| 1. |
- Aghoutane, Youssra, et al.
(författare)
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Development of a molecularly imprinted polymer electrochemical sensor and its application for sensitive detection and determination of malathion in olive fruits and oils
- 2020
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Ingår i: Bioelectrochemistry. - : Elsevier. - 1567-5394 .- 1878-562X. ; 132
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Tidskriftsartikel (refereegranskat)abstract
- Malathion (MAL) is an organophosphorus (OP) insecticide. It is a cholinesterase inhibitor, 15 which can pose serious health and environmental problems. In this study, a sensitive and 16 selective molecular imprinted polymer (MIP) based on screen-printed gold electrodes (Au-17 SPE) for MAL detection in olive oils and fruits, was devised. The MIP sensor was prepared 18 using acrylamide as the functional monomer and MAL as the template. Subsequently, the 19 morphology of the electrode surface was studied by scanning electron microscopy (SEM) and 20 atomic force microscopy (AFM). The electrochemical characterization of the developed MIP 21 sensor was performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), 22 and electrochemical impedance spectroscopy (EIS) techniques. The operational repeatability 23 and stability of the sensor were studied. It was found to have a dynamic concentration range 24 of (0.1 pg mL-1-1000 pg mL-1) and a low limit of detection (LOD) of 0.06 pg mL-1. 25 Furthermore, the sensor was employed to determine MAL content in olive oil with a recovery 26 rate of 87.9% and a relative standard deviation of 8%. It was successfully applied for MAL 27 determination in real samples and promise to open new opportunities for the detection of OP 28 pesticides residues in various food products, as well as in environmental applications.
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| 2. |
- Saidi, Tarik, et al.
(författare)
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Non-invasive prediction of lung cancer histological types through exhaled breath analysis by UV-irradiated electronic nose and GC/QTOF/MS
- 2020
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 311
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Tidskriftsartikel (refereegranskat)abstract
- Lung cancer (LC) is one of the most lethal diseases from the last decades. Accurate diagnosis of LC histology could lead to the prescription of personalized medical treatment to the affected subjects, which could reduce the mortality rate. We present here an experimental study performed in the pulmonology units of three hospitals from Morocco to non-invasively detect LC and predict LC histology via the analysis of the volatile organic compounds (VOCs) emitted through breathing. Gas chromatography coupled to a quadrupole time-of-flight mass spectrometer (GC/QTOF/MS) employed to detect the breath VOCs, revealed 30 discriminative VOCs in the breath of healthy subjects and LC patients; among them, 4 unique breath VOCs were found for the first time in the breath of LC patients, and could be used as new biomarkers for future LC diagnosis. Besides, an electronic nose (e-nose) system using a novel sensing technique in breath analysis, based on UV-irradiation of the gas sensors, was employed to characterize the overall composition of the collected breath samples, providing a satisfactory discrimination between the breath patterns of LC patients and healthy subjects. Importantly, the e-nose could further discriminate with high accuracy between the two types of LC (non-small cell LC and small cell LC), as well as between two of the major subtypes of non-small cell LC, namely squamous cell carcinoma (SCC) and adenocarcinoma (ADC). The reported results prove that breath analysis with chemical gas sensors and analytical techniques can provided an accurate mean for the non-invasive diagnosis of LC and LC histology.
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| 3. |
- Bouchikhi, Benachir, et al.
(författare)
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Formaldehyde detection with chemical gas sensors based on WO3 nanowires decorated with metal nanoparticles under dark conditions and UV light irradiation
- 2020
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 320
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Tidskriftsartikel (refereegranskat)abstract
- We report results of formaldehyde gas (CH2O) detection under dark conditions and UV light irradiation with pristine tungsten trioxide nanowires (WO3 NWs) and metal nanoparticles decorated WO3 NWs gas sensing layers. The resistive layers were deposited by one step aerosol assisted chemical vapor deposition (AACVD) on commercial alumina substrates with 10-pair interdigitated platinum electrodes. The elaborated gas sensors, based on pristine WO3 and on WO3 decorated with Au, Pt, Au/Pt, Ni and Fe nanoparticles, were investigated towards three concentrations of formaldehyde gas (5, 10 and 15 ppm) under dark conditions and under UV light irradiation at the wavelength of 394 nm. Two main effects were observed: firstly, under UV light irradiation the response time for CH2O desorption was significantly reduced with the exception of the nanomaterial with Fe NPs dopant; secondly, the gas induced baseline shift was reduced under UV light irradiation conditions. These results can be explained by the additional energy induced by the UV light, accelerating the adsorption-desorption processes. The results obtained confirmed that both the decoration of WO3 NWs with selected metal nano particles as well as sensors operation under UV light irradiation are a practical and affordable way to enhance gas sensing towards formaldehyde detection, although both strategies applied together did not introduce an amplified synergetic effect.
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| 4. |
- Diouf, Alassane, et al.
(författare)
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An electrochemical sensor based on chitosan capped with gold nanoparticles combined with a voltammetric electronic tongue for quantitative aspirin detection in human physiological fluids and tablets
- 2020
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Ingår i: Materials science & engineering. C, biomimetic materials, sensors and systems. - : ELSEVIER. - 0928-4931 .- 1873-0191. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- Inflammatory diseases increase has recently sparked the research interest for drugs diagnostic tools development. At therapeutic doses, acetylsalicylic acid (ASA or aspirin) is widely used for these diseases' treatment. ASA overdoses can however give rise to adverse side effects including ulcers, gastric damage. Hence, development of simple, portable and sensitive methods for ASA detection is desirable. This paper reports aspirin analysis in urine, saliva and pharmaceutical tablet using an electrochemical sensor and a voltammetric electronic tongue (VE-Tongue). The electrochemical sensor was fabricated by self-assembling chitosan capped with gold nanoparticles (Cs + AuNPs) on a screen-printed carbon electrode (SPCE). It exhibits a logarithmic-linear relationship between its response and the ASA concentration in the range between 1 pg/mL and 1 mu g/mL. A low detection limit (0.03 pg/mL), good selectivity against phenol and benzoic acid interference, and successful practical application were demonstrated. Qualitative analysis was performed using the VE-Tongue based unmodified metal electrodes combined with two chemometric approaches to classify urine samples spiked with different aspirin concentrations. Partial least squares (PLS) method provided prediction models obtained from the data of both devices with a regression correlation coefficient R-2 = 0.99. Correspondingly, the SPCE/(Cs + AuNPs) electrochemical sensor and VE-Tongue could be viable tools for biological analysis of drugs.
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| 5. |
- Kwiatkowski, Andrzej, et al.
(författare)
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Assessment of Electronic Sensing Techniques for the Rapid Identification of Alveolar Echinococcosis through Exhaled Breath Analysis
- 2020
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 20:9
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a proof-of-concept study showing the potential of a chemical gas sensors system to identify the patients with alveolar echinococcosis disease through exhaled breath analysis. The sensors system employed comprised an array of three commercial gas sensors and a custom gas sensor based on WO3 nanowires doped with gold nanoparticles, optimized for the measurement of common breath volatile organic compounds. The measurement setup was designed for the concomitant measurement of both sensors DC resistance and AC fluctuations during breath samples exposure. Discriminant Function Analysis classification models were built with features extracted from sensors responses, and the discrimination of alveolar echinococcosis was estimated through bootstrap validation. The commercial sensor that detects gases such as alkane derivatives and ethanol, associated with lipid peroxidation and intestinal gut flora, provided the best classification (63.4% success rate, 66.3% sensitivity and 54.6% specificity) when sensors’ responses were individually analyzed, while the model built with the AC features extracted from the responses of the cross-reactive sensors array yielded 90.2% classification success rate, 93.6% sensitivity and 79.4% specificity. This result paves the way for the development of a noninvasive, easy to use, fast and inexpensive diagnostic test for alveolar echinococcosis diagnosis at an early stage, when curative treatment can be applied to the patients.
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| 6. |
- Saidi, Tarik, et al.
(författare)
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Exhaled breath gas sensing using pristine and functionalized WO3 nanowire sensors enhanced by UV-light irradiation
- 2018
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 273, s. 1719-1729
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Tidskriftsartikel (refereegranskat)abstract
- The development of advanced metal-oxide-semiconductor sensing technologies for the detection of Volatile Organic Compounds (VOCs) present in exhaled breath is of great importance for non-invasive, cheap and fast medical diagnostics. Our experimental studies investigate the effects of operating temperature selection and UV-light irradiation on improving the response of WO3 nanowire sensors towards exhaled breath exposure. Herein, six WO3 nanowire sensors (both pristine and doped with a range of metal nanoparticles such as Pt, Au, Au/Pt, Ni and Fe) were synthesised via Aerosol-Assisted Chemical Vapour Deposition (AACVD) and characterized by means of Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX-ray). Breath measurements were performed in the dark and under UV-light irradiation at various sensor operating temperatures. The results demonstrate that UV-light irradiation combined with the optimisation of the sensors' operating temperature can greatly enhance the sensors' responses towards breath exposure.
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