Ammonia Vapor Research Articles

Evaporation-Induced Polyelectrolyte Complexation: The Role of Base Volatility and Cosolvents.

Film formation is a vital step for coating applications where a homogeneous, defect-free solid phase should be obtained, starting from a liquid casting formulation. Recently, an alternative waterborne-coating approach was proposed, based on the formation of a polyelectrolyte complex film. In this approach, an evaporating base induces a pH change during drying that initiates the complexation of oppositely charged polyelectrolytes, followed by further densification. In previous studies, ammonia was used as the evaporative base, leading to relatively fast evaporation and resulting in films showing significant brittleness, which tended to crack at low relative humidity or larger thicknesses. We hypothesize that slower complexation and/or evaporation can reduce the problematic stress build-up in the prepared polyelectrolyte complex coatings. For this reason, we studied the changes in the film formation process when there are different bases and cosolvents. We found that reducing the evaporation rate by changing ammonia to the slower evaporating dimethylamine or by adding DMSO as a cosolvent, led to less internal stress build-up during film formation, which could be beneficial for film application. Indeed, films prepared with ammonia showed cracking after 1 h, while films prepared with dimethylamine only showed cracking after one month. The fast evaporation of ammonia was also found to cause a temporary turbid phase, indicating phase separation, while for the slower evaporating bases, this did not occur. All prepared films remained sensitive to humidity, which poses the next challenge for these promising coatings.

Cadmium Dicyanoaurates and Their Reaction with Ammonia.

The synthesis and crystal structures of two anionic cadmium dicyanoaurate coordination polymers, [nBu4N]6[(Cd4Cl4)2(Au(CN)2)12][CdCl4] (TCCA) and [nBu4N]2[Cd(Au(CN)2)4], and their reaction with ammonia vapour is reported. TCCA and the isostructural [nBu4N]6[(Cd4Br4)2(Au(CN)2)12][CdBr4] form 3-D arrays with [Cd4X4]4+ (X=Cl, Br) cubane clusters linked from each octahedral Cd(II) centre by three bridging [Au(CN)2]- units. TCCA reacts with ammonia with concentrations of 1000 ppm or higher to give a product with a quantum yield of 0.88, while [nBu4N]2[Cd(Au(CN)2)4], which forms a 2-D anionic Cd[Au(CN)2]2 sheet structure with axially pendant [Au(CN)2]- units, reacts with concentrated ammonia vapour to generate Cd(NH3)2[Au(CN)2]2; this has a similar 2-D sheet structure but with axial NH3 units. Vibrational spectroscopy illustrated that the reaction of both Cd/[Au(CN)2]-based materials with ammonia proceeded by breaking Cd-NC bonds. For [nBu4N]2[Cd(Au(CN)2)4], this results in decomposition into [nBu4N][Au(CN)2] ⋅ 0.5H2O and Cd(NH3)2[Au(CN)2]2, while the reaction of ammonia with TCCA is reversible by heating the ammonia-bound sample above 110 °C. Cd[Au(CN)2]2 can be prepared by thermal removal of NH3 units from Cd(NH3)2[Au(CN)2]2.

Study on phenyl series of polymers wrapping of different diameters of semiconducting single-walled carbon nanotubes for ammonia gas sensors

In this study, the fluorene-alt-benzene (PFOB), fluorene-alt-bisbenzene (PFDB), and fluorene-alt-tribenzene (PFTB) were synthesized via Suzuki coupling. The phenyl units in PFDB and PFTB are linked by imine bonds (-CH=N-). These three polymers were employed to selectively sort the semiconducting single-walled carbon nanotubes (sc-SWCNTs) from two types of single-walled carbon nanotubes (SWCNTs) with different tube diameters (Plasma (0.9–1.7 nm) and Hipco (0.8–1.2 nm)). The six polymer/sc-SWCNTs composites were prepared for chemiresistor devices via a simple drop-coasting method for detecting the ammonia vapor. The results indicate that all six devices based on polymer/sc-SWCNTs composites demonstrate excellent sensitivity to ammonia vapor. Additionally, they exhibit a low theoretical detection limit and good reproducibility. The PFTB and PFOB showed higher efficiency of selection of plasma and Hipco, respectively. The corresponding sensors showed a good response to ammonia vapor at 3 ppm (PFTB/sc-SWCNTs (Plasma): 5.8% and PFOB/sc-SWCNTs (Hipco): 5.0%). The results suggest that the specific type of polymer needs to be designed for effectively sort sc-SWCNTs from different SWCNTs. This will enable the fabrication of polymer/sc-SWCNTs composite sensors with better response to ammonia.

Visual detection and efficient capture of hydrogen chloride and ammonia vapours by a sustainable dual emissive metal-organic framework.

A convenient, fast, selective, sustainable detection and capture of hydrochloric acid and ammonia vapours in the solid state with bare eye colour switching is observed by a robust microporous 2D zigzag Zn-MOF based material. Here ESIPT off/on based dual emission alteration has been employed for sensing.

Single ammonia droplet combustion in a high-pressure environment in microgravity

Since ammonia is a carbon neutral fuel, it is expected to be widely utilized in the near future. Although there have been many researches on ammonia combustion, no research has been conducted on ammonia droplet combustion, which is a fundamental research on spray combustion, because ammonia is in a gaseous state at room temperature and atmospheric pressure. This study investigated the combustion characteristics of single ammonia droplets in microgravity for the first time. Single ammonia droplets were formed in high pressure air and were successfully ignited in microgravity. In an early stage of burning, the droplet vaporized with an almost constant vaporization rate of 0.87–1.0 mm2/s. After such a quasi-steady period, the vaporization rate decreased over time. In accordance with the decrease in the vaporization rate, the flame standoff ratio also decreased over time. After that, the droplet exhibited unique phenomena such as droplet disruption, puffing, or droplet re-expansion although the fuel was initially pure. These types of unique behavior are caused by the diffusion of water vapor, a combustion product, to the droplet surface, and dissolution and accumulation of water on the droplet surface. Since water has a lower volatility than ammonia, the concentration of dissolved water at the droplet surface increases rapidly as the droplet diameter decreases. As a result, the vaporization of ammonia is suppressed and the flame standoff ratio decreases. Additionally, as the water concentration at the droplet surface increases, the boiling point at the droplet surface also increases, resulting in superheating of the liquid ammonia and homogeneous bubble nucleation. The growth of bubbles caused droplet disruption, puffing, and droplet re-expansion.

Topology characteristics of liquid ammonia swirl spray flame

The utilization of liquid ammonia in gas turbines can reduce energy loss and start-up time. However, the flash boiling phenomenon and the high latent heat of liquid ammonia make the spray flame difficult to stabilize. Increasing the preheated air temperature or adding a small amount of hydrogen as a piloted fuel are considered as effective methods to enhance the stability. To understand the flame topological structure, simultaneous Mie scattering and planar laser-induced fluorescence of OH (OH-PLIF) techniques were used to visualize the liquid ammonia spray structure and flame region information. Results show that the liquid ammonia swirl spray flame exhibits the flame topological structure of distinct zoning characteristics, including the droplet zone, the mixing zone, and the flame zone. Increasing the preheated air temperature accelerates the evaporation of liquid ammonia, leading to an increase in the local equivalence ratio and radial flame splitting. At lower air temperature conditions, increasing the hydrogen blending ratio has minimal impact on the flame topological structure. However, at higher temperature conditions, hydrogen blending significantly promotes reaction intensity upstream and reduces the flame lift-off height, which makes the mixing zone smaller. In general, to achieve a better flame stability effect, the two factors need to be reasonably matched, which has important reference value for the development of liquid ammonia fueled gas turbine combustors.

Methyl red based metal–organic frameworks for the selective and tuneable sensing of ammonia gas

This work examines a family of UiO-based MOFs built from terephthalic acid and a methyl red linker. The orange-red MOFs show a colourimetric response, changing to dark red with acid vapour, and yellow with base (ammonia) vapour.

An indolium ion-based colorimetric sensor for naked-eye detection of cyanide and ammonia: on-site detection technique for cyanide in natural sources and day-to-day monitoring of food spoilage.

Herein, we developed an easy-to-synthesize, simple colorimetric probe and demonstrated its potential for the detection of anions and amines. The probe was capable of detecting CN- selectively among other anions and could detect the presence of all tested amines. It exhibited obvious colour and spectroscopic changes in the presence of the said analytes. The probe was highly sensitive to CN- ions, which enabled the detection of trace amounts of the aforementioned anion. The detection limit for CN- was found to be 3.98 × 10-8 M, which is below most of the LOD values reported thus far. The sensing was further extended to the solid state by effectively immobilizing the probe in a hydrogel matrix. Moreover, upon exposure to ammonia vapour, noticeable colour changes were observed in a probe-coated paper chip within few minutes. Moreover, the practical application of the probe was demonstrated for both CN- and amines. The probe can serve as a promising alternative for detection of CN- content in food and monitoring of biogenic amines and food freshness.

Impact of spray interaction on ammonia/diesel dual-fuel combustion and emission under engine relevant conditions

This study investigates the combustion characteristics of ammonia and diesel sprays in a constant-volume vessel under conditions typical of internal combustion engines, focusing on the interplay between evaporation dynamics and flame interactions within the framework of the Direct Dual Fuel Stratification (DDFS) concept. Under non-evaporation conditions, ammonia and diesel sprays exhibit comparable evaporation profiles, but under evaporation scenarios, ammonia’s higher evaporation rate results in faster mixing with ambient gas than diesel despite the similar liquid penetration lengths of these two fuels. By utilizing meticulously designed arrangements of diesel and ammonia spray injectors, two distinct interaction scenarios between diesel spray and ammonia spray, early and late interaction, are explored. In the early interaction scenario, fuel-rich ammonia-air mixtures ignite directly by the diesel flame, achieving self-sustained propagation and significant heat release, thereby maintaining a high-temperature region for continuous combustion. Conversely, in late interaction scenarios, rapid ammonia evaporation leads to a fuel-lean ammonia/air mixture that cannot be ignited by the diesel flame, eventually leading to ammonia flame extinction. The study reveals that NOx and N2O emissions are sensitive to the diesel/ammonia flame interaction. N2O emissions, formed predominantly at the forefront of the quenching ammonia flame, pose a significant challenge due to the fast evaporation rate and slow oxidation rate in fuel-lean mixtures. These findings provide insights into the physics of ammonia–diesel combustion, highlighting the challenges and potential strategies for efficient and clean combustion in ammonia-fueled DDFS engines.

Pectin Based Colorimetric Film for Monitoring Food Freshness

The colours of anthocyanins are sensitive to variations in the pH of the environment. The field of food engineering is seeing a rise in the utilisation of anthocyanins obtained from plants to produce new and active packaging film. A pH-sensitive colorimetric film was developed using anthocyanin recovered from the peel of Phaseolus vulgaris (dark red kidney bean) in conjunction with composite pectin derived from citron peel. Additionally, Anthocyanins could be employed as colorimetric markers to identify food degradation, due to their sensitivity towards pH alterations and the production of ammonia gas. Solvent casting process was used to produce the film which changed from pink to brownish with rising pH due to the ammonia vapour that was produced. The antioxidant and antibacterial abilities of the anthocyanin containing smart films were investigated, and both Escherichia coli and Staphylococcus aureus growth was successfully inhibited. The developed film was characterized for its physical properties such as water solubility, moisture content and swelling index. To examine the structure of the films' surface, scanning electron microscopy (SEM) investigation has been carried out. The film indicator active response to pH fluctuation was demonstrated through tests on samples of chicken meat under various settings, allowing for the real-time monitoring of spoiled foods. This makes monitoring perishable goods, easy, affordable, environmentally friendly and biodegradable pH-sensitive indicator with visible colour change.

Surfaces of Atmospheric Droplet Models Probed with Synchrotron XPS on a Liquid Microjet.

ConspectusThe atmosphere is a key part of the earth system comprising myriad chemical species in all basic forms of matter. Ubiquitous nano- and microscopic aerosol particles and cloud droplets suspended in the air play crucial roles in earth's climate and the formation of air pollution. Surfaces are a prominent part of aerosols and droplets, due to the high surface area to bulk volume ratios, but very little is known about their specific properties. Many atmospheric compounds are surface-active, leading to enhanced surface concentrations in aqueous solutions. Their distribution between the surface and bulk may determine heterogeneous chemistry and many other properties of aerosol and cloud droplets, but has not been directly observed.We used X-ray photoelectron spectroscopy (XPS) to obtain direct molecular-level information on the surface composition and structure of aqueous solutions of surface-active organics as model systems for atmospheric aerosol and cloud droplets. XPS is a vacuum-based technique enabled for volatile aqueous organic samples by the application of a high-speed liquid microjet. In combination with brilliant synchrotron X-rays, the chemical specificity of XPS allows distinction between elements in different chemical states and positions within molecular structures. We used core-level C 1s and N 1s signals to identify the alkyl and hydrophilic groups of atmospheric carboxylic acids, alkyl-amines, and their conjugate acids and bases. From this, we infer changes in the orientation of surface-adsorbed species and quantify their relative abundances in the surface. XPS-derived surface enrichments of the organics follow trends expected from their surface activities and we observed a preferential orientation at the surface with the hydrophobic alkyl chains pointing increasingly outward from the solution at higher concentrations. This provides a first direct experimental observation of well-established concepts of surface adsorption and confirms the soundness of the method.We mapped relative abundances of conjugate acid-base pairs in the aqueous solution surfaces from the respective intensities of distinctive XPS signals. For each pair, the protonation equilibrium was significantly shifted toward the neutral form in the surface, compared to the bulk solution, across the full pH range. This represents an apparent shift of the pKa in the surface, which may be toward either higher or lower pH, depending on whether the acid or base form of the pair is the neutral species. The surface shifts are broadly consistent with the relative differences in surface enrichment of the individual acid and base conjugates in binary aqueous solutions, with additional contributions from nonideal interactions in the surface. In aqueous mixtures of surface-active carboxylate anions with ammonium salts at near-neutral pH, we found that the conjugate carboxylic acids were further strongly enhanced. This occurs as the coadsorption of weakly basic carboxylate anions and weakly acidic ammonium cations forms ion-pair surface layers with strongly enhanced local abundances, increasing the probability of net proton transfer according to Le Chatelier's principle. The effect is stronger when the evaporation of ammonia from the surface further contributes to irreversibly perturb the protonation equilibrium, leaving a surplus of carboxylic acid. These surface-specific effects may profoundly influence atmospheric chemistry mediated by aqueous aerosols and cloud droplets but are currently not taken into account in atmospheric models.

A nature pH indicator with high colorimetric response sensitivity for pork freshness monitoring

Smart packaging with colorimetric pH indicators is vital for food quality monitoring. However, synthetic pH-sensitive dyes pose safety hazards, and conventional methods to fabricate pH-sensitive films lack real-time detection. In this study, blueberry anthocyanin (Ant) and petunia dye (PD) were chosen among six natural dyes due to their enhanced pH responsiveness. They were utilized as chromogenic agents, while petunia dye composite film (PDCF) and anthocyanin composite film (AntCF) were synthesized using electrostatic spinning that incorporated natural dye, chitosan (CS), trehalose (TRE), and polyvinyl alcohol (PVA). Finally, a “sandwich” structure pH indicator was created by overlaying two layers of PET on the top and bottom of the composite film and perforating one side. The pH indicator based on PD composite film (PDCF-s) demonstrated superior effectiveness and stability compared to the Ant composite film (AntCF-s) in monitoring pork freshness. The indicators exhibited excellent sensitivity to low concentrations of ammonia vapor, completing the reaction within 2 min. As the pork spoiled, the color of PDCF-s changed visibly from pink to purple, with an ΔE value of 40. Moreover, the ΔE variation remained stable across different conditions. This study innovatively designed “sandwich” pH indicators, providing a promising natural safe dye for smart packaging, and promoting the use of pH-responsive indicators.

The proceeded ammonia release from ammonium nitrate owing to sodium malonate addition: Dependence of RH, acidity and surfactant

The gas-particle partition of ammonia has strong effect on size, composition and hygroscopic property of atmospheric aerosols. However, how chemical reaction drives ammonia evaporation from particle is not well known. In this work, ammonium depletion is used to characterize the ammonia liberation from aqueous ammonium nitrate and sodium malonate/ammonium nitrate aerosols. The addition of sodium malonate promotes more ammonia liberation owing to inter-ingredients reaction. As the relative humidity (RH) decreases, ammonia release is enhanced. Moreover, NH3 evaporation is also impacted by aerosol acidity. At pH 1.93, malonate is directly converted into hydrogen malonate and malonic acid via protonation. Under the neutral/alkaline condition, higher pH is beneficial for component reactions. When cetyltrimethylammonium bromide is added into mixed aerosols, NH3 evaporation becomes slow. These results can provide a new perspective on the evolution mechanism of NH3–NH4+ buffer pairs for multicomponent aerosols.

Advancements in wearable ammonia sensors using polypyrrole/MWCNT coated yarn

In this study, we utilized a dip coating method to modify insulating yarn with polypyrrole and multiwall carbon nanotubes (MWCNTs) to convert it into a conductive yarn. The resulting fabricated conducting yarn underwent thorough characterization through scanning electron microscope, x-ray diffraction pattern, and thermal gravimetric analysis. Subsequently, we examined the ammonia sensing properties of the modified yarn at various stages of its development. Our findings revealed that the combination of MWCNTs followed by polypyrrole modification significantly enhanced the ammonia sensing capabilities compared to using MWCNTs or polypyrrole-coated yarn individually. Specifically, the MWCNTs followed by polypyrrole modified yarn demonstrated an excellent sensing response, remarkable repeatability (up to 24 continuous cycles), quick response time (11 ± 2 s), and recovery time (34 ± 5 s). Additionally, the sensor exhibited good linearity in detecting ammonia vapor concentrations within the range of 20–100 ppm. We also assessed the sensor’s performance with diverse vapors at room temperature, revealing its high selectivity for ammonia. Furthermore, the sensor’s response correlated linearly with yarn length. Remarkably, it demonstrated minimal sensitivity to humidity and exceptional stability over fifty days. These results have the potential to lead to the development of wearable room temperature ammonia sensors, suitable for use in agricultural and industrial chemistry, as well as in environmental, automotive, and medical applications.

Boosting 2,3-butanediol selective dehydrogenation over hierarchical Cu/silicalite-1 via tailoring metal-support interactions

Herein, Silicalite-1 supported Cu catalysts were synthesized by coupling the alkaline treatment and ammonia evaporation methods to synchronously introduce the hierarchical pores and strong metal-support interaction for anaerobic 2,3-butanediol dehydrogenation to acetoin. Characterization results demonstrated that mesoporous structures of resultant Cu/S-x-T can be enhanced by tuning the ammonia dosage in the synthetic solution to boost the formation of -Cu-O-Si- structures and improve the dispersion of copper species simultaneously. The increase in the reduction temperature would induce the reduction of Cu2+ existing in the form of -Si-O-Cu-O-Si-. Highly dispersed Cu0 and abundant Cu2+ sites with an appropriate Cu2+/Cu0 ratio brought about the superior activity of Cu/S-25-300 with a conversion of 78% and selectivity of 92%. A correlation analysis on the catalytic activity and Cu0/Cu2+ site densities as well as IR spectra of adsorbed 2,3-butanediol demonstrated that the synergic catalysis of Cu0 and Cu2+ was primarily responsible for the 2,3-butanediol dehydrogenation. Distinctively, DFT calculations revealed that Cu subnanoclusters was capable of catalyzing the 2,3-butanediol dehydrogenation to acetoin, following a similar reaction mechanism to the dehydrogenation of monohydric alcohols on Cu0 sites due to the size mismatch of reactive sites in reactants and catalytic structures.

Solar-driven chemisorption cogeneration system integrated with thermal energy storage

In this study, a power and cooling cogeneration system is introduced, consisting of a chemisorption cycle, a latent heat thermal energy storage (TES) system employing phase change materials (PCM), and a solar system employing compound parabolic collectors (CPC). The system is targeted at being employed in a residential area in Shiraz City and TRNSYS and MATLAB software environments are utilized to simulate and assess the system. In the system, power is generated by a turbine with the pressure difference elicited through the chemical reaction in the chemisorption cycle. Also, the cooling is produced via the evaporation of ammonia in the evaporator. The effect of the supplied hot source temperature for the reaction in the adsorbent bed was investigated. It was observed that in the 100–200 °C heat source temperature range, the total energy efficiency increased from 0.313 to 0.467 and the COP for the refrigeration process reduced from 0.71 to 0.53. Also, the maximum overall energy and exergy efficiency in this temperature range were 0.46 and 0.405, respectively. Also, at the heat source temperature of 200 °C, the average maximum electrical power and cooling capacity were gauged at 2.7 kW and 14.5 kW, respectively. In the TES system with a volume of 1.5 m3, the maximum achievable capacity was 250 kWh and the solar system showed its highest temperature in July and August. It was observed that heat source temperature augments the production capacity of the system while it reduced the coefficient of performance (COP) of the system. Sustainable development goals (SDG) impact [Display omitted]

Condensation characteristics of ammonia vapor during supersonic separation: A novel approach to ammonia-hydrogen separation

Ammonia has gained significant attention as a prospective hydrogen energy carrier. However, the effective separation of ammonia and hydrogen becomes a crucial aspect after the decomposition of ammonia into hydrogen. In this study, a novel method for ammonia separation is introduced, which leverages the phase transition behavior in supersonic flow. Consequently, this study presents the development of a mathematical model to elucidate the non-equilibrium condensation phenomenon of ammonia, and the accuracy of this model is validated. The simulation results reveal that, in comparison to classical nucleation theory (CNT) and internally consistent classical theory (ICCT), the Lothe-Pound (L-P) nucleation model more accurately characterizes the nucleation process of ammonia at low temperatures. Furthermore, numerical simulations demonstrated that increasing the inlet pressure from 1.2 bar to 1.8 bar led to a 2.66% enhancement in ammonia condensation efficiency. In contrast, raising the inlet temperature from 271 K to 283 K resulted in a decrease in condensation efficiency and a reduction in the radius of the exit droplets, potentially affecting subsequent separation efficiency. When the inlet ammonia molar fraction was elevated from 11% to 14%, the ammonia condensation efficiency increased from 13.7% to 14.5%, with only a minor decrease in outlet droplet radius (from 3.42 × 10−7 m to 3.39 × 10−7 m). These findings indicate that increasing pressure, decreasing temperature, and raising ammonia concentration can all stimulate ammonia condensation. These results have potential implications for the design and optimization of separators.

Evaporation of anhydrous ammonia from small concrete coupons and implications regarding evaporation from a large accidental spill on concrete

AbstractAnhydrous ammonia is transported via ship, rail, and road everyday in the United States as a refrigerated liquid at ambient pressure. As a result, unintential release of a large amount of anhydrous ammonia could result from an accident during transportation. The aim of this paper is to provide a better understanding of the evaporation of anhydrous ammonia from porous media. In our investigation, laboratory‐scale concrete coupons were used as a surrogate for a larger concrete pad that could be present in an event involving an unintentional release of liquid anhydrous ammonia. Concrete coupons sized 5 cm × 5 cm × 1.9 cm were saturated in liquid anhydrous ammonia, and measurements of the subsequent evaporation from the coupons were made in an environmental chamber. The ambient air temperature within the chamber varied from 5 to 45°C, and the relative humidity varied from 5% to 75%. Mass‐difference calculation and Berthelot's reaction were used to determine the average evaporation rate from a concrete coupon across all trials, which was found to be 6.5 ± 1.9 mg/s. To validate these evaporation rates, the remaining ammonia in the concrete coupon was measured for each trial. We found that the time‐integrated calculated evaporation rates correlated well with the total mass of ammonia that was lost from the coupons. In addition, it was found that ambient air temperature and relative humidity had little influence on anhydrous ammonia evaporation from the concrete coupons.

Electroconductive silver nanoparticle composite films for sensing ammonia in the presence of water vapor

Nanocomposite films (NCF) containing silver nanoparticles (AgNPs) separated by thin silica/poly-4-vinylpyridine/polyvinylpyrrolidone polymer layers were fabricated on several substrates by spin coating, dip coating, and drop casting methods. The films exhibit electrical conductivity that changes upon the exposure to moist ammonia and water vapors. Hydrogen bonding of ammonia and water molecules to the silica/polymer layers as well as the direct adsorption of ammonia molecules onto the silver surface accounted for the conductivity changes. Drop casting on nylon filter membranes resulted in the most reproducible films. Optical microscopy, atomic force microscopy, UV-Vis spectroscopy, SEM, and XRD were used for the characterization of the NCF. NCF fabricated with polyvinylpyrrolidone polymer layers exhibited 0.4 ppm limit of detection for ammonia in the presence of interfering water vapor. It is proposed that the films could be further developed as ammonia sensors for environmental and biomedical applications.

Chitosan Film Sensor for Ammonia Detection in Microdiffusion Analytical Devices.

Chitosan films have attracted increased attention in the field of sensors because of chitosan's unique chemico-physical properties, including high adsorption capacity, filmability and transparency. A chitosan film sensor was developed through the dispersion of an ammonia specific reagent (Nessler's reagent) into a chitosan film matrix. The chitosan film sensor was characterized to assess the film's properties by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). A gas diffusion device was prepared with the chitosan film sensor, enabling the collection and detection of ammonia vapor from biological samples. The chitosan film sensor color change was correlated with the ammonia concentration in samples of human serum and artificial urine. This method enabled facile ammonia detection and concentration measurement, making the sensor useful not only in clinical laboratories, but also for point-of-care devices and wherever there is limited access to modern laboratory facilities.