Levels Of Ammonia Concentration Research Articles

A-132 Next generation ammonia reagent with improved reagent composition and assay performance

Abstract Background Ammonia is produced by catabolism of protein and other compounds which contain nitrogen. Elevated ammonia levels are toxic for the central nervous system. High plasma ammonia is a prognostic factor for hepatic and kidney disease or inherited metabolic disorders in urea cycle metabolism. The reliable and accurate quantification of ammonia is influenced by assay, reagent, and sample management. Current commercially available GLDH enzyme-based ammonia assay reagents experience high bias between matched Lithium Heparin and K2-EDTA samples, poor accuracy, imprecision at the low end, large HIL (hemolysis, icterus and lipemia) interferences and shorter shelf life. To improve upon the listed deficiencies, we developed an improved GLDH based ammonia assay in a two-part format with improved reagent composition. Methods Ammonia reagent in 2-part format R1 and R2 were assessed for accuracy, precision, interference by HIL reportable range, sensitivity (LoB, LoD, LoQ), shelf life, matched matrix comparison (Lithium Heparin vs K2-EDTA) and method comparison. All testing were performed using Li Heparin plasma samples in Beckman DxC700AU analyzer. Accuracy was tested using Verichem ammonia standards which are ACS ammonia standard material. Twenty-day precision studies were performed using three levels of ammonia concentrations using Bio-Rad Liquichek Ammonia controls and plasma samples. Interference was tested in two ammonia concentrations (40-50 µmol/L) and (200-250 µmol/L) using commercially available spiking material for clinical chemistry assays such as conjugated and unconjugated bilirubin, Intralipid and in-house prepared hemolysate. Infinity Ammonia Reagent on Beckman Coulter AU Chemistry Analyzers was used for method comparison studies Results Next generation ammonia showed good accuracy with Verichem ammonia standards and acceptable within-run and total precision. Studies showed significant improvement in sensitivity and longer shelf life (>18 months). Next generation ammonia is less affected by interferences from icterus (100 mg/dL), lipemia (1000 mg/dL intralipid) and hemolysis (100 mg/dL). Comparison studies show no significant bias between match Lithium Heparin and K2-EDTA matched samples. Conclusions Next Generation Ammonia reagent showed very good overall performance required for reliable and accurate quantification of ammonia in human plasma sample.

Comprehensive protection against ammonia by Cu2+ modified activated carbon

An innovative “material-component-whole” evaluation model was used to assess the overall protective performance of gas masks against ammonia. Coconut shell-based carbon (AC-S), coconut shell-impregnated carbon (ACCu-S), coal-based carbon (AC-C), and coal-impregnated carbon (ACCu-C) were chosen as the adsorbents for this study. The physicochemical characteristics of the activated carbon samples were analyzed through SEM, BET, FT-IR, EA, XPS and XRD tests. This research delves into the breakthrough curves of ammonia gas by the activated carbon and canisters under varying concentrations of ammonia, ambient temperatures, airflow velocities, and relative humidity, also exploring the breakthrough curves of ammonia gas by gas masks under different ammonia concentrations and airflow patterns while considering both dynamic and static adsorption of activated carbon. The empirical results show that increased levels of ammonia concentration, ambient temperature, and airflow velocities lead to decreased protection duration of activated carbon and canisters. Conversely, an elevation in the relative humidity within the ammonia gas stream results in an expansion of the protection time. This study found a linear correlation between the protection time of S and C canisters and the corresponding protection time of the impregnated carbon. Lastly, the protective time of gas masks in sinusoidal airflow mode is highlighted as having a more significant impact.

A novel strategy for integration of oxidation within advanced thermal hydrolysis of sludge

Due to its environmental impact, the growing production of sewage sludge is a prime concern for wastewater treatment plants. In this study, advanced thermal hydrolysis, the combination of thermal hydrolysis and oxygen, was examined to enhance biogas production and overcome the disadvantages of thermal hydrolysis, including sludge colour, high energy consumption, and high level of ammonia concentration in the treated sludge. A mixture of 55 % primary sludge and 45 % waste activated sludge was pre-treated using advanced thermal hydrolysis at 100, 115, 130, and 145 °C with a processing time varied from 5 to 30 min and oxygen pressure from 10 to 30 bar before anaerobic digestion. Advanced thermal hydrolysis process at 145 °C 15 min 20 bar O₂ is the condition that provided the highest biogas yield (439.6 mL/g VS added). At this treatment condition, the concentration of ammonia nitrogen and propionic acid in the treated sludge was sufficiently low (approximately 302 mg/L and 559.7 mg/L, respectively) to minimise adverse effects on anaerobic digestion.

Role of the Deep Eutectic Solvent Reline in the Synthesis of Gold Nanoparticles.

This work presents a mechanistic understanding of the synthesis of small (<3 nm) gold nanoparticles in a nontoxic, eco-friendly, and biodegradable eutectic mixture of choline chloride and urea (reline) without the addition of external reducing or stabilization agents. Reline acts as a reducing agent by releasing ammonia (via urea hydrolysis), forming gold nanoparticles even at trace ammonia concentration levels. Reline also affects the speciation of the gold precursor forming gold chloro-complexes, stabilizing Au+ species, leading to an easier reduction and avoiding the otherwise fast disproportionation reaction. Such a capability is however lost in the presence of large amounts of water, where water replaces the chloride ligands in the precursor speciation. In addition, reline acts as a weak stabilizing agent, leading to small particles (<3 nm) and narrow distributions although agglomerates quickly form. Such properties are maintained in the presence of water, indicating that it is linked to the urea stabilization rather than the hydrogen-bonding network. This work has important implications in the field of green synthesis of nanoparticles with small sizes, especially for biomedical and health care applications, due to the nontoxic nature of the components of deep eutectic solvents in contrast to the conventional routes.

Assessment on Water Quality Parameter and Nutrients Level of Nyatuh River in Relations with Macrobrachium Rosenbergii Prawn Populations.

In order to determine the safety level of water parameters and nutrients in the natural environment of fish and freshwater prawn in Nyatuh River, Terengganu, Malaysia, it is necessary to conduct an assessment of water quality parameters. Due to its important, a study was conducted to assess the water quality parameter and nutrients contents from Nyatuh River of Setiu Terengganu in relations to the population of freshwater prawn, Macrobrachium rosenbergii caught along the Nyatuh River basin. Total of four expeditions and five stations at different tidal condition for the water quality parameter were assessed during the study. From the results achieved, the overall temperature varied between (26.56°C-29.30°C), dissolved oxygen, DO (3.59 mg/L-6.50 mg/L), pH (4.99-7.01), salinity (0.01ppt-4.22ppt), depth (2.71 m-5.54 m) while for ammonia (0.01 mg/L-0.24 mg/L), nitrite (0.01 mg/L-0.05 mg/L) and phosphate (0.01 mg/L-0.12 mg/L). While the number of prawns caught are 176, 160, 102 and 68 for Expeditions 1, 2, 4 and 3, respectively. Possibly, the heterogeneous number of prawns caught is a result of significant differences in water level depth during high tides and low tides, as well as a fluctuation in the ammonia concentration levels in each of the stations and expeditions. For statistical analysis, the temperature showed no significant difference between the expedition, stations and tidal. That is p = 0.280, p > 0.05 and F = 1.206, respectively. While dissolved oxygen, DO, showed no significant difference as well, that is p = 0.714, p > 0.05 and F = 0.737. However, the level of water depth was significantly different between expedition, station and tidal, that is p = 0.000, p < 0.05 and F = 3.120. Ammonia, on the other hand shows no significant difference between expedition, station and tidal, that is p = 0.476, p > 0.05 and F = 0.973. The same goes for nitrite and phosphate concentration. There was no significant difference between expedition, stations and tidal, that is p = 0.569, p > 0.05 and F = 0.879 and p = 0.247, p > 0.05, F = 1.255, respectively. In Expedition 1, the good water quality parameter and very low ammonia concentration resulted in a larger prawn population as compared to other expeditions. The distribution or mixture of prawns caught is heterogeneous at different stations due to the significant differences in water depth and also to the fluctuation in water quality due to varying ammonia levels. In conclusion, the water quality in Nyatuh River fluctuated across expeditions, stations, and tides, as well as significant differences in water level depths between high and low tides. Due to the rapid growth and importance of industrial and aquaculture operations along the river, extra attention should be devoted to avoid the impact of excessive pollutant in order to protect the ecosystem.

Long-Term Effects of Rifaximin on Patients with Hepatic Encephalopathy: Its Possible Effects on the Improvement in the Blood Ammonia Concentration Levels, Hepatic Spare Ability and Refractory Ascites.

Background and Objectives: To investigate the long-term efficacy of rifaximin (RFX) for hyperammonemia and efficacy for refractory ascites in patients with cirrhosis. Materials and Methods: We enrolled 112 patients with liver cirrhosis who were orally administered RFX in this study. Changes in the clinical data of patients were evaluated up to 36 months after RFX administration. The primary endpoint was a change in blood ammonia levels. Secondary endpoints included changes in clinical symptoms, Child–Pugh (CP) score, number of hospitalizations, degree of refractory ascites, adverse events, and the relationship between RFX administration and the renin-angiotensin-aldosterone system. Results: An improved rate of overt hepatic encephalopathy (HE) of 82.7% was observed 3 months after RFX administration, which significantly induced a progressive decrease in blood ammonia concentration and an improved CP score up to 36 months. No serious RFX treatment-related adverse events were observed. 36.5% in patients after RFX administration improved refractory ascites. After RFX administration, patients with satisfactory control of hepatic ascites without addition of diuretic had lower renin concentration than those with poor control (p < 0.01). At less than 41 pg/mL renin concentration, the control of refractory ascites was significantly satisfactory (p < 0.0001). Conclusions: RFX reduced blood ammonia concentration and improved hepatic spare ability and the quality of life of patients with long-term HE to up to 36 months. Our study revealed the effects of RFX against refractory ascites, suggesting that renin concentration may be a predictive marker for assessing ascites control.

Poly[2,5-bis(3-tetradecylthiophen-2-yl) thieno [3,2-b] thiophene] Organic Polymer Based-Interdigitated Channel Enabled Thin Film Transistor for Detection of Selective Low ppm Ammonia Sensing at 25°C

In the present work, we have developed a solution-processable poly (2,5-bis (3-tetradecylthiophen 2yl) thieno(3,2b) thiophene) (PBTTT-C14) based organic thin film transistor, for possible selective sensing the toxic ammonia (NH3) gas at 25°C. This thin-film transistor based sensor makes use of PBTTT-C14 polymer as an organic channel that exhibits highly responsive (>61%) behavior at different levels of ammonia concentrations, even in presence of a mixture of ethanol and butanol gases in a humid environment. The notable changes are observed in the transistor parameters including channel mobility, threshold voltage and the on-off ratio. Interdigitated channels obtained using shadow masking technique enables the device to respond to a low ammonia concentration (<10 ppm). Better sensing capabilities with a detection limit of 2 ppm, the response time of 30 sec and recovery time of 40 sec of exposed ammonia, butanol and ethanol gases have been recorded. The mechanism of sensing has been explained for a better understanding of electrostatic and chemical interaction between gases and PBTTT-C14 semiconductor. Electrical characterizations of the device for the sensing were carried-out in the ambient condition. The device performance has been tested in humid environmental conditions. The fabricated device exhibited enormous potential for ammonia sensing for real-life applications.

Biofilters as Alternative Method for Ammonia Removal in Water Treatment Plant

High level of ammonia concentration in raw water have led to the temporary shutdown of water treatment plant at certain areas of Malaysia especially in Selangor state. The contamination occurred as a result of the impact of industrial activities, agricultural activities and disposal of rubbish into the river. This study was carried out to determine the performance of slow sand biofilters (BioSSF) as an alternative method for the ammonia removal in drinking water treatment plant. Two factors i.e., empty bed contact time (EBCT) (5 to 15 minutes) and ammonia concentration (3 to 5 mg/L) were investigated. The results showed the best ammonia removal percentage was at 15 minutes EBCT with removal percentage of 98.3%. Increasing the ammonia concentration in raw water reduced the BioSSF performance, but the ammonia removal was still below the regulated limits (&lt; 1.5 mg/L). In addition, the BioSSF also have a capability to reduce the turbitidy, chemical oxygen demand, colour and suspended solid. Thus, it proved the BioSSF can be an alternative method for the current conventional water treatment specially to remove the ammonia. Â

Low-Temperature Ionic Layer Adsorption and Reaction Grown Anatase TiO2 Nanocrystalline Films for Efficient Perovskite Solar Cell and Gas Sensor Applications

A low-temperature (90 °C) and directly grown anatase titanium dioxide (TiO2) nanocrystalline film using successive ionic layer adsorption and reaction (SILAR) for perovskite solar cell and gas sensor applications. TiO2 nanocrystalline electron transfer layer (ETL) improves the power conversion efficiency (PCE) of perovskite solar cells due to faster charge transport kinetics as well as slower charge recombination process. The optimized TiO2 nanocrystalline ETL (15 L) demonstrates as high as ~10% PCE with a short circuit current density of 18.0 mA/cm2, open circuit voltage of 0.81 V and fill factor of 66.3% in perovskite solar cells. Furthermore, room-temperature ammonia sensing characteristics of TiO2 nanocrystalline film (25 L) were demonstrated for various concentration levels of ammonia in dry air conditions. A high room-temperature response of 80% was achieved at 100 ppm of ammonia with rapid response and recovery signatures of 30 and 85 s, and nearly fifteen days stability, respectively. The response of the sensor to other gases such as formaldehyde, petrol, ethanol acetone, and ammonia etc, indicated a high selectivity towards volatile organic compounds of ammonia gas. The room temperature operation, with high selectivity, repeatability and fast transition times, suggests potentially useful in flexible and cost-effective production in optoelectrochemical device technology.

An electrochemical method for the determination of concentration and diffusion coefficient of ammonia‑nitrogen gas mixtures

In the present investigation an electrochemical method for the determination of concentration and diffusion coefficient of ammonia in nitrogen (NH3/N2) is proposed by the means of a solid-state amperometric sensor based on yttria-stabilized zirconia (8YSZ) electrolyte. The measured quantity of the studied sensor is limiting current. The experiments are performed for ammonia concentration levels of 0.1–5vol% in the temperature interval of 375–430°C. It is shown that the limiting current level is reached at temperature values not higher than 400°C and it is linearly proportional to the ammonia concentration. This allows obtaining a calibration curve (limiting current vs. ammonia concentration) for the ammonia determination in NH3/N2 mixtures. Using the obtained results and diffusion channel parameters, coefficients of ammonia diffusion in nitrogen can also be calculated. It is found that these values are in a good agreement with table values. It is also found that under experimental conditions the ammonia electrochemical oxidation reaction leads to the formation of N2 rather than N2O or NO. The obtained results demonstrate the possibility of using such amperometric sensor for the analysis of ammonia-gas mixtures where diluent gas is nitrogen or another inert gas.

Porous medium based burner for efficient and clean combustion of ammonia–hydrogen–air systems

Due to its high hydrogen density and extensive experience base, ammonia (NH3) has been gaining special attention as a potential green energy carrier. This study focuses on premixed ammonia–hydrogen–air flames under standard temperature and pressure conditions using an inert silicon-carbide (SiC) porous block as a practical and effective medium for flame stabilization. Combustion experiments conducted using a lab scale burner resulted in stable combustion and high combustion efficiencies at very high ammonia concentration levels over a wide range of equivalence ratios. Noticeable power output densities have also been achieved. Preliminary results of NOx emission measurements indicate NOx concentrations as low as 35 ppm under rich conditions. The remarkable capability of this specific burner to operate efficiently and cleanly at high ammonia concentration levels, which can easily be achieved by partial cracking of NH3, is believed to be a key accomplishment in the development of ammonia fired power generation systems.

Effect of straw size and microbial amendment of litter on certain litter quality parameters, ammonia emission, and footpad dermatitis in broilers

Abstract. This study was conducted to evaluate the impact of litter amendment (microbiological product – Micropan complex) and straw size (unchopped and chopped straw) on pH, moisture level, ammonia emission, and footpad dermatitis in broilers. A total of 1200 1-day-old Ross 308 broilers were randomly allocated to four treatments (2 × 2 factorial arrangement), with four replicates per treatment. Each replicate consisted of 75 as-hatched birds per pen. The first factor consisted of wheat straw – chopped (C) or unchopped (U) – and the second factor was the litter amendment with (WM) or without (OM) Micropan® (enzymatic bacterial product – Eurovix, USA). At 4, 5, and 6 weeks of the trial, the levels of ammonia concentration, moisture content, and pH of litter in each pen were measured. The foot pad lesions were evaluated at 21, 35, and 42 days of age. Broilers reared on chopped straw had significantly better leg condition as expressed by a smaller incidence and severity of footpad dermatitis. The pH value of litter was decreased and footpad quality was significantly improved by Micropan application in broilers kept on chopped and unchopped straw in the sixth week of age. There was no significant effect of Micropan application and straw size on ammonia emission in broiler housing.

Airway inflammation and ammonia exposure among female Palestinian hairdressers: a cross-sectional study

ObjectivesLittle is known about the working conditions and airway inflammation in hairdressers in Palestine. We aimed to investigate if hairdressers in Palestine have a higher level of airway inflammation as...

The Characteristics of Ambient Gases Pollutant, South Korea

In this study, DPNH-sampling technique, indophenol method, gas chromatography-flame ionization detector (GC- FID) and High performance liquid chromatography were applied to conduct three days continuous measurements in areas of Gunsan city, South Korea to detect the concentration of formaldehyde, acetaldehyde, styrene and ammonia emissions level during 21th to 23rd of October 2012. A total 288 samples were collected at six different locations included residential and industrial areas of the city. The sampling was run in the period of 6 hr for three days. With the combination of local meteorological data, including wind direction and speed, temperature and humidity, the result showed that the concentration of ammonia were higher during the afternoon when temperature increases while the values of formaldehyde, acetaldehyde and styrene were high during the night and early morning. The major source of ammonia, aldehydes and styrene were mainly industries chimney with high average concentration. Highest level of ammonia concentration was detected as 125.8 ppb in the atmosphere during the third day 12 pm when temperature raised to 20.1oC. The results indicate that in addition the formaldehyde, acetaldehyde and styrene average levels ranged from 3 to 11 ppb, 1.2 to 5.6 ppb and 4 to 16.2 ppb during sampling time. This pilot study was undertaken to provide reliable information on distribution patterns of gaseous pollutants in ambient air in Gunsan. The results indicated that the values of emitted pollutants concentration investigated in the present study were below the limits that are mandatory in the South Korea guidelines.

Monitoring acidic and basic volatile concentration using a pH-electrode based wireless passive sensor

We present a near-field coupled passive sensor capable of measuring acidic and basic volatile concentration in its surrounding environment. The sensor employs an LC resonant circuit consisting of a spiral inductor connected in parallel with a voltage dependent capacitor (varactor). The volatile detector comprises a hydrogel coated pH-sensitive electrode pair connected in parallel with the varactor. The hydrogel is used as an absorptive medium for the volatiles and acts to contain the electrolyte. On absorption of the acidic or basic volatiles the hydrogel pH changes, which in turn changes the voltage across the pH-sensitive electrode pair shifting the resonant frequency of the sensor. An interrogator coil is inductively coupled to the sensor inductor and remotely tracks the resonant frequency of the sensor. The ability to sense and quantify different concentration levels of ammonia and acetic acid vapor is demonstrated. The sensor has a linear response to the logarithm of the volatile concentration and a detection limit of 1.5ppm and 2ppm for ammonia, and acetic acid vapor, respectively. Effects of varying relative humidity, temperature and hydrogel coating thickness on the sensor's performance are presented. Exhibiting a response time of less than 20min and irreversible operation in a closed environment, the sensor has potential in packaged food condition monitoring.

Design and Implementation of Smart Relay based Remote Monitoring and Controlling of Ammonia in Poultry Houses

aim of this study is the automation of the monitoring and controlling of ammonia concentration in the air of poultry houses by using Smart Relay (SR). Ammonia (NH3) concentration in poultry houses is a production issue of concern, where it is one of the harmful gases that significantly affect the health of birds and growers (through exposing to the high concentration levels of ammonia). The system achieve 24 hours remote monitoring without human intervention through using the communication connection feature of smart relay with the local operator communication networks via its communication interfaces that used along with it in this system. This remote monitoring is achieved through sending and receiving SMS messages from this system to the mobile phone of person in charge of poultry farms and vice versa. General Terms Remote, Monitoring, Controlling, Communication, Message, Flowchart, Program, Software, Hardware, Logical, Threshold value, Exceeding, Critical, Normal, Didactic, proposed system, and Automatic. KeywordsRelay (SR), GSM, SMS, Report, Poultry houses, Litter, Ammonia (NH3), Relative Humidity(RH), Temperature(T), AC Drive, Exhaust fan, Threshold Limit Value (TLV), Automation, Remote Monitoring System (RMS), Mobile phone, and Timer

A highly selective room temperature ammonia sensor using spray deposited zinc oxide thin film

Nanostructured ZnO thin films were deposited on glass substrates at 503K using spray pyrolysis technique and the films were post annealed at 673K in air atmosphere for 3h. The structural, morphological and optical properties of as-deposited and annealed samples were investigated. The annealed films showed uniform spherical morphology in contrast with as-deposited films. XRD patterns of both the annealed and as-deposited films confirmed the polycrystalline nature of the films with hexagonal wurtzite structure. Room temperature ammonia sensing characteristics of annealed films were studied for various concentration levels of ammonia at dry air and humidity conditions. A highest room temperature response of 233 was achieved at 25ppm of NH3 with a response and recovery times of 20 and 25s respectively. The response of the sensor to other gases such as methanol, ethanol, 2-propanol, benzyl alcohol and acetone indicated a high selectivity towards ammonia gas. The room temperature (303K) operation, with high selectivity, repeatability and fast transition times of the sensor together with the low deposition cost suggests suitability for developing a low power cost-effective ammonia sensor.

Ammonia pollution characteristics of centralized drinking water sources in China

The characteristics of ammonia in drinking water sources in China were evaluated during 2005–2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

Effects of ammonia concentration on the thermodynamic performances of ammonia–water based power cycles

The power generation systems using a binary working fluid such as ammonia–water mixture are proven to be the feasible method for utilizing a low-temperature waste heat source. In this work, ammonia–water based Rankine (AWR) regenerative Rankine (AWRR) power generation cycles are comparatively analyzed by investigating the effects of ammonia mass concentration in the working fluid on the thermodynamic performances of systems. Temperature distributions of fluid streams in the heat exchanging devices are closely examined at different levels of ammonia concentration and they might be the most important design consideration in optimizing the power systems using a binary working fluid. The analysis shows that the lower limit of workable ammonia concentration decreases with increasing turbine inlet pressure. Results also show that both the thermal and exergy efficiencies of AWRR system are generally better than those of AWR system, and can have peaks at the minimum allowable ammonia concentrations in the working range of system operation.

Enhanced chemosensing of ammonia based on the novel molecular semiconductor-doped insulator (MSDI) heterojunctions

A series of new molecular semiconductor-doped insulator (MSDI) heterojunctions as conductimetric transducers to NH 3 sensing were fabricated based on a novel semiconducting molecular material, an amphiphilic tris(phthalocyaninato) rare earth triple-decker complex, Eu 2[Pc(15C5) 4] 2[Pc(OC 10H 21) 8], quasi-Langmuir–Shäfer (QLS) film, as a top-layer, and vacuum-deposited and cast film of CuPc as well as copper tetra-tert-butyl phthalocyanine (CuTTBPc) QLS film as a sub-layer, named as MSDIs 1, 2 and 3, respectively. MSDIs 1– 3 and respective sub-layers prepared from three different methods were characterized by X-ray diffraction, electronic absorption spectra and current–voltage ( I– V) measurements. Depending on the sub-layer film-forming method used, α-phase CuPc film structure, β-phase CuPc crystallites and H-type aggregates of CuTTBPc have been obtained, respectively. An increasing sensitivity to NH 3 at varied concentrations in the range of 15–800 ppm, follows the order MSDI 2 < MSDI 3 < MSDI 1, revealing the effect of sub-layer film structures on sensing performance of the MSDIs. In particular, the time-dependent current plot of the MSDI 1, with α-phase CuPc film as a sub-layer, clearly shows an excellent separation of the different ammonia concentration levels and nearly complete reversibility and reproducibility even at room temperature, which is unique among the phthalocyanine-based ammonia sensors thus far reported in the literature. This provides a general method to improve sensor response of organic heterojunctions by controlling and tuning the film structure of sub-layer with appropriate fabrication techniques. On the other hand, the enhanced sensitivity, stability and reproducible response of the MSDI 1 heterostructure in comparison with the respective single-layer films have also been obtained. A judicious combination of materials and molecular architectures has led to enhanced sensing properties of the MSDI 1, in which control at the molecular level can be achieved.