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The Analyst ◽  
2022 ◽  
Author(s):  
Mengru Li ◽  
Ran Li ◽  
Bo Han ◽  
Haojie Ma ◽  
Xueyan Hou ◽  
...  

Tartrazine, as a synthetic food colorant, is harmful to health upon excessive intake. In this work, we developed a simple, sensitive and ultrafast method to detect tartrazine effectively. Specifically, we...


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 297
Author(s):  
Andrea Paut ◽  
Ante Prkić ◽  
Ivana Mitar ◽  
Lucija Guć ◽  
Marijan Marciuš ◽  
...  

The solid-state ion-selective electrodes presented here are based on the FePO4:Ag2S:polytetrafluoroethylene (PTFE) = 1:1:2 with an addition of (0.25–1)% microwave-synthesized hematite (α-Fe2O3), magnetite (Fe3O4), boehmite [γ-AlO(OH)], and alumina (Al2O3) nanoparticles (NPs) in order to establish ideal membrane composition for iron(III) cations determination. Synthesized NPs are characterized with Fourier-Transform Infrared (FTIR) spectroscopy, Powder X-Ray Diffraction (PXRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). The iron oxides NPs, more specifically, magnetite and hematite, showed a more positive effect on the sensing properties than boehmite and alumina NPs. The hematite NPs had the most significant effect on the linear range for the determination of ferric cations. The membrane containing 0.25% hematite NPs showed a slope of −19.75 mV per decade in the linear range from 1.2∙10−6 to 10−2 mol L−1, with a correlation factor of 0.9925. The recoveries for the determination of ferric cations in standard solutions were 99.4, 106.7, 93.6, and 101.1% for different concentrations.


Separations ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 247
Author(s):  
Zheyuan Shi ◽  
Zhu Rao ◽  
Jun Zhao ◽  
Ming Liang ◽  
Tao Zhu ◽  
...  

Polycyclic aromatic hydrocarbon (PAH) derivatives are mutagenic, carcinogenic, teratogenic and bioaccumulative pollutants. Investigations on hydroxylated PAHs (OH–PAHs) and Nitrated PAHs (NPAHs) in surface water are not enough. In this study, optimization and validation of an analytical method targeting nine kinds of OH–PAHs and one kind of nitrated PAH in environmental water samples are presented. The method was validated for linearity, limits of detection and quantification and recovery using spiked matrix. The linear range of most target compounds was 0.1–200 ng∙mL−1. However, the linear range of 1–hydroxy pyrene and 3–hydroxy benzo[a]pyrene started at 1 ng∙mL−1 and the linear range of 1–hydroxy phenanthrene and 9–hydroxy benzo[a]pyrene could not reach 200 ng∙mL−1. All the correlation coefficients (r2) were over 0.997. The instrumental limits of detection (LOD) and method detection limits (MDL) ranged from 0.01 to 0.67 ng∙mL−1 and 1.11 to 2.26 ng∙L−1, respectively. With this method, a lake in Hebei province, China, were screened. Three kinds of target compounds were detected. The average concentration was around 2.5 ng∙L−1, while the highest concentration reached 286.54 ng∙L−1.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1485
Author(s):  
Fei Ge ◽  
Liye Zhao ◽  
Yang Zhang

Surface acoustic wave gyroscopes (SAWGs), as a kind of all-solid-state micro-electro-mechanical system (MEMS) gyroscopes, can work normally under extremely high-impact environmental conditions. Among the current SAWGs, amplitude-modulated gyroscopes (AMGs) are all based on the same gyro effect, which was proved weak, and their sensitivity and intensity of the output are both lower than frequency-modulated gyroscopes (FMGs). However, because FMGs need to process a series of frequency signals, their signal processing and circuits are far less straightforward and simple than AMGs. In order to own both high-sensitivity and simple signal processing, a novel surface acoustic traveling wave gyroscope based on amplitude modulation is proposed, using one-dimensional phononic crystals (PCs) in this paper. In view of its specific structure, the proposed gyroscope consists of a surface acoustic wave oscillator and a surface acoustic wave delay line within a one-dimensional phononic crystal with a high-Q defect mode. In this paper, the working principle is analyzed theoretically through the partial wave method (PWM), and the gyroscopes with different numbers of PCs are also designed and studied by using the finite element method (FEM) and multiphysics simulation. The research results demonstrate that under a 1 V oscillator voltage output, the higher sensitivity of −23.1 mV·(rad/s)−1 in the linear range from −8 rad/s to 8 rad/s is reached when the gyro with three PC walls, and the wider linear range from −15 rad/s to 17.5 rad/s with the sensitivity of −6.7 mV·(rad/s)−1 with only one PC wall. Compared with the existing AMGs using metal dots to enhance the gyro effect, the sensitivity of the proposed gyro is increased by 15 to 112 times, and the linear range is increased by 4.6 to 186 times, even without the enhancement of the metal dots.


2021 ◽  
Author(s):  
Vijayakumar Sathya ◽  
Appadurai Deepa ◽  
Lakshmi Kandhan Sangeetha ◽  
Venkatesan Srinivasadesi ◽  
Shyi-Long Lee ◽  
...  

Abstract Merocyanine dye based fluorescent organic compound has been synthesized for the detection of glutamine. The probe showed remarkable fluorescent intensity with glutamine through ICT. Hence, it is tested for the detection of glutamine using colorimetric and fluorimetric techniques in physiological and neutral pH (7.2). Under optimized experimental conditions, the probe detects glutamine selectively among other interfering biomolecules. The probe has showed a LOD of 9.6 nm at the linear range 20-180 µM towards glutamine. The practical application of the probe is successfully tested in human biofluids.


Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 538
Author(s):  
Nabeel A. Riza ◽  
Nazim Ashraf

The Coded Access Optical Sensor (CAOS) camera is a novel, single unit, full spectrum (UV to short-wave IR bands), linear, high dynamic range (HDR) camera. In this paper, calibrated color target imaging using the CAOS camera and a comparison to a commercial HDR CMOS camera is demonstrated for the first time. The first experiment using a calibrated color check chart indicates that although the CMOS sensor-based camera has an 87 dB manufacturer-specified HDR range, unrestricted usage of this CMOS camera’s output range greatly fails quality color recovery. On the other hand, the intrinsically linear full dynamic range operation CAOS camera color image recovery generally matches the restricted linear-mode commercial CMOS sensor-based camera recovery for the presented 39.5 dB non-HDR target that also matches the near 40 dB linear camera response function (CRF) range of the CMOS camera. Specifically, compared to the color checker chart manufacturer provided XYZ values for the calibrated target, percentage XYZ mean errors of 8.3% and 10.9% are achieved for the restricted linear range CMOS camera and CAOS camera, respectively. An alternate color camera assessment gives CIE ΔE00 mean values of 4.59 and 5.7 for the restricted linear range CMOS camera and CAOS camera, respectively. Unlike the CMOS camera lens optics and its photo-detection electronics, no special linear response optics and photo-detector designs were used for the experimental CAOS camera, nevertheless, a good and equivalent color recovery was achieved. Given the limited HDR linear range capabilities of a CMOS camera and the intrinsically wide linear HDR capability of a CAOS camera, a combined CAOS-CMOS mode of the CAOS smart camera is prudent and can empower HDR color imaging. Applications for such a hybrid camera includes still photography imaging, especially for quantitative imaging of biological samples, valuable artworks and archaeological artefacts that require authentic color data generation for reliable medical decisions as well as forgery preventing verifications.


2021 ◽  
Vol 19 (3) ◽  
Author(s):  
AbduRahman Hosseinifar ◽  
Masoud Ghanei-Motlagh ◽  
Maryam Fayazi

Background: The reliable and easy-to-operate detection of hydrogen peroxide (H2O2) has attracted extensive attention in the fields of biomedicine, food security, and environmental analysis. Objectives: In this work, a novel electrochemical method was proposed for H2O2 monitoring using a carbon paste electrode (CPE) modified with MnO2/sepiolite nanocomposite. Methods: MnO2/sepiolite material was characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) technique. The modified CPE was employed for the amperometric monitoring of H2O2 in human serum samples. Results: Electrochemical data showed that the MnO2/sepiolite-CPE displays a high peak current towards H2O2 oxidation. A linear range from 5 to 700 μM and a low detection limit of 0.8 μM for H2O2 were obtained with the proposed sensor. Besides, the electrode depicted excellent reproducibility and anti-interferant ability, promising the applicability of this electrochemical method in practical analyses. Conclusions: This work introduced a new and effective enzyme-less H2O2 sensor based on the MnO2/sepiolite nanocomposite modified CPE. The suggested sensor showed good sensitivity for the rapid detection of H2O2 in a wide linear range with a low detection limit and satisfactory reproducibility, which made it practical for the analysis of hydrogen H2O2 in real samples.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hongcheng Xu ◽  
Libo Gao ◽  
Haitao Zhao ◽  
Hanlin Huang ◽  
Yuejiao Wang ◽  
...  

AbstractMonitoring biophysical signals such as body or organ movements and other physical phenomena is necessary for patient rehabilitation. However, stretchable flexible pressure sensors with high sensitivity and a broad range that can meet these requirements are still lacking. Herein, we successfully monitored various vital biophysical features and implemented in-sensor dynamic deep learning for knee rehabilitation using an ultrabroad linear range and high-sensitivity stretchable iontronic pressure sensor (SIPS). We optimized the topological structure and material composition of the electrode to build a fully stretching on-skin sensor. The high sensitivity (12.43 kPa−1), ultrabroad linear sensing range (1 MPa), high pressure resolution (6.4 Pa), long-term durability (no decay after 12000 cycles), and excellent stretchability (up to 20%) allow the sensor to maintain operating stability, even in emergency cases with a high sudden impact force (near 1 MPa) applied to the sensor. As a practical demonstration, the SIPS can positively track biophysical signals such as pulse waves, muscle movements, and plantar pressure. Importantly, with the help of a neuro-inspired fully convolutional network algorithm, the SIPS can accurately predict knee joint postures for better rehabilitation after orthopedic surgery. Our SIPS has potential as a promising candidate for wearable electronics and artificial intelligent medical engineering owing to its unique high signal-to-noise ratio and ultrabroad linear range.


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