Detection Of Broad Range Research Articles

All-solid-state electrochemical marine sensors based on Na3V2(PO4)3@Na4Zr2Si3O12 solid-state reference electrodes

In this study, Na4Zr2Si3O12 (NZS) solid electrolyte was prepared using an elevated-temperature solid-state method. After heating under supercritical conditions (i.e., 400 °C and 40 MPa), the structure and performance stability of the as-fabricated NZS solid electrolyte were evaluated applying scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). A new all-solid-state reference electrode, combining Na3V2(PO4)3(NVP) with NZS (NVP@NZS), was developed, and its electrochemical properties were investigated. The prepared reference electrode demonstrated steady potential in both simulated seawater and buffer solutions across a range of pH values and different salt solutions. The reference electrode, integrated with an Ir/IrO2 working electrode, was used to construct an all-solid-state potentiometric pH sensor. This sensor demonstrated a strong linear related response when measuring the pH of both aqueous solutions and simulated seawater samples. Additionally, an ion sensor based on anodic stripping voltammetry, constructed with the assembled solid-state reference electrode, a platinum counter electrode, and a gold-mercury working electrode, was utilized to measure Cu2+ and S2− ions in both aqueous solutions and simulated seawater samples. These all-solid-state electrochemical sensors, incorporating the NVP@NZS solid-state reference electrode, demonstrated a small detection threshold, excellent linear correlation (R2 > 0.99), and a broad detection range, making them well-suited for chemical analysis in challenging marine environments.

Double network hydrogel confined MXene/Liquid metal by dynamic hydrogen bond for high-performance wearable sensors

Double-network (DN) hydrogels, which integrate long-chain and short-chain molecular structures, exhibit significant potential in wearable sensors due to their exemplary mechanical properties. However, conventional hydrogels often suffer from poor conductivity and low sensitivity. In this study, we develop a novel DN hydrogel (comprising polyacrylamide/sodium alginate) that encapsulates MXene (Ti3C2Tx) and liquid metal (LM). This configuration leverages the conductive properties of two-dimensional MXene and zero-dimensional liquid metal embedded within the DN hydrogel networks. The Ti3C2Tx MXene sheets enhance the binding capacity with LM by serving as a conductive bridge, thereby improving interfacial interactions and reducing hysteresis. The resultant strain sensor, fabricated from this composite DN hydrogel, achieves high sensitivity (gauge factor up to 12.84), a broad detection range (0 %-1500 %), rapid response time (262 ms), and excellent repeatability and stability. We have integrated this strain sensor into wearable flexible devices, such as contact lenses, enabling real-time monitoring of human physiological pressures.

Highly Sensitive Electrochemical Detection of Chlorpromazine Using Broccoli‐Like Copper–Aluminum‐Layered Double Hydroxide‐Modified Platinum Electrode

AbstractChlorpromazine (CPZ), an antipsychotic drug derived from phenothiazine, can cause a range of adverse effects in humans, notably visual problems and hematological disorders upon consumption of chlorpromazine‐contaminated water. In this regard, a novel electrochemical sensing platform based on a copper–aluminum‐layered double hydroxide (Cu–Al LDH)‐modified platinum electrode for the highly sensitive and selective detection of chlorpromazine in groundwater samples has been developed. The immobilized Cu–Al LDH showed an electrocatalytic effect on chlorpromazine reduction and oxidation. Among the employed electroanalytical techniques, only the square‐wave voltammetry‐assisted Pt/Cu–Al LDH electrode could detect chlorpromazine with a remarkable sensitivity of 0.065 µA µM−1 over a broad linear detection range of 0.01–760 µM, with low detection and quantification limits of 4.86 and 16.18 nM, respectively. Furthermore, the developed electrode can rapidly detect chlorpromazine within less than 10 s. In addition, the diffusion profiles of steady‐state concentrations of oxidized and reduced chlorpromazine within the immobilized Cu–Al were studied using the Legendre wavelet method. Moreover, the developed Pt/Cu–Al LDH electrode demonstrated satisfactory rates in the quantification of chlorpromazine in groundwater samples, yielding satisfactory recovery rates (97.63–102.57%), confirming the practicability of the fabricated electrode in real‐time monitoring of chlorpromazine levels in groundwater without requiring any sample pretreatment.

Plasmon-Enhanced Photoelectrochemistry of Photosystem II on a Hierarchical Tin Oxide Electrode for Ultrasensitive Detection of 17β-Estradiol.

Despite its excellent efficiency in natural photosynthesis, the utilization of photosystem II (PSII)-based artificial photoelectrochemical (PEC) systems for analytical purposes is hindered due to the low enzyme loading density and ineffective electron transfer (ET) processes. Here, we present a straightforward and effective approach to prepare a PSII-based biohybrid photoanode with remarkable photoresponse, enabled by the use of a hierarchically structured inverse-opal tin oxide (IO-SnO2) electrode combined with gold nanoparticles (Au NPs). The porous, carbon-containing IO-SnO2 structure allows for a high density and photoactivity loading of PSII complexes, while also providing strong electrical coupling between the protein film and the electrode. A new electron transfer pathway mediated by Au NPs was identified at the protein-electrode interface, which efficiently shuttles the photogenerated electrons from the enzyme to the IO-SnO2 electrode. Furthermore, the PEC response of the electrode was significantly enhanced by the surface plasmon resonance (SPR) effect of Au NPs. Upon light irradiation, this PSII-based photoanode exhibited an impressively high and stable photocurrent output, which was utilized to fabricate an aptasensor for 17β-Estradiol (E2) detection. Under optimal conditions, a detection limit of 0.33 pM was obtained, along with a broad detection range from 15 pM to 30 nM. The applicability of the aptasensor was assessed by measuring E2 in water and urine samples, demonstrating its feasibility in environmental monitoring and clinical tests.

High-performance ratiometric magnetic electrochemical sensor for acetamiprid detection using Ag@PDA@Fe3O4 nanocomposites

Acetamiprid (AAP) is a renowned neonicotinoid insecticide for swift insect control that is prone to residue in agricultural products and threatens human health. Magnetic electrochemical sensor (MES) was developed for high-precision detection of AAP based on silver nanoparticle (AgNPs) and polydopamine (PDA) modified Fe3O4 nanocomposites (Ag@PDA@Fe3O4). The electrochemical signals generated by AAP hydrolysis and AgNPs oxidation are respectively used as two special signal sources. An increase in AAP concentration led to a proportional increase in the signal from AAP hydrolysis at +0.9 V (IAAP), while the signal from AgNPs oxidation at +0.27 V (IAg) correspondingly decreased. The output signal ΔIAAP/ΔIAg (R2=0.9890) demonstrates a superior linear relationship compared to ΔIAAP (R2=0.9790) or ΔIAg (R2=0.9740) alone. MES demonstrated a broad linear detection range from 0.01 to 2.00 mg L−1 and an impressive limit of detection (LOD, 3S/M) at 3.6 µg L−1. The incorporation of magnetic glassy carbon electrodes (MGCE) significantly mitigates the detachment of nanomaterials. MES has excellent stability and selectivity, and can successfully detect AAP in actual cowpea samples. This study provides pivotal insights into the design of nanomaterial-based ratiometric electrochemical sensors for the sensitive and selective detection of AAP.

Structural optimization, characterization, and evaluation ofbinding mechanism of aptamers against bovine pregnancy-associated glycoproteins and their application in establishment of a colorimetric aptasensor using Fe-based metal-organic framework as peroxidase mimic tags.

Atruncated aptamer (designated A24-3) was identifiedthat specifically binds to bovine pregnancy-associated glycoproteins (bPAG9) with a low dissociation constant (2.04nM) through two truncation approaches. Circular dichroism spectroscopy indicated that A24-3 formed parallel G-quadruplexes, which was subsequently confirmed using nuclear magnetic resonance (NMR) spectroscopy. Furthermore, a molecular dynamics simulation was employed to investigate the recognition mechanism of A24-3 and bPAG9. Interaction analysis showed that A24-3 folded into a parallel G-quadruplex structure with three G-tetrads, primarily through numerous hydrogen bonds and hydrophobic and π-π interactions. Finally, a novel colorimetric aptasensor was developed for detecting bPAG9 using A24-3 and an Fe-based metal-organic framework as target recognition elements and enzyme mimics, respectively. The method demonstrated a broad detection range from 0.5 to 50ng/mL, with a low detection limit of 0.03ng mL-1, and exhibited a good recovery (91.0-102%) for bPAG9-spiked serum samples. Additionally, the aptasensor was successfully applied todetecting the pregnancy-specific biomarker bPAGs in serum samples.

A Novel Carbon Dot-Bromothymol Blue System for Ratiometric Colorimetric-Fluorometric Sensing of Glutathione in Urine: A Smartphone-Compatible Approach.

This study presents a novel dual-modal approach for glutathione (GSH) detection using blue and yellow dual-emission carbon dots (BY-CDs) and bromothymol blue (BTB) at pH 8.0. The method employs both colorimetric and fluorometric detection modes, offering a new perspective on GSH quantification. BTB's blue coloration induces selective fluorescence quenching of the CDs' 610nm emission peak, with minimal effect on the 445nm peak. Upon GSH addition, the quinonoid structure (blue color) of BTB transforms to its benzenoid form (yellow color). This transformation triggers fluorescence restoration at 610nm and significant quenching at 445nm, enabling ratiometric fluorescence analysis (F610/F445). Concurrently, colorimetric detection is also ratiometric, based on measuring the ratio between the emerging yellow color peak (435nm) and the decreasing blue color peak (618nm) (A435/A618). The state-of-the-art aspect of this detection method lies in the strategic choice of dual-emission CDs and a dye with distinct absorption spectra that closely match the emission spectra of the CDs. This unique combination allows for dual detection with opposite responses in the two detection modes, enhancing selectivity and reliability. The probe was thoroughly characterized, and its detection mechanism was elucidated using various spectroscopic techniques. The method shows excellent linearity, a broad detection range, and low detection limits for both fluorometry (0.02 - 10.0μM, 5.88nM) and colorimetry (1.0 - 35.0μM, 301.25nM). Additionally, a smartphone-based platform was developed for colorimetric GSH determination, enhancing the method's potential for on-site analysis. The assay's practicality was validated through successful application to human urine samples, yielding excellent recovery values (97.33% to 99.13%).

The Promise of Carbon Nano‐Onions: Preparation, Characterization and Their Application in Electrochemical Sensing

AbstractCarbon nano‐onions (CNOs) promise to improve the range of applications of carbon materials for electroanalytical applications. In this review, we explore the synthesis, characterization, and electrochemical applications of CNOs. CNO‐based sensors present impressive features, including low detection limits in the femtogram per milliliter range, a broad linear detection range spanning up to 7 orders of magnitude, exceptional selectivity, reproducibility, and stability. Synthetic methods and characterization techniques for CNOs were thoroughly examined, shedding light on their pivotal role in biosensing technologies. Comparative analyses with other carbon materials underscore CNOs′ competitive performance, either surpassing or matching many counterparts. Despite their relatively recent integration in biosensing applications, CNOs exhibit comparable or superior results concerning other carbon‐based materials. Indeed, the incorporation of CNOs into hybrid nanocomposites has shown promising outcomes, indicating a synergistic potential for future advancements in biosensing technologies. Our review provides a broad approach to the application of CNOs to the field, with emphasis on breakthroughs of the last 5 years.

Instantaneous Tiltmeter Triggered by Dynamic Wetting Behavior.

A novel instantaneous tiltmeter with dynamic and static monitoring functions is reported that is based on liquid metal dynamic wetting behavior in a bio-fabricated anisotropic microchannel. The proposed system achieves instantaneous tiltmeter functionality, offering a broad detection range (-90°-90°) with high precision (0.05°), a rapid reaction time (0.11 s), and enhanced durability. Moreover, a seamless integration has enabled water wave detection, language programming, and human limb monitoring. Especially, the integration of tiltmeter and a t3D motion platform results in a surface structure scanning system capable of effectively performing large area (>200 cm2) and height difference scanning functions. This innovative approach holds great potential for transformative changes in the fields of advanced manufacturing, flexible robotics, and the flexible sensing, further facilitating widespread adoption.

High Performance H2S Sensor Based on Ordered Fe2O3/Ti3C2 Nanostructure at Room Temperature.

The utilization of a heterogeneous nanojunction design has shown significant enhancements in the gas sensing capabilities of traditional metal oxide gas sensors. In this study, a novel room temperature H2S gas sensor employing Fe2O3 functionalized Ti3C2 MXene as the sensing material has been developed. This sensor exhibits a broad detection range (0.01-500 ppm), low detection limit (10 ppb), and rapid response/recovery times (10 s/15 s), making it ideal for ppb-level H2S detection. The exceptional gas sensitivity of Fe2O3/Ti3C2 composite to H2S can be attributed to several key factors. First, the unique layered frame structure of Fe2O3/Ti3C2 significantly amplifies the surface area of the hybrid material, enhancing the absorption and diffusion capabilities of H2S molecules. Second, the abundance of functional groups (-O, -OH, and -F) on the surface of Ti3C2 MXene nanosheets provides additional active sites for H2S adsorption, The density functional theory calculation confirms that the adsorption energy of the Fe2O3/Ti3C2 composite for H2S (-2.93 eV) is significantly lower than that of pure Fe2O3 (-2.37 eV) and Ti3C2 (-0.2 eV). Lastly, the remarkable metal conductivity of Ti3C2 MXene ensures efficient electron transfer, thereby enhancing overall sensing performance.

A Metal-Organic Framework-Based Colorimetric Sensor Array for Transcutaneous CO2 Monitoring via Lensless Imaging

Transcutaneous carbon dioxide (TcPCO2) monitoring provides a non-invasive alternative to measuring arterial carbon dioxide (PaCO2), making it valuable for various applications, such as sleep diagnostics and neonatal care. However, traditional transcutaneous monitors are bulky, expensive, and pose risks such as skin burns. To address these limitations, we have introduced a compact, cost-effective CMOS imager-based sensor for TcPCO2 detection by utilizing colorimetric reactions with metal–organic framework (MOF)-based nano-hybrid materials. The sensor, with a colorimetric sensing array fabricated on an ultrathin PDMS membrane and then adhered to the CMOS imager surface, can record real-time sensing data through image processing without the need for additional optical components, which significantly reduces the sensor’s size. Our system shows impressive sensitivity and selectivity, with a low detection limit of 26 ppm, a broad detection range of 0–2% CO2, and strong resistance to interference from common skin gases. Feasibility tests on human subjects demonstrate the potential of this MOF-CMOS imager-based colorimetric sensor for clinical applications. Additionally, its compact design and responsiveness make it suitable for sports and exercise settings, offering valuable insights into respiratory function and performance. The sensing system’s compact size, low cost, and reversible and highly sensitive TcPCO2 monitoring capability make it ideal for integration into wearable devices for remote health tracking.

Visual signal transduction for environmental stewardship: A novel biosensing approach to identify and quantify chlorpyrifos-related residues in aquatic environments

The pervasive presence of organophosphate pesticides (OPs), such as chlorpyrifos (CPF), in aquatic ecosystems underscores the urgent need for sensitive and reliable detection methods to safeguard environmental and public health. This study addressed the critical need for a novel biosensor capable of detecting CPF and its toxic metabolite, 3,5,6-trichloro-2-pyridinol (TCP), with high sensitivity and selectivity, suitable for field applications in environmental monitoring. The study engineered a whole-cell biosensor based on E. coli strains that utilize the ChpR transcriptional regulator and the vioABCE gene cluster, providing a distinct visual and colorimetric response to CPF and TCP. The biosensor's performance was optimized and evaluated across various water matrices, including freshwater, seawater, and soil leachate. The biosensor demonstrated high sensitivity with a broad linear detection range, achieving limits of detection (LODs) at 0.8 μM for CPF and 7.813 nM for TCP. The linear regression concentration ranges were 1.6–12.5 μM for CPF and 15.6–125 nM for TCP, aligning with environmental standard limits and ensuring the biosensor's effectiveness in real-world scenarios. This innovative biosensing approach offers a robust, user-friendly tool for on-site environmental monitoring, significantly mitigating OPs contamination and advancing current detection technologies to meet environmental protection standards.

Multimodal, Ultrasensitive, and Biomimetic Electronic Skin Based on Gradient Micro‐Frustum Ionogel for Imaginary Keyboard and Haptic Cognition

AbstractElectronic skins (E‐skins) are poised to revolutionize human interaction not only with one another but also with machines, electronics, and surrounding environment. However, the wearable E‐skin that simultaneously offers multiple sensing capabilities, high sensitivity, and broad sensing ranges remains a great challenge. Here, drawing inspiration from human haptic perception, a multimodal, ultrasensitive, and biomimetic E‐skin (MES) founded on micro‐frustum ionogel is developed based on iontronic capacitive and triboelectric effects for imaginary keyboard and multifunctional haptic cognition. Leveraging simultaneously the ionogel as capacitive layer and triboelectric layer, the MES enables human‐dermis perception performances of high sensitivity (357.56 kPa−1), low limit of detection (0.47 Pa), and broad linear detection range (0–500 kPa). Moreover, human finger joint movements can be precisely monitored by the attached MES and be transferred into accurate typed letter information on an imaginary keyboard. More importantly, by harnessing signal acquisition/processing circuits and machine learning, the real‐time haptic cognition of different materials, surface roughness, and contact pressure can be achieved by the MES, which endows the advancement of interaction between next‐generation intelligent robot and physical environment. Consequently, the proposed MES demonstrates impressive potentials in the fields of wearable electronics, human–machine interaction (HMI), and Artificial Intelligence (AI).

Innovating uric acid Biosensing: Development of a GSH@Cd-Mediated Dual-Signal fluorometric method

Uric acid (UA) is a crucial biomarker for various metabolic and renal disorders, making its accurate determination essential for clinical diagnostics and disease management. This study presents a novel fluorometric method for UA detection using a glutathione@cadmium/carbon dots/uricase system (GSH@Cd/CDs/uricase system), which offers enhanced sensitivity and selectivity compared to existing techniques. The method employs a cascade reaction mechanism initiated by uricase-catalyzed oxidation of UA to produce H2O2. This H2O2 subsequently oxidizes GSH to oxidized glutathione (GSSG), releasing cadmium ions from GSH complexes. The liberated Cd2+ ions interact with two types of carbon dots (CDs) in the system: blue-emitting CDs (BCDs) and red-emitting CDs (RCDs). This interaction triggers a dual fluorescence response, characterized by a decrease in fluorescence intensity at 400 nm (BCDs) and an increase at 610 nm (RCDs), enabling ratiometric detection of UA levels. Comprehensive characterization and mechanistic investigations were conducted using various optical and morphological techniques, including transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and fluorescence spectroscopy. The method exhibits outstanding analytical performance, characterized by strong linearity (R2 = 0.9932), a broad detection range (0.05–7.0 μM), and a low detection limit of 0.015 μM. The method demonstrated excellent selectivity against common interfering substances and was successfully applied to human serum and urine samples with high recovery values (97.65 % to 99.20 %), highlighting its potential for clinical applications. This innovative approach combines the specificity of enzymatic recognition with the sensitivity of dual-emission fluorescence, offering a promising tool for accurate UA quantification in complex biological matrices.

Highly Stretchable Supercapacitor‐Type Multifunctional Self‐Powered Porous Electronic Skins

AbstractThe development of highly stretchable self‐powered electronic skins with a broad detection range is urgently needed but remains a great challenge. Herein, unprecedented highly stretchable, broad‐range‐response, supercapacitor‐type, one‐body, and self‐powered electronic skins are developed by assembling porous polyurethane/polypyrrole electrode, polyacrylic acid/polyacrylamide ionic gel electrolyte, and porous polyurethane/MXene electrode. The folded porous structure of the electrodes significantly enhances the stretchability, while the modulus‐gradient multilayer structure of the device effectively broadens the pressure detection range. The electronic skins combine self‐powered dynamic/static pressure sensing, ultrabroad detection range (20 Pa–3.5 MPa), ultrahigh stretchability up to 387%, excellent compression stability (5000 cycles under 195 kPa), and good stretching stability (500 cycles under 200% tensile strain). They have the capability of monitoring human body motions, physiological signals, and high pressures from motorcycle tires, as well as tactile sensing of robotic grippers. In addition, they can be applied for highly stretchable thermal management and electromagnetic shielding devices. This work provides a new strategy for the development of highly stretchable, broad‐range‐response, and multifunctional self‐powered wearable electronics and sensors.

In situ constructing p-n heterojunction NiCo-MOF/LDH with built-in electric field for wide response range of glucose sensing

The development of non-precious metal nanomaterial for glucose sensor with sensitive performance and broad detection range will be a great challenge. In this study, a p-n heterojunction catalyst (NiCo-MOF/LDH) is devised as an efficient electrocatalytic oxidation material for glucose detection in alkaline solutions. As an enzyme-free sensor of glucose, (NiCo-MOF/LDH) exhibits good electrochemical properties with high sensitivity of 27.76 μA mM−1 cm−2, a low detection limit of 8 µM at a signal-to-noise ratio of 3 and a wide linear range (40 μM-16 mM). The results indicate that the Mott-Schottky junction between NiCo-MOF and NiCo-LDH constructs the built-in electric field (BEF) and achieves the redistribution of surface charge. The local positive charge induced by the p-n junction allows the NiCo-MOF side to adsorb more OH−, and the local negative charge allows the NiCo-LDH side to adsorb glucose positively charged H, optimizing the adsorption reactants and key intermediates. At the same time, the sensor is successfully applied to the detection of glucose in actual sample samples. Hence, the p-n heterojunction NiCo-MOF/LDH provides a rational strategy for a non-enzymatic glucose sensing catalyst.

Sensitive detection of persulfate by a novel self-powered electrochemical sensor with carbon cloth electrodes modified with tin-doped cobalt tetroxide.

The accurate and rapid detection of persulfate concentration is important for environmental decontamination and human health protection. In this work, a novel self-powered electrochemical sensor for the sensitive monitoring of persulfate was developed, which utilized cobalt tetroxide (Co3O4@CC) or tin-doped cobalt tetroxide (SnxCo3-xO4@CC) cathode as the sensing element and anode with electrogenic microorganisms as the power supplier. The Co3O4@CC and SnxCo3-xO4@CC electrodes were fabricated by in situ growing nanostructured Co3O4 or SnxCo3-xO4 catalysts on carbon cloth. Electrochemical tests revealed that these electrodes exhibited excellent catalytic reduction performance toward persulfate because of the synergistic catalysis by Co3O4 and electrode electrons, well-exposed Co2+/Co3+ catalytic sites, and high electron transfer efficiency. Tin doping could enhance the catalytic persulfate reduction by improving the conductivity and electron transfer of the Co3O4 catalyst. The electrode prepared at a hydrothermal temperature of 90°C and a tin dosage of 0.286g·cm-2 achieved the highest persulfate reduction activity under pH 7. The sensing properties of the self-powered sensors toward persulfate were explored in detail. Results showed that under the optimal external load of 300 Ω, the proposed sensor could display a broad detection range of 0 to 1500μmol L-1 K2S2O8 with sensitivities of 1.13 and 0.12 μA μmol-1 L, a detection limit of 1.11μmol L-1 (S/N = 3), and a fast response time within 30s. The sensors also presented satisfactory reproducibility and selectivity during the detection of persulfate. The proposed sensor will provide a new approach for sensitive, on-site, and real-time monitoring of persulfate for a wide range of applications.

Fabrication of natural enzyme-covered / amino-modified Pd-Pt bimetallic-doped zeolitic imidazolate framework for ultrasensitive detection of metabolites.

The present article introduced an natural enzyme-covered/amino-modified Pd-Pt bimetallic-doped zeolitic imidazolate framework (NAPPZ) for ultrasensitive and specific detection of glucose. The dodecahedral nanomaterial zeolitic imidazolate framework (ZIF-8)-loaded Pd-Pt bimetallic nanoparticles endowed the composite with peroxidase-like activity. The modification with glucose oxidase (GOx) facilitated the rapid access of H2O2 produced through glucose oxidation to the Pd-Pt nanoparticles vicinity reducing diffusion. GOx specifically catalyzes the transformation of glucose into H2O2, which then H2O2 rapidly migrates to the Pd-Pt nanoparticles, catalyzing the oxidation of colorless o-phenylenediamine into the orange-yellow product 2,3-diaminophenazine. Based on the aforementioned cascade reaction, the NAPPZ and NAPPZ based on ChOx were utilized for detecting glucose in human urine samples and cholesterol in milk, respectively. The NAPPZ strategy presented a broad detection range (20-1100μmol L-1) and a low detection limit (15.9μmol L-1) for glucose, and the NAPPZ based on ChOx strategy approach offered a broad detection range (10-500μmol L-1) and low detection limit (6.4μmol L-1) for cholesterol. Therefore, this novel method holds significant potential in the areas of clinical diagnostics and food safety.

Rapid and selective quantitative colourimetric analysis of nitrite in water using a S-Nitrosothiol based method

This study introduces a novel S-nitrosothiol based method for the rapid and highly selective detection of nitrite in complex water matrices. Sodium 3-mercapto-1-propanesulfonate forms a distinctive pink S-nitrosothiol compound upon interaction with nitrite in acidic media, allowing both visual and quantitative detection. Various factors affecting the absorbance of the final product were investigated, including pH, reaction time, acid type, and sodium 3-mercapto-1-propanesulfonate concentration. UV–Vis spectrophotometric analysis demonstrated an excellent linear correlation (R2 = 0.99) across a broad detection range (0.05 to 80 mmol l-1), while showing no interference from common ions such as nitrate or dissolved organic matter, a limitation frequently observed in conventional UV-based nitrite detection methods. The assay was further adapted into a pellet form to simplify field use, operating effectively at room temperature with a low detection limit (1.4 ppm). The S-nitrosothiol based method represents a safer and more environmentally friendly option for nitrite detection and shows a promising potential as a valuable addition to both field and laboratory water testing kits for nitrite analysis.

Carbon quantum dots composite for enhanced selective detection of dopamine with organic electrochemical transistors

A compact organic electrochemical transistors (OECT) sensor enriched with carbon quantum dots (CQDs) was developed to enhance the transconductance of an electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) film, enabling the precise and selective detection of dopamine (DA). Accurate monitoring of DA levels is critical for diagnosing and managing related conditions. Incorporating CQDs, we have achieved a remarkable up to threefold increase in current at the DA detection peak in differential pulse voltammetry. This enhancement showcases superior selectivity even in the presence of high concentrations of interferents like uric acid and ascorbic acid. This material significantly boosts the sensitivity of OECTs for DA detection, delivering an amperometric response with a detection limit of 55 nM and a broader detection range (1 − 500 µM). Our results underscore the potential of low-dimensional carbonaceous materials in creating cost-effective, high-sensitivity devices for detecting DA and other biomolecules. This breakthrough sets the stage for the development of next-generation biosensors for point-of-care diagnostics.Graphical