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Application of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging for Evaluating the Quality of Fish Fillets
摘要： Consumption of fish is rapidly increasing worldwide. It is important to evaluate fish fillet quality because fish undergoes physical and chemical changes during frozen storage. Fish fillets exhibit formaldehyde (FA) accumulation from the decomposition of trimethylamine N-oxide. FA is a powerful protein denaturant; thus, it is important to avoid FA buildup during fish processing to preserve fish quality, especially texture. To determine where FA accumulates, in order to maintain the quality of fish fillets, we performed matrix-assisted laser desorption/ionization mass spectrometry imaging, aiming to identify muscle-derived peptides, which reflect conditions such as denaturation and/or aggregation. We used frozen sections from which lipophilic molecules were washed out and detected various peptide peaks. Furthermore, we tried to identify indices to represent fish fillet softening by protease treatment. We could detect characteristic peaks owing to FA and protease treatment; the findings were consistent with the results of texture profiles showing fish fillet’s real solidity. These molecules might thus serve as effective markers to evaluate fish fillet quality.
关键词： mass spectrometry imaging,peptide,matrix-assisted laser desorption/ionization,protease,formaldehyde
更新于2025-09-23 15:19:57
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Fabrication of Ag3PO4/TiO2 Composite and Its Photodegradation of Formaldehyde Under Solar Radiation
摘要： In order to improve the photocatalytic degradation performance of Ag3PO4 and reduce the cost of photocatalyst made of Ag3PO4, a kind of Ag3PO4/TiO2 composite was successfully fabricated via a simply precipitation method for the Ag3PO4 nanoparticles being loaded on the surface of commercial titanium dioxide (P25) to form a heterostructure. The Ag3PO4/TiO2 composite were characterized by FT-IR, XRD, XPS, FE-SEM, HR-TEM, DRS and PL and applied for the degradation of formaldehyde solution under solar radiation. The results showed that the degradation rat of Ag3PO4/TiO2 composite (0.01796 min?1) was much higher than that of pure Ag3PO4 (0.00775 min?1), indicating that the Ag3PO4/TiO2 composite possessed better photocatalytic degradation activity for the formaldehyde solution than pure Ag3PO4. The composite significantly decreased the dosage of silver for photocatalyst under solar radiation, thereby reduced the cost of the photocatalyst made from silver.
关键词： Ag3PO4,Ag3PO4/TiO2 composite,Photocatalytic formaldehyde
更新于2025-09-19 17:15:36
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High performance nBn detectors based on InGaAsSb bulk materials for short wavelength infrared detection
摘要： Objective: To investigate whether hydrogen sulfide (H2S) counteracts formaldehyde (FA)-induced cognitive defects and whether the underlying mechanism is involved in the upregulation of hippocampal brain-derived neurotrophic factor (BDNF) expression. Methods: The cognitive function of rats was evaluated by the Morris water maze (MWM) test and the novel object recognition test. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). The neuronal apoptosis in the hippocampal CA1 region was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end (TUNEL) staining. The expression of the BDNF protein was detected by Western blot and immunohistochemistry. Results: We found that sodium hydrosulfide (NaHS, a donor of H2S) significantly reversed the impairment in the function of learning and memory in the MWM test and the novel objective recognition task induced by intracerebroventricular injection of FA. We also showed that NaHS significantly reduced the level of MDA, elevated the level of SOD, and decreased the amount of TUNEL-positive neurons in the hippocampus of FA-exposed rats. Moreover, NaHS markedly increased the expression of hippocampal BDNF in FA-exposed rats. Conclusions: H2S attenuates FA-induced dysfunction of cognition and the underlying mechanism is involved in the reduction of hippocampal oxidative damage and apoptosis as well as upregulation of hippocampal BDNF.
关键词： Cognitive defect,Oxidative stress,Brain-derived neurotrophic factor,Formaldehyde,Hydrogen sulfide,Apoptosis
更新于2025-09-19 17:13:59
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Ppb-level formaldehyde detection system based on a 3.6???μm interband cascade laser and mode-locked cavity enhanced absorption spectroscopy with self-calibration of the locking frequency
摘要： A mid-infrared formaldehyde (H2CO) detection system was demonstrated using a continuous-wave distributed-feedback interband cascade laser (DFB-ICL) emitting at 3.6 μm as light source and an assembly F-P cavity with 20 m effective optical path length as gas chamber. The laser and the cavity were locked to the H2CO absorption peak simultaneously by an electro-optic modulation based automatic Pound-Drever-Hall (PDH) scheme which consist of two steps: dynamic PDH locking and continuous PDH locking. Before continuous PDH locking, the dynamic PDH locking was conducted to acquire the H2CO absorption spectrum and calibration the locking frequency. Then, the cavity transmitted intensity was detected continuously to characterize the gas concentration. H2CO measurements were conducted to evaluate the performance of the sensor system. A linear relationship was observed between the voltage of the absorption signal and the H2CO concentration within the range of 0–6 ppm. Based on Allan deviation analysis, a minimum detection limit of 5.8 ppb was achieved with an averaging time of 30 s.
关键词： Cavity enhanced absorption spectroscopy,Mid-infrared,Interband cascade laser,Formaldehyde detection
更新于2025-09-19 17:13:59
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In situ generated plasmonic silver nanoparticles sensitized amorphous titanium dioxide for ultrasensitive photoelectrochemical sensing of formaldehyde
摘要： Trace concentration of formaldehyde can damage human health and environment. Consequently, it is of great significance to develop an ultrasensitive sensor for its determination. Herein, an ingenious and efficient photoelectrochemical sensor for formaldehyde was constructed by amorphous TiO2 hollow spheres incorporated with Ag+ ions, which were brought about by silica templates etching and then the exchange of Ag+/Na+ ions. The amorphous TiO2 acted as the dual role of Ag+ ion probe carriers and photoelectric materials. Upon exposure to the increased concentration of formaldehyde, the Ag nanoparticles were produced in situ and photocurrent amplification was then achieved in a proportional manner. It is attributed to the injection of hot electrons from plasmonic Ag nanoparticles into the conduction band of amorphous titanium dioxide and enhanced the photocurrent therefore. The linear relationship between 1 and 400 pmol L-1 was resulted from the enhanced photocurrent and the increased concentration of formaldehyde, and the detection limit was 0.4 pmol L-1. Benefited from an in situ and unique sensitization strategy, this PEC sensor exhibited many advantages such as sensitivity, selectivity, cost-effectiveness, convenience of fabrication, low power consumption, and stability.
关键词： Plasmon,Formaldehyde,Silver nanoparticles,Sensing,Photoelectrochemical
更新于2025-09-16 10:30:52
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Quantitative measurements of formaldehyde in the low-temperature oxidation of iso-octane using mid-infrared absorption spectroscopy
摘要： Time-resolved quantitative measurements of formaldehyde (HCHO) in the low-temperature oxidation of iso-octane using a rapid compression machine have been performed with mid-infrared laser absorption spectroscopy. Due to the weak interference of the broadband absorption of iso-octane, a two-color detection scheme was applied to HCHO detection. The cross-sections of HCHO and iso-octane in two colors were measured using the rapid compression machine in the temperature range of 450–737 K and pressure range of 100–700 kPa. The time-resolved quantitative HCHO profiles in the low-temperature oxidation of iso-octane at 0.77 MPa, 645 K, and an equivalence ratio of 1.0 were successfully obtained. The calculated HCHO profiles using the latest chemical kinetic model of iso-octane show the same tendency as the experimental profiles.
关键词： formaldehyde,mid-infrared absorption spectroscopy,iso-octane,low-temperature oxidation,rapid compression machine
更新于2025-09-16 10:30:52
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Improved formaldehyde gas sensing properties of well-controlled Au nanoparticle-decorated In2O3 nanofibers integrated on low power MEMS platform
摘要： Approaches for the fabrication of a low power-operable formaldehyde (HCHO) gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide (In2O3) nanofibers decorated with well-dispersed Au nanoparticles as a sensing material. Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process. Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers. The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes. The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system (MEMS) technique. The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity. The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration, the size of the adsorbed Au nanoparticles, the applied power to raise the temperature of a sensing part and the kind of target gases.
关键词： Formaldehyde,Gold nanoparticle,In2O3 nanofiber,Gas sensor,Micro-platform,Low power
更新于2025-09-12 10:27:22
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Development of a novel wavelength selection method for the trace determination of chlorpyrifos on Au@Ag NPs substrate coupled surface-enhanced Raman spectroscopy
摘要： In this study, ethylene glycol modified urea formaldehyde resin (EUF) was synthesized from urea, paraformaldehyde and ethylene glycol, and then incorporated into rigid polyurethane foams (RPUFs) as a reactive-type liquid flame retardant. The structure of EUF was characterized by Fourier transform infrared spectroscopy, and the thermal degradation properties and fire behaviors of RPUFs were characterized by limiting oxygen index (LOI), cone calorimetry test and thermogravimetry analysis. The results show that the incorporation of EUF results in an increase in the thermal stability and LOI of RPUFs. As the EUF loading increases, the peak heat release rate, total smoke release and CO/CO2 weight ratio of RPUFs decrease significantly. This is because EUF can release non-flammable gases during the initial degradation of polyurethane foams and promote the formation of the compact char layer, which can serve as an effective shield against heat, oxygen and combustible volatiles during the combustion. However, EUF shows negative effect on the cell morphology and mechanical properties of RPUFs. In conclusion, EUF has excellent performance in flame retardancy and smoke suppression for RPUFs.
关键词： Rigid polyurethane foam,Fire behavior,Flame retardant,Urea formaldehyde resin
更新于2025-09-11 14:15:04
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Constructing hierarchical SnO2 nanofiber/nanosheets for efficient formaldehyde detection
摘要： SnO2 nanofiber/nanosheets with hierarchical nanostructures were successfully synthesized via a facile hydrothermal method by using hollow SnO2 nanofibers as the backbone. The microstructure, morphology, chemical composition, oxidation states and surface areas of SnO2 nanofibers, SnO2 nanofiber/nanosheets and SnO2 nanosheets were comparatively studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The characterization results indicated that the hierarchical SnO2 nanofiber/nanosheets were constructed by nanosheets arrays uniform growth on the surface of nanofibers. Sensing performances of SnO2-based nanomaterials were investigated utilizing formaldehyde (HCHO) as a target gas. Compared to SnO2 nanofibers, nanosheets and the physical mixture of nanofibers and nanosheets, the gas sensor based on SnO2 nanofiber/nanosheets exhibited better response, more excellent selectivity, transient response and trace detection ability to HCHO gas. The response (Ra/Rg) of the gas sensor is 57 toward 100 ppm HCHO at 120 °C, which is about 300% and 200% higher than that of pure SnO2 nanofibers sensors and SnO2 nanosheets sensors, respectively. Furthermore, the sensor has an excellent response/recovery performance with 4.7 s and 11.6 s for detecting 100 ppm HCHO. Both the growth process and the gas sensing mechanism of SnO2 hierarchical nanostructures were discussed. Successful preparation of SnO2 nanofiber/nanosheets is attributed to uniform decoration of seeds on the nanofibers and suitable growth conditions of nanosheets. Enhanced sensing performance mainly result from the synergistic effect of nanofibers and nanosheets, hierarchical structures and larger specific surface areas. The synthetic strategy can also be applied in preparing hierarchical materials of different constituent materials.
关键词： Homogeneous materials,SnO2 nanofiber/nanosheets,Formaldehyde gas sensors,Hierarchical structure
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) 6TH INTERNATIONAL CONFERENCE ON PRODUCTION, ENERGY AND RELIABILITY 2018: World Engineering Science & Technology Congress (ESTCON) - Kuala Lumpur, Malaysia (13–14 August 2018)] - Development of nanocomposites on the basis of graphene nanoplatelets
摘要： The prospects for using a phenol-formaldehyde resin (PFR) as a reactive surfactant in the preparation of highly concentrated dispersions of carbon nanostructured materials (up to 1 %) are considered in the present paper. Modifying graphene nanoplatelets (GNPs) with this surfactant promotes the effect of targeted self-assembly of carbon nanoparticles in solution (with decreasing pH), which makes it possible to obtain nanocomposites with improved properties. It is important that the use of highly concentrated dispersions of PFR-modified GNPs in the production of nanocomposite materials does not require a preliminary removal of the surfactant. Based on the resulting dispersion, the mesoporous carbon/GNPs composite with a developed surface (3000 ? 4000 m2 g?1) was successfully synthesized. It can be used as an electrode material for supercapacitors and an adsorbent of organic and inorganic species for wastewater treatment purposes.
关键词： graphene nanoplatelets,reactive surfactant,self-assembly,nanocomposites,mesoporous carbon,phenol-formaldehyde resin
更新于2025-09-10 09:29:36