A Highly Sensitive Fluorescent Sensor for Amitrole Determination in Aqueous Samples

NANO ◽  
2017 ◽  
Vol 12 (07) ◽  
pp. 1750071
Author(s):  
Yue Wang ◽  
Danqun Huo ◽  
Jingzhou Hou ◽  
Junjie Li ◽  
Mei Yang ◽  
...  

A simple yet sensitive fluorescent sensor was reported for amitrole analysis based on integration of gold nanoparticles (AuNPs) and CdTe quantum dots (CdTe QDs) via inner filter effect (IFE). The fluorescence of GSH-coated CdTe QDs can be significantly quenched by AuNPs, and gradually restored in the presence of amitrole. Addition of amitrole induced AuNPs aggregation and decreased their characteristic surface plasmon absorption, which diminished the IFE between them. The sensor platform realized high sensitivity and good reproducibility in low concentration amitrole ranging from 9.5[Formula: see text]nM to 1000[Formula: see text]nM with a detection limit down to 4.75[Formula: see text]nM under the optimized conditions. It also resisted a wide range of interfering counterparts and showed analytical performance comparable to the majority of analytical methods reported in prior studies. We envisioned the first fluorescent amitrole sensor would be potentially useful for low cost on-site amitrole monitoring in real application.

2017 ◽  
Vol 9 (6) ◽  
pp. 1031-1037 ◽  
Author(s):  
Jingtao Liu ◽  
Yu Ding ◽  
Lifei Ji ◽  
Xin Zhang ◽  
Fengchun Yang ◽  
...  

Hexavalent chromium (Cr(vi)) is one of the most toxic heavy metal pollutants in groundwater, and thus the detection of Cr(vi) with high sensitivity, accuracy, and simplicity and low cost is of great importance.


RSC Advances ◽  
2014 ◽  
Vol 4 (87) ◽  
pp. 46437-46443 ◽  
Author(s):  
Hao Li ◽  
Juan Liu ◽  
Manman Yang ◽  
Weiqian Kong ◽  
Hui Huang ◽  
...  

The carbon dots/tyrosinase hybrid as a low-cost fluorescent probe for the detection of dopamine exhibits high sensitivity, stability, and precision.


2020 ◽  
Vol 10 (23) ◽  
pp. 8419
Author(s):  
Adriana Remes ◽  
Florica Manea ◽  
Sorina Motoc (m. Ilies) ◽  
Anamaria Baciu ◽  
Elisabeta I. Szerb ◽  
...  

A novel electrochemical glucose sensor was developed, based on a multiwall carbon nanotubes (MWCNTs)-copper-1,3,5-benzenetricarboxylic acid (CuBTC)-epoxy composite electrode, named MWCNT-CuBTC. The electrode nanocomposite was prepared by a two-roll mill procedure and characterized morphostructurally by scanning electron microscopy (SEM). The CuBTC formed defined crystals with a wide size distribution, which were well dispersed and embedded in the MWCNTs. Its electrical conductivity was determined by four-point probe contact (DC) conductivity measurements. The electroactive surface area, determined using cyclic voltammetry (CV), was found to be 6.9 times higher than the geometrical one. The results of the electrochemical measurements using CV, linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), chronoamperometry (CA) and multiple pulse amperometry (MPA) showed that the MWCNT-CuBTC composite electrode displayed high electrocatalytic activity toward the oxidation of glucose and, as a consequence, very high sensitivity. The best sensitivity of 14,949 µAmM−1cm−1 was reached using MPA at the potential value of 0.6 V/SCE, which was much higher in comparison with other copper-based electrodes reported in the literature. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of an effective glucose sensor.


Author(s):  
Shinnosuke Inoue ◽  
Woon-Hong Yeo ◽  
Jong-Hoon Kim ◽  
Jae-Hyun Chung ◽  
Kyong-Hoon Lee ◽  
...  

Tuberculosis (TB) is an epidemic affecting one-third of the world’s population, mostly in developing and low-resource settings. People having active pulmonary TB are considered highly infectious; therefore, it is critical to identify and treat these patients rapidly before spreading to others. However, the most reliable TB diagnostic methods of bacterial culture or nucleic acid amplification are time-consuming and expensive. The challenge of TB diagnosis lies in highly sensitive and specific screening with low cost. Here, we present an LNA-modified microtip-sensor, which is capable of selectively detecting low-abundance DNA from bacteria. When genomic DNA of Bacillus Calmette-Gue´rin (BCG, a surrogate marker of Mycobacterium bovis), and genomic DNA of Staphylococcus epidermidis (S. epi) are used, the microtip-sensor yields the detection limit of 1,000 copies/mL within 20 minutes. The high sensitivity and specificity approaching nucleic acid amplification methods can potentially overcome the current challenges for rapid TB screening.


Blood ◽  
1989 ◽  
Vol 73 (7) ◽  
pp. 1942-1950 ◽  
Author(s):  
BR Kranz ◽  
E Thiel ◽  
S Thierfelder

Abstract Use of immunocytology for accurate identification of malignant cells in cerebrospinal fluid (CSF) has so far been hampered by high cell requirements of the immunologic methods hitherto used. In an attempt to minimize cell loss in cytopreparation, electrostatic binding of cells to poly-L-lysine (PLL)-coated multispot slides, followed by immunocytochemistry, was investigated. Using optimized conditions of cell attachment and fixation and performing all washing procedures on the slide made multimarker analysis possible even in paucicellular specimens, while preserving excellent cell morphology and yielding high sensitivity in the detection of antigens. In a study of 26 CSF specimens with inconclusive cytomorphology, comprising 335 single marker determinations, we were able to discriminate reliably between resting or activated benign cells and a wide range of types of malignant lymphoid cell. A definitive diagnosis was reached in all cases by one tap only. Malignant meningitis was ruled out in ten specimens and proved in 16, including five in which the type of malignancy could only be determined by immunophenotyping. We conclude that immunocytochemistry on PLL-coated slides constitutes the method of choice for immunologic cell differentiation in CSF, which allows equivocal morphologic findings to be clarified.


2006 ◽  
Vol 45 ◽  
pp. 1828-1833
Author(s):  
Fabio A. Deorsola ◽  
P. Mossino ◽  
Ignazio Amato ◽  
Bruno DeBenedetti ◽  
A. Bonavita ◽  
...  

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.


2012 ◽  
Vol 4 (5) ◽  
pp. 1310 ◽  
Author(s):  
Yamin Luo ◽  
Peng Wu ◽  
Jing Hu ◽  
Shaopan He ◽  
Xiandeng Hou ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4,000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated.


2019 ◽  
pp. 5-12

Factibilidad de integrar split-drain MAGFETs con alta sensibilidad en tecnología CMOS Feasibility to integrate high-sensitivity split-drain MAGFETs in CMOS technology Gerard Franz Santillán Quiñonez, Víctor H. Champac Vilela y Roberto S. Murphy Arteaga Departamento de Engenharia Elétrica, Universidade Federal de Santa Catarina, Campus UniversitárioTrindade, Florianópolis, Santa Catarina, Brasil, C.P. 88040900, e-mail: [email protected] Departamento de Electrónica, Instituto Nacional de Astrofísica, Óptica y Electrónica, Sta. Ma. Tonantzintla, Puebla, México, C.P. 72840. DOI: https://doi.org/10.33017/RevECIPeru2011.0015/ RESUMEN La factibilidad de un Split-Drain MAGFET como sensor magnético ha sido explorada con diversas metodologías, pero sin aprovechar más de un efecto galvanomagnético simultáneamente. Unificando trabajos realizados teórica y experimentalmente, modelos analíticos continuos para la relación entre las fuerzas actuando en la dirección de deflexión y el ángulo de Hall, así como criterios de diseño para incrementar la sensibilidad de un Split-Drain MAGFET son presentados. El análisis propuesto muestra que es posible aprovechar los efectos de deflexión de las líneas de corriente y de magnetorresistencia para incrementar la sensibilidad en un Split-Drain MAGFET. Con un Split-Drain MAGFET con canal considerado como plato de Hall corto, sensibilidades de hasta 59 %/T han sido obtenidas experimentalmente midiendo densidades de flujo magnético desde 90 µT hasta 275 µT. Esto es posible debido a la contribución de los dos efectos galvanomagnéticos considerados. Adicionalmente, un macro modelo SPICE para un Split-Drain MAGFET es propuesto para facilitar su uso en circuitos de mayor complejidad. Con respecto a los resultados experimentales obtenidos, el macro modelo SPICE propuesto tiene un error <1.6 % generando el desbalance entre las corrientes de drenaje. Como un Split-Drain MAGFET es compatible con tecnología CMOS, dominante en circuitos integrados, los resultados obtenidos muestran que es factible usarlo como sensor magnético en sistemas integrados CMOS de alta complejidad, lo cual puede abrir un amplio rango de aplicaciones con bajo costo. Descriptores: MAGFET, split-drain MAGFET, efectos galvanomagnéticos, efecto Hall, magnetorresistencia, sensor magnético. ABSTRACT The feasibility of a Split-Drain MAGFET as magnetic sensor has been explored with several methodologies, but without simultaneously advantaging more than one galvanomagnetic effect. Unifying theorically and experimentally developed works, continuous analytical models for the relationship between forces acting in the deflection direction and for the Hall angle, as well as design criteria to increase the sensitivity of a Split-Drain MAGFET are presented. The proposed analysis shows that it is possible to take advantage of the current-lines deflection and magnetoresistance effects in order to increase the sensitivity of a Split-Drain MAGFET. With a Split-Drain MAGFET with a channel considered as a short Hall plate, sensitivities up to 59%/T have been experimentally obtained measuring magnetic flux densities from 90 µT to 275 µT. This is possible due to the contribution of the two considered galvanomagnetic effects. Additionally, a SPICE macro model for a SplitDrain MAGFET is proposed to facilitate its use in more complex circuits. With respect to the obtained experimental results, the proposed SPICE macro model has an error <1.6 % generating the drain current imbalance. Since a Split-Drain MAGFET is compatible with CMOS technology, dominating in integrated circuits, the obtained results show that it is feasible to use it as magnetic sensor in CMOS integrated systems of high complexity, which opens a wide range of low cost applications. Keywords: MAGFET, split-drain MAGFET, galvanomagnetic effects, Hall effect, magnetoresistance, magnetic sensor.


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