Detection Of Organic Compounds Research Articles

Low Power Gas Sensors: From Structure to Application.

Gas sensors are pivotal across industries, encompassing environmental monitoring, industrial safety, and healthcare. Recently, a surge in demand for low power gas sensors has emerged, driven by the huge need for applications in portable devices, wireless sensor networks, and the Internet of things (IoT). The practical realization of a densely interconnected sensor network demands gas sensors to have low power consumption for energy-efficient operation. This Perspective offers a comprehensive overview of the progress of low-power sensors for gas and volatile organic compound detection, with a keen focus on the interplay between sensing materials (including metal oxide semiconductors, metal-organic frameworks, and two-dimensional materials), sensor structures, and power consumption. The main gas sensing mechanisms are discussed, and we delve into the mechanisms for achieving low power consumption including material properties and sensor design. Furthermore, typical applications of low power gas sensors are also presented, including wearable technology, food safety, and environmental monitoring. The review will end by discussing some open questions and ongoing needs.

Advances in volatile organic compounds detection: From fundamental research to real-world applications

Volatile organic compounds (VOCs) play a crucial role in affecting health, environmental integrity, and industrial operations, from air quality to medical diagnostics. The need for highly sensitive and selective detection of these compounds has spurred innovation in sensor technologies. This editorial introduces a special collection of articles in Applied Physics Reviews, exploring the latest advancements in VOC detection technologies. The featured works cover a range of innovations, including electrostatically formed nanowires, chiral liquid crystals, and graphene-based sensors enhanced by machine learning. Together, these articles highlight the dynamic progress in VOC detection, striving for improved sensitivity, selectivity, and real-world applicability. This special collection not only showcases pioneering research but also provides valuable insights into future trends and potential applications in the field.

Nanobioprospecting of photoautotrophs for the fabrication of quantum dots: mechanism and applications.

Quantum dots (QDs), also known as nanoparticle-based fluorescent probes, are luminescent semiconductor particles with a size range of 2-20nm. The unique optical and electronic capabilities of QDs have led to expanded applications in several fields such as optoelectronics, transistors, sensors, photodetection, catalysis, and medicine. The distinct quantum effects of nanocrystals can be controlled by changing their sizes and shapes using a variety of top-down and bottom-up tactics. QDs were traditionally fabricated using complex, expensive, toxic, and aggressive chemical techniques, which limited their application in a variety of disciplines. A unique approach for the biosynthesis of nanomaterials has been devised, which employs living organisms in the synthesis process and adheres to green chemistry principles. Biogenic QDs have favorable physicochemical features, biocompatibility, and fewer cytotoxic effects as a result of using natural biomolecules and enzymatic processes for mineralization, detoxification, and nucleation of metals and nonmetals to synthesize QDs. This is the first comprehensive review of its kind that highlights the synthesis of several doped and undoped QDs, including graphene QDs, carbon dots, silicon QDs, N/S-CDs, silver-CDs, cadmium-selenium QDs, and zinc oxide QDs, exclusively using photoautotrophic algae and plants. The different plausible mechanisms behind phyco- and phyto-fabrication of QDs are also discussed in detail along with their applications that include detection of organic and inorganic compounds, degradation of hazardous dyes, free radical scavenging, antimicrobial activity, cytotoxicity and bioimaging. Thus, this review aims to give valuable insights for the rational fabrication of photoluminescent nanomaterials with tunable structural and functional properties.

Recent Advancements in MXene-Based Biosensors for Health and Environmental Applications-A Review.

Owing to their unique physicochemical properties, MXenes have emerged as promising materials for biosensing applications. This review paper comprehensively explores the recent advancements in MXene-based biosensors for health and environmental applications. This review begins with an introduction to MXenes and biosensors, outlining various types of biosensors including electrochemical, enzymatic, optical, and fluorescent-based systems. The synthesis methods and characteristics of MXenes are thoroughly discussed, highlighting the importance of these processes in tailoring MXenes for specific biosensing applications. Particular attention is given to the development of electrochemical MXene-based biosensors, which have shown remarkable sensitivity and selectivity in detecting various analytes. This review then delves into enzymatic MXene-based biosensors, exploring how the integration of MXenes with enzymes enhances sensor performance and expands the range of detectable biomarkers. Optical biosensors based on MXenes are examined, focusing on their mechanisms and applications in both healthcare and environmental monitoring. The potential of fluorescent-based MXene biosensors is also investigated, showcasing their utility in imaging and sensing applications. In addition, MXene-based potential wearable biosensors have been discussed along with the role of MXenes in volatile organic compound (VOC) detection for environmental applications. Finally, this paper concludes with a critical analysis of the current state of MXene-based biosensors and provides insights into future perspectives and challenges in this rapidly evolving field.

High-performance virtual sensors array based on a single-chip FBAR for volatile organic compounds (VOCs) detection and classification

The detection and classification of volatile organic compounds (VOCs) are of great significance in atmospheric environment monitoring and have garnered extensive attention in recent decades. This study proposes a virtual sensor array (VSA) for VOC detection and classification fabricating a single-chip high-Q-factor film bulk acoustic resonator (FBAR) functionalized with MIL-101(Cr) thin film, known for its porous crystal structure and high specific surface area. The sensing performance of five different VOCs was evaluated to characterize the VOCs, achieving high detection accuracy calibrated with the Langmuir adsorption model. The FBAR’s frequency response was utilized to determine the sensitivity and limit of detection (LOD), yielding sensitivity and LOD of 85.45 Hz/ppm and 51 ppm, respectively, for isopropanol. The identification and classification capabilities of the proposed VSA for VOCs and their mixtures were assessed using statistical methods and machine learning algorithms, realizing classification accuracies of 100 % for pure VOCs and 94.6 % for mixtures. The developed VSA demonstrates superior performances in VOC detection and classification, with potential applications across various domains.

Volatile organic compound detection of Buruli ulcer disease: Headspace analysis of Mycobacterium ulcerans and used gauzes of Buruli-compatible ulcers.

Diagnosing Buruli ulcer (BU) is complicated by limited access to the sensitive IS2404 qPCR. Experienced clinicians report a distinct odour of Buruli ulcers. We explored the potential of headspace analysis by thermal desorption-gas chromatography-mass spectrometry to detect volatile organic compounds (VOCs) from Mycobacterium ulcerans both in vitro and clinically. This study was conducted in two phases: a discovery and validation phase. During the discovery phase, VOCs that enable identification of M. ulcerans cultures were determined. During the validation phase, these VOCs were evaluated in clinical samples for which we used gauzes from patients with skin ulcerations in the Democratic Republic of Congo. Seven M. ulcerans headspace samples were compared with four from sterile growth medium and laboratory environmental air. The univariate analysis resulted in the selection of 24 retained VOC fragments and a perfect differentiation between cultures and controls. Sixteen of 24 fragments were identified, resulting in eleven unique compounds, mainly alkanes. Methylcyclohexane was the best performing compound. Based on these 24 fragments, headspace samples originating from gauzes of 50 open skin lesions (12 qPCR positive and 38 negative) were analysed and an AUC of 0.740 (95%-CI 0.583-0.897) was obtained. As this is an experimental study, future research has to confirm whether the identified compounds can serve as novel biomarkers.

Metal-organic framework modified open-cavity optical fiber Fabry-Pérot interferometer for volatile organic compound detection

Detection of volatile organic compounds (VOCs) is crucial in industrial production, environmental monitoring, and public safety. VOCs sensors need to be intrinsically safe, given the flammability and toxicity of common VOCs. Fiber optic sensors offer a passive and flexible solution for VOCs detection, attracting significant attention from researchers. In this study, ZIF-8, a subset of metal-organic frameworks, is applied to a side-polished silicon wafer, forming an open-cavity optical fiber Fabry-Pérot interferometer (FPI) with a fiber patch cable and a 3D-printed structural part. The sensing performance for prevalent VOCs, including methylbenzene, methanol, and ethanol, is experimentally explored, exhibiting sensitivities of 0.118 p.m./ppm, 0.177 p.m./ppm, and 0.412 p.m./ppm, respectively. Sensitivity differences are analyzed and demonstrated at the molecular level. The proposed technologies offer advantages such as easy fabrication, intrinsic safety, small size, and good selectivity, providing an alternative for VOCs detection in industrial production.

The volatile organic compounds detection in MDR Gram-negatives antimicrobial susceptibility testing: Results from a four-month laboratory experience

Systemic bacterial infections represent a significant clinical challenge due to the increasing resistance rate towards antimicrobials. An essential key to controlling antimicrobial resistance spread is to administer targeted therapy after a precise minimum inhibitory concentration reporting. Among the available fast technologies for antimicrobial susceptibility testing (AST), the VITEKⓇ REVEAL™ (Biomerieux, Florence, Italy) proposes volatile organic compounds (VOC) colourimetric arrays to discriminate between susceptible and resistant Gram-negative isolates directly from positive blood cultures. We evaluated this methodology during a four-month laboratory experience on 40 positive blood culture samples, reporting a comparison to standard culture-based methods. The protocol revealed an essential agreement of 100 % between the conventional and the experimental procedures, while the categorical agreement resulted in 97.5 % due to one very major error (VME) for meropenem/vaborbactam in K. pneumoniae. Although further studies will be necessary to investigate its performance on rare microorganisms, the VITEKⓇ REVEAL™ demonstrated an optimal sensitivity in defining MIC values for multi-drug resistant (MDR) microorganisms. These results encourage the application of the method in all high-risk epidemiological areas, confirming the effectiveness of VOC detection in monitoring bacterial susceptibility profiles.

Integrated Mixed Potential Gas Sensor with Efficient Structure for Discriminative Volatile Organic Compounds Detection.

Amid growing interest in the precise detection of volatile organic compounds (VOCs) in industrial field, the demand for highly effective gas sensors is at an all-time high. However, traditional sensors with their classic single-output signal, bulky and complex integrated structure when forming array often involve complicated technology and high cost, limiting their widespread adoption. Here, this study introduces a novel approach, employing an integrated YSZ-based (YSZ: yttria-stabilized zirconia) mixed potential sensor equipped with a triple-sensing electrode array, to efficiently detect and differentiate six types of VOCs gases. This innovative sensor integrates NiSb2O6, CuSb2O6, and MgSb2O6 sensing electrodes (SEs), which are sensitive to pentane, isoprene, n-propanol, acetone, acetic acid, and formaldehyde gases. Through feature engineering based on intuitive spike-based response values, it accentuates the distinct characteristics of every gas. Eventually, an average classification accuracy of 98.8% and an overall R-squared error (R2) of 99.3% for concentration regression toward six target gases can be achieved, showcasing the potential to quantitatively distinguish between industrial hazardous VOCs gases.

Exploring Novel Approaches: Surface Functionalization of Metal Organic Semiconductor as Sensing Material for Volatile Organic Compounds Detection

Detecting volatile organic compounds (VOCs) is imperative in healthcare, industrial safety, and environmental monitoring due to their potential harm to human health and the environment. Addressing the challenges in VOC detection, research has focused on creating sensors with rapid response and high selectivity, notably through surface functionalization of metal organic semiconductors. Metal organic semiconductors offer advantages over standard metal oxide semiconductors (MOS), demonstrating superior sensitivity and selectivity even at low temperatures and concentrations. Notably, conductive particle-polymer hybrids and conjugated polymers as metal organic semiconductors show promise for VOCs detection. This review comprehensively explores surface functionalization in metal organic semiconductors, covering principles, mechanisms governing gas sensing behavior and the pivotal role of surface functionalization in enhancing selectivity and performance. Additionally, various surface functionalization options, such as nanoparticles, nanostructures, and organic ligands, are discussed.

Hybrid Nanoarchitectronics of Tantalum Oxide‐Coated Gold Nanoparticles as Localized Surface Plasmon Resonance‐Based Sensors for Volatile Organic Compounds Detection

Hybrid Nanoarchitectronics of Tantalum Oxide‐Coated Gold Nanoparticles as Localized Surface Plasmon Resonance‐Based Sensors for Volatile Organic Compounds Detection

Environmental analogs from yellowstone hot springs on geochemical and microbial diversity with implications for the search for life on Mars

From Viking landers to Perseverance rover, Mars has been explored by several in situ missions capable of analyzing organic compounds. Results from the SAM and SHERLOC on Curiosity and Perseverance, respectively, support the detection of lean organic matter (at ppb-ppm levels) in the top surface samples, although the source(s) and preservation mechanisms are still ambiguous. Perseverance is currently exploring a fluvio-lacustrine system at Jezero crater and may explore an ancient volcanic terrain after exiting the crater. As Perseverance would collect samples for potential return to Earth, preparation is needed for sample return efforts through various means including i) the detection of trace organic compounds in various matrices, ii) validation of compounds identified by Martian rovers, and iii) better understanding of mechanisms of their production on Mars. On these returned samples, the community may be able to resolve the timing of organic matter formation and refine hypotheses regarding organic preservation in Martian soils despite the presence of numerous oxidants, salts, and pH-temperature intra and inter-site variations that are less conductive to long-term preservation of organic matter. For instance, acidic conditions promote clay catalyzed isomerization, but seem to benefit for the fatty acid preservation producing organic-salts or favoring salt dissolution in the matrix to protect organic compounds from radiations and water alteration. With a similar aim, we selected samples from Yellowstone National Park hot springs and silica sinters as analogs to locations visited by Curiosity and Perseverance or – in the future – Rosalind Franklin rover. The hot springs in this study developed over hundreds to thousands of years, providing optimal conditions (i.e., matrix composition, temperature, pH) of preservation for organic molecules, extremophilic and mesophilic cells. In our study, the most well preserved organic matter and biosignatures were detected in acidic silica sinters with a surface (water) temperature below 50 °C and a minor crystalline phase. The gas chromatography – mass spectrometry molecular analysis revealed a variety of organic compounds we classified as bioindicators (such as amino acids, nucleobases, and sugars), and biosignatures (such as long-chain branched and/or (poly)unsaturated lipids, secondary metabolites involved in the quorum sensing or communication between individuals). We validated with a SAM/MOMA-like benchtop extracting oven the organic matter extraction protocols performed with the SAM experiment. We identified using the different SAM and MOMA extraction protocols (pyrolysis and wet-chemistry derivatizations) eight microbial classes through a unique untargeted environmental metabolomics’ method embracing space flight technology constraints. Additionally, we identified one (and likely two) agnostic biosignature(s): i) the concomitance of some elements and organic compounds in the analogs (correlation of organic matter elements: C, N, S, P and organic molecules co-located with essential biological elements: Fe, Mg, V, Mn and non-essential biological elements concentrated by microorganisms: As, Cs, Ga), and ii) the negative isotope C and N ratio demonstrating organic molecules rich in 12C and 14N: archaeal, bacterial, and eukaryotic lipids for an efficient low energy-consuming metabolism.

A Diagnostic Case Study for Manufacturing Gas-Phase Chemical Sensors

In this work, we describe the design, manufacturing development, and refinement of a chemical detection platform designed to identify specific odorants in the natural gas industry. As the demand for reliable and sensitive volatile organic compound (VOC) detection systems is growing, our project aimed to construct multiple prototypes to enhance our detection capabilities and provide portable detection platforms. Throughout the development process across nominally identical and duplicated instruments, various failure modes were encountered, which provided insight into the design and manufacturing challenges present when designing such platforms. We conducted a post hoc root cause analysis for each failure mode, leading to a series of design modifications and solutions. This paper details these design and manufacturing challenges, the analytical methods used to diagnose and address them, and the resulting improvements in system performance. In the end, a debugging flow chart is presented to aid future researchers in solving the possible issues that could be encountered. Our findings show the complexities of bespoke chemical sensor design for unique applications and highlight the critical importance of iterative testing and problem-solving in the development of industrial detection technologies. Achieving consistency across devices is essential for optimizing device-to-device efficiency. The work presented is the first step towards ensuring uniform performance across a production run of chemically sensitive devices. In the future, a universal device calibration model will be implemented, eliminating the need to collect data from each individual device.

Interactions of coinage metal nanoclusters with low-molecular-weight biocompounds.

Nowadays, coinage metal nanoclusters (NCs) are largely presented in diagnostics, bioimaging, and biocatalysis due to their high biocompatibility, chemical stability, and sensitivity to surrounding biomolecules. Silver and gold NCs are usually characterized by intense luminescence and photostability, which is in great demand in the detection of organic compounds, ions, pH, temperature, etc. The experimental synthesis of metal NCs often occurs on biopolymer templates, mostly DNA and proteins. However, this review mainly focuses on the interactions with small biomolecules (SBMs) of a molecular weight less than 1000 Da: amino acids, nucleobases, thiolates, oligopeptides, etc. Such molecules can serve as the templates for an eco-friendly facile one-pot synthesis of biocompatible luminescent NCs. The latter aspect makes NCs suitable for diagnostics and intracellular bioimaging. Another important aspect is the interaction of clusters with biomarkers, which is largely exploited by nanosensors: biomarker detection often occurs through either fluorescence emission "turn-on" or "turn-off" mechanisms. Moreover, as theoretical studies show, electronic absorption spectra and Raman spectra of the metal-organic complexes allow efficient detection of various analytes. In this regard, both theoretical and experimental studies of SBM complexes with metal NCs are in great demand. Therefore, this review aims to summarize up-to-date studies on the interaction of small biomolecules with coinage metal NCs from both theoretical and experimental viewpoints.

Room temperature detection of n-butanol Ce-doped MOF:ZnO sensor under UV activation

Being one of toxic and flammable volatile organic compounds (VOC), n-butanol has brought about many potential health risks, there is an urgent demand for highly sensitive detection techniques to monitor its concentration in occupational environments and the air. In this paper, Ce-doped MOF:ZnO sensors under UV activation for room-temperature detection of n-butanol were synthesized by the co-precipitation method and systemically characterized by XRD, SEM, HRTEM, and XPS. The sensitive performances were evaluated by the use of a WS-30A gas sensor measurement system. The results showed that Ce doping has significantly enhanced the sensitivity of the MOF:ZnO sensors, and the response value of the 0.08 % Ce-doped ZnO sensor has achieved to 397.30, which was 9.32 times higher than that of the pristine MOF:ZnO. And the response and recovery times were 17 and 117 s respectively, demonstrating a speedy detection capability. In addition, the sensor gained excellent stability and reproducibility with special selectivity for n-butanol. The comprehensive achievements of this research would be promising to promote the development of volatile organic compound detection technology and beneficial to the well application in the fields of environmental monitoring, industrial safety, and public health.

Unveiling Colorectal Cancer Biomarkers: Harnessing Biosensor Technology for Volatile Organic Compound Detection.

Conventional screening options for colorectal cancer (CRC) detection are mainly direct visualization and invasive methods including colonoscopy and flexible sigmoidoscopy, which must be performed in a clinical setting and may be linked to adverse effects for some patients. Non-invasive CRC diagnostic tests such as computed tomography colonography and stool tests are either too costly or less reliable than invasive ones. On the other hand, volatile organic compounds (VOCs) are potentially ideal non-invasive biomarkers for CRC detection and monitoring. The present review is a comprehensive presentation of the current state-of-the-art VOC-based CRC diagnostics, with a specific focus on recent advancements in biosensor design and application. Among them, breath-based chromatography pattern analysis and sampling techniques are overviewed, along with nanoparticle-based optical and electrochemical biosensor approaches. Limitations of the currently available technologies are also discussed with an outlook for improvement in combination with big data analytics and advanced instrumentation, as well as expanding the scope and specificity of CRC-related volatile biomarkers.

A stepwise surface ionization method for ion mobility spectrometry.

The detection of organic nitrogen compounds in exhaled breath is expected to provide an early warning of diseases such as kidney disease. Detecting these trace disease markers in exhaled breath with complex composition and high moisture content is a challenge. Surface ionization (SI) shows a highly selective ionization of organic nitrogen compounds, and it is a good candidate for breath analysis combined with ion mobility spectrometry (IMS). A stepwise SI method of low-temperature adsorption/high-temperature ionization was proposed, and trimethylamine (TMA) was detected when combined with an ion mobility spectrometer. TMA at different concentrations and humidity levels and spiked in human breath was detected to evaluate the method's properties. TMA with concentrations from 2 to 200 ppb was detected. The peak intensity of the TMA characteristic ions was linearly related to the "e" exponent of the concentration with a curve fit of 0.996. A standard deviation of less than 0.306% was obtained with 10 replicate analyses of 10ppb TMA. The signal intensity difference between dry and wet (relative humidity > 93%) TMA samples is only 2.7%, and the recovery rate of the sample was 106.819%. SI-IMS based on the stepwise SI method has the advantages of low ionization temperature, high detection sensitivity, strong resistance to humidity interference, and good repeatability. It is a promising method for detecting organic nitrogen compounds in exhaled breath.

Lignin-based Carbon NanomaterialsforBiochemical Sensing Applications.

Lignin-based carbon nanomaterials offer several advantages, including biodegradability, biocompatibility, high specific surface area, ease of functionalization, low toxicity, and cost-effectiveness. These materials show promise in biochemical sensing applications, particularly in the detection of metal ions, organic compounds, and human biosignals. Various methods can be employed to synthesize carbon nanomaterials with different dimensions ranging from 0D to 3D, resulting in diverse structures and physicochemical properties. This study provides an overview of the preparation techniques and characteristics of multidimensional (0-3D) lignin-based carbon nanomaterials, such as carbon dots (CDs), carbon nanotubes (CNTs), graphene, and carbon aerogels (CAs). Additionally, the sensing capabilities of these materials are compared and summarized, followed by a discussion on the potential challenges and future prospects in sensor development.

Facile Preparation of TiO2NTs/Au@MOF Nanocomposites for High-Sensitivity SERS Sensing of Gaseous VOC.

Surface-enhanced Raman spectroscopy (SERS) is a promising and highly sensitive molecular fingerprint detection technology. However, the development of SERS nanocomposites that are label-free, highly sensitive, selective, stable, and reusable for gaseous volatile organic compounds (VOCs) detection remains a challenge. Here, we report a novel TiO2NTs/AuNPs@ZIF-8 nanocomposite for the ultrasensitive SERS detection of VOCs. The three-dimensional TiO2 nanotube structure with a large specific surface area provides abundant sites for the loading of Au NPs, which possess excellent local surface plasmon resonance (LSPR) effects, further leading to the formation of a large number of SERS active hotspots. The externally wrapped porous MOF structure adsorbs more gaseous VOC molecules onto the noble metal surface. Under the synergistic mechanism of physical and chemical enhancement, a better SERS enhancement effect can be achieved. By optimizing experimental conditions, the SERS detection limit for acetophenone, a common exhaled VOC, is as low as 10-11 M. And the relative standard deviation of SERS signal intensity from different points on the same nanocomposite surface is 4.7%. The acetophenone gas achieves a 1 min response and the signal reaches stability in 4 min. Under UV irradiation, the surface-adsorbed acetophenone can be completely degraded within 40 min. The experimental results demonstrate that this nanocomposite has good detection sensitivity, repeatability, selectivity, response speed, and reusability, making it a promising sensor for gaseous VOCs.

Synthesis of ZnO@Fe2O3 microflowers with enhanced performance in volatile organic compound detection

Metal-oxide semiconductor is widely applied in gas sensor for volatile organic compound detection. However, these sensors usually exhibit poor selectivity and inferior sensitivity. Here, ZnO@Fe2O3 microflowers were synthesized using FeOOH microflowers as precursors via a simple solution reaction route, followed by heat treatment. The ZnO@Fe2O3 microflowers were characterized using a series of techniques, and their sensing responses to volatile organic compounds (VOCs) were evaluated in comparison with those of pristine Fe2O3. The ZnO@Fe2O3 microflower sensor exhibited better responses to several gases, especially acetone, with a response of 74.3 towards 100 ppm acetone, which is 2.85 times higher than that of the Fe2O3 microflower sensor. The sensor also presented high selectivity, reproducibility, and stability in sensing different VOCs. The large specific surface area, heterostructure, favorable hierarchical flower-like nanostructure assembled by the nanosheets, and high porosity of the ZnO@Fe2O3 microflowers contributed to its enhanced gas-sensing responses. Overall, this synthetic strategy for fabricating flower-like ZnO@Fe2O3 nanostructures can be widely applied.