessArticle

Detection of Olive Oil Adulteration with Corn Oil Based on the Phenolic Compounds Profile Obtained by UHPLC-MS/MS

by Elisabeta-Irina Geana, Irina Mirela Apetrei and Constantin Apetrei

Chemosensors 2025, 13(12), 408; https://doi.org/10.3390/chemosensors13120408 - 27 Nov 2025

Viewed by 534

Abstract

Unrefined vegetable oils are an important source of bioactive compounds with beneficial effects on health. Therefore, confirming the biological identity of oils is important for ethical and economic reasons. In this study, a method was developed for discriminating vegetable oils based on the [...] Read more.

Unrefined vegetable oils are an important source of bioactive compounds with beneficial effects on health. Therefore, confirming the biological identity of oils is important for ethical and economic reasons. In this study, a method was developed for discriminating vegetable oils based on the phenolic compounds profile obtained by ultrahigh-performance liquid chromatography-mass spectrometry (UHPLC-MS/MS). It was found that extra virgin olive oil has a cinnamic acid content of 2.2 mg/kg (mean value), a much higher value compared to other oils (not detected—0.4 mg/kg), thus being a representative phenolic marker for this oil. From the phenolic compounds profile of different vegetable oils, it can be stated that extra virgin olive oil has a specific phenolic content. However, walnut, sunflower, and corn oils have some similarities regarding the phenolic compounds content (for instance, ellagic acid) and, therefore, these oils can be used as adulterants of extra virgin olive oil. Data analysis, including principal component analysis, hierarchical cluster analysis, and partial least-squares discriminant analysis, demonstrated the discrimination of olive oils from other vegetable oils. Data analysis also allowed the discrimination and classification of olive oil samples adulterated with corn oil when the percentage of adulterant was 1%, with an accuracy of more than 90%. Full article

(This article belongs to the Special Issue Spectroscopy, Imaging and Chemometric Modelling for Quality Analysis in Food and Drug Research)

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19 pages, 8013 KB

Open AccessArticle

XPS Study of Nanostructured Pt Catalytic Layer Surface of Gas Sensor Dubbed GMOS

by Hanin Ashkar, Sara Stolyarova, Tanya Blank and Yael Nemirovsky

Chemosensors 2025, 13(12), 407; https://doi.org/10.3390/chemosensors13120407 - 24 Nov 2025

Cited by 1 | Viewed by 511

Abstract

The long-term reliability of catalytic gas sensors is strongly influenced by changes in the chemical state and cleanliness of the catalyst surface. In this work, we investigate the surface composition and stability of the platinum (Pt) nanoparticle catalytic layer in Gas Metal-Oxide-Semiconductor (GMOS) [...] Read more.

The long-term reliability of catalytic gas sensors is strongly influenced by changes in the chemical state and cleanliness of the catalyst surface. In this work, we investigate the surface composition and stability of the platinum (Pt) nanoparticle catalytic layer in Gas Metal-Oxide-Semiconductor (GMOS) sensors under varying environmental conditions. Using X-ray Photoelectron Spectroscopy (XPS) and High-Resolution (HR) XPS, we compared fresh, aged samples, thermally treated samples, and samples stored with or without a mechanical filter. The results show that prolonged ambient storage leads to the accumulation of adventitious carbon and nitrogen-containing species, as well as partial oxidation of platinum, which reduces the number of active metallic Pt sites. Thermal treatment at 300 °C for 30 min restores metallic Pt exposure by removing surface contaminants and narrowing the Pt 4f peaks. However, recontamination occurs during subsequent storage, with significant differences depending on surface protection. Sensors equipped with a mechanical filter exhibited obvious Pt metallic peaks in HR-XPS analysis, with lower carbon and nitrogen levels, compared to unprotected samples. These findings demonstrate that while heating refreshes catalytic activity, long-term stability requires complementary filtration to prevent re-adsorption of airborne species. The combined approach of heating and filtration is thus essential to ensure reliable performance of GMOS sensors for indoor and outdoor air quality monitoring. Full article

(This article belongs to the Special Issue Innovative Nanomaterials-Based Chemosensor Devices for Air Quality Monitoring)

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19 pages, 2179 KB

Open AccessArticle

Assay of Two Antibacterial/Anticoccidial Drugs in Combination with Vitamin K3 for Oral Solutions: Stability Studies and Method Development Using HPLC-DAD: Appraisal of the Method’s Eco-Friendliness and Functionality

by Lateefa A. Al-Khateeb, Mohamed Ahmed Elsayed, Rehab Moussa Tony and Mohammed Gamal

Chemosensors 2025, 13(12), 406; https://doi.org/10.3390/chemosensors13120406 - 24 Nov 2025

Viewed by 587

Abstract

A novel, green, stability-illustrating HPLC-DAD method was validated for the simultaneous analysis of menadione (MND), dimetridazole (DMT), and sulfadimethoxine sodium (SLF) in a veterinary powder for the first time. These compounds are commonly combined in veterinary premixes and powders to enhance animal growth, [...] Read more.

A novel, green, stability-illustrating HPLC-DAD method was validated for the simultaneous analysis of menadione (MND), dimetridazole (DMT), and sulfadimethoxine sodium (SLF) in a veterinary powder for the first time. These compounds are commonly combined in veterinary premixes and powders to enhance animal growth, prevent bacterial infections, and improve feed efficiency. Separation was achieved isocratically on a C18 column using a mobile phase of 0.05M KH₂PO₄: acetonitrile (80:20, v/v) at a flow rate of 2.0 mL/min, with detection at 260 nm. The represented HPLC-DAD method was rapid, yielding retention times under 5.2 min, and exhibited excellent linearity over the tested ranges (10.0–30.0, 20.0–60.0, and 20.0–60.0 µg/mL for MND, DMT, and SLF, respectively). Forced degradation studies, conducted according to the International Council for Harmonisation (ICH) guidelines, confirmed the method’s specificity in distinguishing the active pharmaceutical ingredients from their degradation products. The highest degradation was observed for MND (photolytic, 26.52%), DMT (alkaline, 21.12%), and SLF (oxidative, 27.16%). The method’s environmental sustainability was evaluated using the Analytical GREEnness (AGREE) metric (score: 0.75) and the Green Analytical Procedure Index (GAPI), while its practicality was supported by a high Blue Applicability Grade Index (BAGI) score of 80.0. This stability-indicating method represents the first robust, green, and reliable analytical approach for this triple veterinary formulation. Full article

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

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12 pages, 718 KB

Open AccessArticle

A Simplified Multi-Residue Method Using μSPE Clean-Up Combined with Gas Chromatography-High Resolution Mass Spectrometry for the Determination of 250 Pesticide Residues in Cow’s Milk

by Marta Vargas-Pérez, Osmar D. Prestes, Roberto Romero-González and Antonia Garrido Frenich

Chemosensors 2025, 13(12), 405; https://doi.org/10.3390/chemosensors13120405 - 22 Nov 2025

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Abstract

The complexity of the milk matrix, driven by its lipid-rich composition, complicates pesticide residue analysis. This study developed a simplified and robust analytical procedure for the quantification of 250 pesticides in cow’s milk. Sample preparation involved acidified ethyl acetate extraction followed by centrifugation [...] Read more.

The complexity of the milk matrix, driven by its lipid-rich composition, complicates pesticide residue analysis. This study developed a simplified and robust analytical procedure for the quantification of 250 pesticides in cow’s milk. Sample preparation involved acidified ethyl acetate extraction followed by centrifugation at 0 °C. A subsequent clean-up step was performed using micro solid-phase extraction (μSPE) in a 96-well format with the enhanced matrix removal-lipid (EMR-lipid) sorbent. Final extracts were analyzed by gas chromatography coupled to high-resolution mass spectrometry (GC-Q-Orbitrap-MS). Method validation demonstrated satisfactory linearity within the 5–100 µg/L range, recoveries between 70.6% and 119.8%, and precision, expressed as relative standard deviation (RSD), was acceptable for both intraday (1.8–19.2%) and interday (1.6–18.5%) conditions. The limit of quantification (LOQ) was set at 10 µg/kg for all compounds. The method was applied to 23 commercial cow’s milk samples, and no pesticide residues were detected above the current European Union (EU) maximum residue limits (MRLs). Full article

(This article belongs to the Topic Application of Chromatography-Mass Spectrometry and Related Techniques, 2nd Edition)

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