Sensor For Detection Of Ammonia Research Articles

Bibliometric analysis on conducting polymer sensors for ammonia gas detection using Scopus database

AbstractConducting polymers (CPs)‐based sensing materials have emerged as a prominent option for the sensitive detection of gaseous ammonia (NH3) due to their cost‐effectiveness, ease of production, and increased sensing performance. Although more than 1400 articles published in the past decades, no bibliometric analysis which can highlight the publication trend and research clusters within the scope of conducting polymer‐based sensors for ammonia detection (CPAD) is available in the literature. The aim of this bibliometric analysis is to document the research trends of CPAD during the last 27 years, since the inception of the first report on conducting polymer as potential NH3 gas sensor which has been published in 1994. The bibliometric analysis was carried out using VOSviewer and Publish or Perish software to analyze keywords trend, the impact of the scientific community, publishing trends among the authors, institutions, and countries. The review discovered that over 80% of the relevant papers produced after 1994, based on bibliographical examination of 1476 Scopus‐indexed articles. Citation analysis was used to identify key authors and articles that shaped the evolution of this literature. Overall, this bibliometric approach allows us to analyze the evolution of a CPAD field while also offering insights on the field's growing areas.

Ti3C2 MXene-TiO2 hybrid-modified U-bend fiberoptic sensor for improved refractive index sensitivity and ammonia detection

This study introduces the U-shaped evanescent optical fibers (UOFEs), coated with TiO2 and Ti3C2 MXene composites, for refractive index (RI) measurement and ammonia sensing applications. The composites of Ti3C2 MXene multilayers and TiO2 were prepared using a novel preparation technique based on the liquid-phase deposition of (NH4)2TiF6. This is a safe alternative of conventional synthesis techniques in which hazardous HF acid is used. The UOFEs coated with Ti3C2 MXene/TiO2 hybrid films were 12-fold more sensitive to RI with a maximum RI response value of 943–1056%/RIU than bare fibers. In addition, UOFEs exhibited a linear response to ammonia concentrations between 0.5 and 20 ppm at 25 °C. The limit of detection (LOD) of UOFEs for detecting ammonia in water was 1.02 ppm in the detection range of 0–7.5 ppm. The response of UOFEs could be restored by immersing them in water for 5 min. Furthermore, UOFEs demonstrated selective detection of ammonia over aqueous solutions with a concentration of 300 ppm of other routinely used solvents, such as ethanol, methanol, hexane, acetonitrile, acetone, and chloroform. These results demonstrate good reversibility and reproducibility of UOFEs, indicating that UOFE-based sensor for detection of ammonia can be developed with potential biomedical applications.

Electrosynthesized copper polycorroles as versatile materials in double lateral heterojunctions

Metallocorrole derivatives are an emerging class of coordination complexes successfully exploited in different applications, ranging from catalysis to medical field, due to their peculiar tunable properties. Herein, new polycorroles materials are in situ synthesized and deposited on the electrodes in a one-step electrochemical method from 5,10,15-(4-aminophenyl)corrolato]copper(III) as monomer, generating phenazine bridges containing polymer chains. Conductive films are obtained and the film thickness can be controlled by tuning the number of potential scans. However, the nature of the resulting polymer is affected by the electropolymerization conditions: in neat CH2Cl2 the protonation of polymer chains occurs. The role of proton scavenger 2,6-lutidine is worth mentioning, which prevents demetallation of corrole macrocycle. The polycorrole films are further combined with lutetium bis-phthalocyanine to realize double lateral heterojunction (DLH) sensors for ammonia detection, in which organic-organic interface plays a key role in their charge transport properties. The protonation of polycorrole can tune the p- or n-nature of the semiconducting film, and the highest sensitivity obtained with these devices favorably competes with these reported so far for DLH heterojunctions, with a limit of detection as low as 125 ppb for NH3.

Substituted polythiophene-based sensor for detection of ammonia in gaseous and aqueous environment

Substituted polythiophene-based sensor for detection of ammonia in gaseous and aqueous environment

Microwave gas sensor for detection of ammonia at room-temperature

The innovative application of microwave transduction technology in the field of gas sensors make it possible to develop wireless passive room-temperature gas sensor integrated on wearable device. Herein, the ultra-narrowband microwave filter was designed as microwave transducer device, and the microwave sensing measurements were extended to reflected coefficient. Meanwhile, the SnO2/bionic porous (BP) carbon composites based thick film were deposited on the coupled line spacing blank surface via blade coating method. According to the SnO2 nanoparticles were well distributed on BP carbon with abundant micro pores, the gas adsorption and desorption can be enhanced, and the sensor response signal base on microwave transduction was finally improved. Without the influence of temperature and humility, the proposed SnO2/BP carbon microwave gas sensor exhibited excellent NH3 sensing behavior at room temperature including wide concentration range (10–200 ppm), relatively fast response and recovery rate, superior selectivity, as well as good reversibility and stability. More importantly, the dielectric constant of microwave sensor has been proved strongly correlation with injected ammonia concentration. This work further proves the feasibility and frontier of microwave transduction technology in gas sensor application.

A Review on Functionalized Graphene Sensors for Detection of Ammonia.

Since the first graphene gas sensor has been reported, functionalized graphene gas sensors have already attracted a lot of research interest due to their potential for high sensitivity, great selectivity, and fast detection of various gases. In this paper, we summarize the recent development and progression of functionalized graphene sensors for ammonia (NH3) detection at room temperature. We review graphene gas sensors functionalized by different materials, including metallic nanoparticles, metal oxides, organic molecules, and conducting polymers. The various sensing mechanism of functionalized graphene gas sensors are explained and compared. Meanwhile, some existing challenges that may hinder the sensor mass production are discussed and several related solutions are proposed. Possible opportunities and perspective applications of the graphene NH3 sensors are also presented.

Low cost, flexible and disposable SnSe2 based photoresponsive ammonia sensor for detection of ammonia in urine samples

A low cost, flexible, disposable sensing platform which can detect excess ammonia in biological fluids with an enhanced response is of utmost importance in medical diagnostics for early detection of kidney dysfunction, gastrointestinal bleeding, urinary tract related diseases. This report is the first demonstration of direct growth of 2D Tin Diselenide (SnSe2) on cellulose paper by the hydrothermal method for enhanced photoresponsive ammonia detection in urine samples. X-Ray Diffraction (XRD) and Raman studies confirmed the formation of SnSe2 while field emission scanning electron microscopy (FESEM) studies revealed the uniform distribution of SnSe2 nanoflakes on cellulose paper. The SnSe2 based sensor, when irradiated with Near Infra Red (NIR) light exhibited excellent responsivity, detectivity and external quantum efficiency of 70 mA/W, 11 × 107 jones and 4.5% respectively. Furthermore, the photoresponsive sensor responded to a wide range of ammonia concentrations (50μM - 500μM), with a sensitivity of 0.93 m μM−1 in comparison to 0.73 m μM−1 (without illumination) and a limit of detection (LOD) of 11.3μM which is far more superior in performance than sensors fabricated using sophisticated techniques. Motivated by this enhanced response of the sensor to ammonia in the aqueous medium, it was further employed in detecting ammonia in human urine samples. The mechanism of detection can be attributed to NIR induced oxygen desorption on the surface of 2D- SnSe2, hence creating more vacant sites for interaction with ammonia molecules. The strategy presented in this work could be a step ahead in developing low cost, point-of-care diagnostics to detect various diseases.

Highly sensitive and selective liquid crystal optical sensor for detection of ammonia.

Ammonia detection technologies are very important in environment monitoring. However, most existing technologies are complex and expensive, which limit the useful range of real-time application. Here, we propose a highly sensitive and selective optical sensor for detection of ammonia (NH3) based on liquid crystals (LCs). This optical sensor is realized through the competitive binding between ammonia and liquid crystals on chitosan-Cu2+ that decorated on glass substrate. We achieve a broad detection range of ammonia from 50 ppm to 1250 ppm, with a low detection limit of 16.6 ppm. This sensor is low-cost, simple, fast, and highly sensitive and selective for detection of ammonia. The proposal LC sensing method can be a sensitive detection platform for other molecule monitors such as proteins, DNAs and other heavy metal ions by modifying sensing molecules.

Acousto-electronic gas sensor based on mushroom mycelial extracts

The main problem in the development of acousto-electronic gas sensors is the search for materials which are sensitive to the presence of different gases. For this purpose in this paper we suggest the use of piezoelectric quartz resonators coated by the mycelium-origin films of the mushroom Lentinula edodes strain F-249, which were cultivated in a synthetic medium. The extract of mycelium was deposited on the surface of the resonator. Measurement of the frequency dependence of the complex electrical impedance of the resonator allowed us to evaluate the density, elastic constants, and mass of the films under test. The influence of different gases, such as ammonia, formaldehyde, ethylacetate, and volatile liquids: acetone, acetic acid, chloroform on the physical properties of the extracts of Lentinula edodes mushroom mycelium was investigated. The results have shown that this material prepared according to different technological procedures is suitable as a sensitive layer for development of gas sensors for detection of ammonia, formaldehyde, and ethylacetate.

High sensitivity sol-gel silica coated optical fiber sensor for detection of ammonia in water.

A high sensitivity ammonia sensor based on a tapered small core singlemode fiber (SCSMF) structure for measurement of ammonia concentration in water is reported. Two tapered SCSMF fiber structures with different waist diameters of 23 µm and 13.5 µm are fabricated by using a customized microheater brushing technique. The silica based material prepared by the sol-gel method is used as a coating applied to the surface of the tapered fiber structures. To investigate the influence of the coating thickness on the sensitivity to ammonia in water, silica coatings with different thicknesses (2-pass and 8-pass coatings) are deposited on the surface of the fiber sensor with a waist diameter of 23 µm. Experiments demonstrate that the sensor with a thicker (8-pass) silica coating shows better sensitivity of 0.131 nm/ppm to ammonia compared to that of 0.069 nm/ppm for the thinner silica coating (2-pass). To further improve the sensor sensitivity, the taper waist diameter is reduced. For an 8-pass coating (249nm at the taper waist section) applied to a tapered SCSMF structure based fiber sensor with a reduced waist diameter of 13.5 µm. Experimental results show that the sensitivity to ammonia is significantly improved to 2.47nm/ppm. The best measurement resolution for ammonia concentration in water is estimated to be 4 ppb while the response and recovery times are less than 2 and 5 minutes respectively. The proposed sensor also offers good performance in terms of repeatability and good selectivity for sensing ammonia compared to that of other common ions and organic molecules in water.

Performance improvement of macroporous polypyrrole sensor for detection of ammonia by incorporation of magnetite nanoparticles

In this work, polystyrene spheres were employed as templates to prepare polypyrrole inverse opal films on the surface of platinum electrodes. The facilitated access for both outer and inner active sites, as well as the exhibited electrochemical behaviour, turned macroporous PPy into a material more suitable than bulk PPy for electrochemically determining ammonium in samples. However, independently of employing bulk or macroporous polypyrrole, the loss of conductivity suffered by the polymer during the mediating process led to an irreversible increase of the electrical resistance that compromised the sensor's analytical performance. Here, it is shown that the incorporation of magnetite nanoparticles into the walls of the polypyrrole inverse opal films generated a protective effect. This increased the stability of the macroporous mediator due to the preservation of the polaron state, as shown by Raman spectroscopy experiments. Finally, the interaction between polypyrrole and magnetite also positively affected the observed analytical parameters, improving linear range, detection limit and sensitivity of the ammonium sensor.

Fiber optic gas sensors with vanadium oxide and tungsten oxide nanoparticle coated claddings

Fiber optic gas sensors with nanoparticles of V2O5 and WO3 as the cladding of a PMMA fiber have been proposed in this work. The spectral response of these sensors for detection of ammonia, methanol and ethanol under various concentrations has been studied at room temperature. The time response characteristics of the sensors are also presented.

An optical technique for fast and ultrasensitive detection of ammonia using magnetic nanofluids

We report a simple, in-expensive, portable, and ultrasensitive optical sensor for detection of ammonia in parts per million levels using magnetic nanofluids. The sensor produces visually perceptible color changes, in the presence of ammonia, due to the changes in the lattice periodicity of 1-dimensional array of droplets. The penetration of ammonia into the diffused electric double layer around the emulsion droplet causes significant blue shift in the diffracted Bragg peak. The mechanism of the blue shift is probed by measuring the subtle changes in the intermolecular forces in the presence of ammonia. The present approach is useful for online monitoring of ammonia.

PH-indicators doped polysaccharide LbL coatings for hazardous gases optical sensing

Sensitive layer-by-layer (LbL) coatings for optical detection of gaseous NH3 and HCl were prepared by self-assembly of oppositely charged polysaccharides (chitosan and λ-carrageenan) followed by doping LbLs with pH-sensitive dyes – bromothymol blue (BTB) and Congo red (CR). It has been shown that CR, being an amphoteric dye, diffuses into LbL films regardless of the charge of the outermost polyelectrolyte layer, and the dye loading increases linearly with the LbL film thickness, whereas BTB diffuses into LbL films only when the outermost layer is positively charged, and linearity between dye loading and film thickness holds only up to 8–12 double layers (DLs) deposited. Formation of dye-doped LbL coatings at the surface of K+/Na+ ion-exchanged glass has allowed fabrication of composite optical waveguide (OWG) gas sensor for detection of ammonia and hydrochloric acid vapors. The response time of BTB-doped composite OWG for ammonia detection was below 1s, and the detection limit was below 1ppm. CR-doped OWG sensors have shown high sensitivity to HCl vapor but slow relaxation time (up to several hours for 12DL LbL films).

Fabrication and calibration of Oxazine-based optic fiber sensor for detection of ammonia in water

This paper presented the fabrication and calibration of a clad-modified evanescent based plastic optical fiber (POF) sensor for the detection of ammonia in both stagnant and dynamic aqueous media. This optochemical sensor was based on Oxazine 170 perchlorate (sensing material) and polydimethylsiloxane (PDMS) (protective material) thin layers. A special chemical solution was developed for the etching removal of cladding and a methodology for trapping moisture was exercised. Experimental results on dissolved ammonia detection exhibited short response time (≤10 s), low detection limit (minimum detection limit 1.4 ppm), high sensitivity, and excellent reversibility (over 99%).

Surface Acoustic WaveAmmonia Sensors Based on ST-cut Quartz under Periodic Al Structure

Surface acoustic wave (SAW) devices are key components for sensing applications. SAW propagation under a periodic grating was investigated in this work. The theoretical method used here is the space harmonic method. We also applied the results of SAW propagation studied in this work to design a two-port resonator with an Al grating on ST-cut quartz. The measured frequency responses of the resonator were similar to the simulation ones. Then, the chemical interface of polyaniline/WO3 composites was coated on the SAW sensor for ammonia detection. The SAW sensor responded to ammonia gas and could be regenerated using dry nitrogen.

Chemical Treatment Influence on the Glass Substrate to the Growth of V2O5/PANI Thin Film

AbstractGrowth of the vanadium pentoxide xerogel in the presence of the polyaniline thin film (V2O5/PANI) in different chemical treatment on substrate are presented. The in situ characterization studies revealed the presence of a lamellar structure for the V2O5/PANI hybrid material. The intercalation reaction was evidenced on the basis of the increase in the d-spacing as well as the displacement of the absorption bands toward lower energy levels. The growth of V2O5/PANI thin film, from direct reaction, on glasses substrate using pre-treated with cationic surfactant cetyl pyridinium chloride (CPC) and cetyl trimethylammonium bromide (CTAB) presented layers with a surface homogeneous. The UV/ozone and RCA treatment showed that the film had low adhesion on substrate compared with CPC and CTAB treatment. Furthermore, these results suggests that the CTAB and CPC treatment can be used, further, for V2O5/PANI LbL films using V2O5 gel as first layer as well as a promising candidate for applications as sensor for ammonia detection in poultry shed.

Preliminary Study of the Interaction of Metal Nanoparticle-containing Poly-p-xylylene films With Ammonia

G. Sergeev, V. Zagorsky, M. Petrukhina, S. Zav’yalov, E. Grigor’ev and L. Trakhtenberg, Anal. Commun., 1997, 34, 113 DOI: 10.1039/A700431A

Gold-Loaded Tungsten Oxide Sensor for Detection of Ammonia in Air

Abstract Among various noble-metal loaded WO3 sensor elements, the one loaded with Au showed the best NH3 sensing performance in sensitivity and response rate at 450 °C. It could detect NH3 in air over a wide concentration range from 5 ppb to 50 ppm. The optimum Au loading was 0.8 wt%.