Determination Of Ammonia Research Articles

UPLC-UV Method for the Quantification of Free Amino Acids, Bioactive Amines, and Ammonia in Fresh, Cooked, and Canned Mushrooms

Mushrooms are valued due to health-promoting properties and small environmental footprint. The simultaneous determination of free amino acids (17), amines (10), and ammonia in fresh, cooked, and canned Agaricus bisporus was investigated. An AQC-derivatization method was developed and validated. Norvaline was an adequate internal standard. The method was green, fast, and fit for the purpose (quantification limits, 0.14–1.92 mg/100 g; recoveries, 80–110%; repeatability, < 10%; reproducibility, < 15%). Fifteen amino acids were detected in fresh mushroom: alanine and glutamic acid were prevalent (~ 20%) followed by proline. Spermidine was the only amine detected (6.4–8.5 mg/100 g). Ammonia was present at low levels (2.8–5.5 mg/100 g). High amounts of these amino acids and spermidine warrant important health-promoting properties. The levels of amino acids, amines, and ammonia varied among lots from the same source, suggesting the influence of production conditions. During thermal processing, changes were observed: cooking affected the least (losses mainly of glutamic acid, arginine, glycine, serine, threonine, proline, and alanine, ~ 50%). Spermidine and ammonia were not affected. During canning, the losses were higher (~ 70%) for glutamic acid, serine, valine, proline, arginine, glycine, and aspartic acid. There were losses of ammonia (39%) and spermidine (24%). A two principal component model explained 97.8% of the variance and it was able to separate fresh from processed mushroom. Hierarchical cluster analysis confirmed the potential of using amines and amino acids to separate fresh from processed mushroom.

Development of the PANI/MWCNT Nanocomposite-Based Fluorescent Sensor for Selective Detection of Aqueous Ammonia.

The present work reported the polyaniline (PANI) and multiwalled carbon nanotube (MWCNT)-based nanocomposite as a sensing material for the determination of aqueous ammonia by the enhanced fluorescence method. The excitation wavelength-dependent photoluminescence (PL) intensity has shown dual emission peaks at 340 and 380 nm that correspond to two different excitation energy states. The pH-based PL intensity and zeta potential variation were analyzed to optimize the suitable medium for aqueous ammonia sensing. Zeta potential was found to shift from 4 to −21 mV upon changing the pH of the the solution from acidic to alkaline medium. The fluorescence intensity of PANI/MWCNTs was found to increase upon increasing the pH from 3.0 to 6.0 (acidic region) and exhibits a plateau upon further increasing the pH from 7.0 to 12 (basic region). The PANI/MWCNT composite has shown a linear response to aqueous ammonia concentration varying from 25 to 200 μM with a correlation coefficient (R2) of 0.99 and a limit of detection of 15.19 μM. The presence of relevant interference molecules and physiological ions had no influence on the detection of aqueous ammonia. Field-level study demonstrated that the level of aqueous ammonia can be determined selectively by using the PANI/MWCNT composite for various applications. The mechanism for the selective detection of aqueous ammonia is deliberated in detail.

Development of a Method for Assessing Helicobacter pylori Activity Based on Exhaled Air Composition with the Use of an Array of Piezoelectric Chemical Sensors

Currently, patients with stomach and duodenum diseases should be examined using diagnostic tests for Helicobacter pylori infection. Diagnostic methods available in the arsenal of clinicians make it possible to identify Helicobacter pylori in almost 100% of cases. A competent approach to the selection of a diagnostic test provides high-quality, timely, and economical verification of the pathogen. The paper provides information on the currently available diagnostic procedures for the detection of Helicobacter pylori infection and the results of the diagnosis of helicobacteriosis based on the activity of urease in saliva. The main area of research is the development of an analytical method based on the quantitative determination of ammonia and the detection of amines and aliphatic acids in exhaled air using signals from an array of diverse piezoelectric chemical sensors. Simple data processing algorithms were applied, and qualitative and quantitative decision-making criteria were substantiated. The method of analysis using chemical sensors is characterized by high specificity (96% for ammonia) and sensitivity (90%); it does not require special sample preparation and is indispensable in large-scale studies and personal monitoring and for choosing treatment tactics.

Selective determination of ammonia, ethanol and acetone by reduced graphene oxide based gas sensors at room temperature

This work reports a new technique for the selective determination of three organic vapors– ammonia, ethanol and acetone by employing two resistive sensors. These two resistive sensors are based on reduced graphene oxide (RGO) and RGO– rosebengal (RB) composites. The chemically synthesized RGO and RGO–RB based sensors were tested for four different concentrations of ammonia (400–2800 ppm) and two different concentrations (1000, 2000 ppm) of ethanol and acetone each, at room temperature. The RGO sensor was found to exhibit response of 10.3% to 25.3% to 400–2800 ppm of ammonia, 1.01% to 1.15% to 1000 and 2000 ppm of acetone respectively, and 1.05% to 1.56% to 1000 and 2000 ppm of ethanol respectively. The RGO–RB composite-based sensor exhibited an enhanced response ranging from ~17% to 36.6% for 400–2800 ppm of ammonia, 1.6% to 3.2% for 1000 and 2000 ppm of acetone and 1.1% to 1.7% for 1000 and 2000 ppm of ethanol at room temperature. An algorithm, based on the soft margin classifier was developed to accurately determine the concentrations of all the three organic vapors. The initial 100 s of the response values of both the sensors for all the targeted vapors were considered for this purpose. This resulted into classification of all the concentrations of the three organic vapors much before the full-scale response of the sensors. It is believed that this work will aid in development of portable devices comprising of array of sensors having the capability of determining the vapors and their concentrations accurately.

Rapid Determination of Ammonia in Biological Samples by GC-MS Derivatization Method.

Objective To establish a qualitative and quantitative method to determine ammonia in biological samples by gas chromatography-mass spectrometry （GC-MS）. Methods A heptafluorobutyryl chloride derivatization method was used. GC-MS was used for determination. The effects of different pH conditions, derivatization temperature, time and different extraction solvents on the test results were investigated. The pretreatment conditions were optimized. Results This method could accurately detect the ammonia content in blood, and the limit of detection was determined to be 0.1 μg/mL. The target component showed good linearity in the range of 0.5-200.0 μg/mL （R2=0.987 7）. The relative standard deviation range of intra-day precision was 2.59%-3.88%. The relative standard deviation range of inter-day precision was 3.21%-3.76%. Conclusion The method showed good sensitivity, stability and specificity, therefore can be used for forensic toxicology analysis and clinical biochemical detection.

Improvement of ruminal feed fermentation by addition of eucalyptus based mix essential oil

In vitro fermentation methodology was used in this research to explore the effect of mix essential oil (MEO) of eucalyptus (Melaleuca leucadendra (L.) and pine (Pinus merkusii (Jungh. and de Vriese), in ratio 3:1, on feed digestibility and parameter of ruminal feed fermentation. Mix essential oil was added and mix with feed particle to meet the end concentration of 100 μl/L of fermentation media. Incubation was done at 39°C for 24 h. Upon finished the incubation, gas produced were sampled for methane analysis. Residual feed was collected by filtration and then ben analysed the dry matter (DM) and organic matter (OM) content for calculation of DM and OM digestibility. Meanwhile filtrate also collected for determination of pH, ammonia, protozoa number and microbial protein synthesis. Data analysis showed MEO addition did not affect pH, ammonia concentration, DM and OM digestibility. Addition of MEO reduced methane production 24.62% (P<0.05), and increased microbial protein synthesis (P<0.05) from 133.89 mg/L to 189.66. Otherwise, protozoa number in MEO treatment was lower compared to control (P<0.05). In conclusion, mix essential oil of eucalyptus and pine essential oil up to level 100μl/L could be used as feed additive to improve the fermentation of feed in the rumen.

Sampling and analysis of airborne ammonia in workplaces of China.

ObjectivesWith the increasing demand for the detection of occupational hazard factors in workplaces, the national standard determination method for ammonia (sampling with absorbing solution‐analysis with Nessler reagent spectrophotometry) in the air of workplace presents many drawbacks during application in China. This review summarized the improvement and the alternate methods of the current sampling and analysis procedures for ammonia, aiming to provide reference to establish an appropriate method for the determination of ammonia in workplace air.MethodsScientific publications in English and Chinese and the standard methods of the Deutsche Forschungsgemeinschaft (DFG) in Germany, the National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) in the United States, and Ministry of Health in China for airborne ammonia collection and analysis in the workplace were reviewed.ResultsThe measures to improve the current sampling and analysis procedures for ammonia in China were firstly summarized. For sampling, the decrease of absorbing solution concentration and the methanesulfonic acid solution as the alternate sampling solution were suggested. For analysis, the anti‐interference measures and the optimum reaction condition between ammonia and Nessler reagent were discussed. The alternate methods including sampling conducted using solid sorbent tubes and analysis performed by ion chromatography were then considered for the determination of ammonia.ConclusionsThe methods—sampling with acid‐treated solid sorbent tubes and analysis with ion chromatography—were more suitable for the determination of ammonia in workplace air. However, some details about ammonia sampling and analysis still need further investigation.

Simple colorimetric ammonium assay employing well microplate with gas pervaporation and diffusion for natural indicator immobilized paper sensor via smartphone detection

A simple and cost-effective analytical device based on gas pervaporation and diffusion method for determination of ammonia is proposed. The proposed device is consisted of a well microplate as a donor chamber and a natural indicator-immobilized paper (butterfly pea flower extract) as an acceptor sensor. This allows microliter-scale solution handling. The sample preparation step involved conversion of ammonium ion to ammonia using an alkaline solution, following by gas pervaporation and then diffusion of ammonia across a PTFE membrane into a natural indicator-immobilized paper. The colorimetric change on the paper then was detected by either a smart phone camera or naked eye for quantitative or semi-quantitative analysis, respectively. Under the optimal condition, a linear calibration with a range of 10–100 mg/L ammonium-nitrogen was obtained. The method has a detection limit (3σ) of 4 mg/L ammonium-nitrogen, n = 9. This proposed device was successfully applied for determination of ammonia in swine farming wastewater and chemical fertilizer samples. It could simultaneously perform triplicate run of 18 samples in 15 min (72 samples/hr). The proposed device with pervaporation and diffusion method offers on-site assay and green chemical analysis with relatively high throughput.

Synthesis of Micro-dumbbell Shaped rGO/ZnO Composite Rods and Its Application Towards as Electrochemical Sensor for the Simultaneous Determination of Ammonia and Formaldehyde Using Hexamine and Its Structural Analysis

The author describes a voltammetric sensor for the simultaneous determination of formaldehyde and ammonia using rGO/ZnO composite micro-dumbbell shaped rods. A facile hydrothermal technique was adopted to synthesize rGO/ZnO composite based micro-dumbbell shaped rods. The potential application based on obtained product has been employed as electrochemical sensor towards the detection of ammonia and formaldehyde using hexamine. For performing an electrochemical sensing application, glassy carbon electrode was modified with rGO/ZnO composite rods and analysed for the formation of multiple peaks thus emphasizing the detection of formaldehyde and ammonia using hexamine. Hexamine is toxic food preservative when it dissolutes in saline medium containing pH 7.4 emits ammonia and formaldehyde. The crystallinity property has been examined using X-ray diffraction technique revealing composite rods (rGO/ZnO) with 29.5 nm were lesser than ZnO NPs (38.33 nm). The surface morphology was investigated by scanning electron microscopy (SEM). In order to examine limit of detection (LOD) and sensitivity, cyclic voltammetry was carried out to determine the formaldehyde and ammonia. The voltammetric results revealed three different redox peaks with increased hexamine concentrations in which 0.4 V for formaldehyde, 0.13 V for ammonia and ~ 0.3 V for Zn2+ ions. The calibrated curve for ammonia with LOD and LOQ was found to be 0.1 µM and 0.9 µM and for formaldehyde with 0.023 µM and 0.07 µM respectively. Based on investigated results, the modified electrode was applied to the determination of ammonia and formaldehyde in urine samples (real-time analysis) and the results proved that the method is sensitive and can be an alternative to chromatographic and spectroscopic techniques.

Sequential Injection Analysis for Determination of Ammonia in Livestock Wastewater Using Acetoacetanilide as Hantzsch Reaction Reagent

Ammonia is a dangerous chemical compound in high concentrations. About 80-90% of ammonia total emissions come from animal fertilizer that produced from livestock, such as cattle farming. Based on the Minister of Environment Regulation Number 5 of 2014, the ammonia level in waste water standards for livestock activities is 25 mg/L. Some of the most common methods that used for determining ammonia are selective spectrophotometry and selective electrode, but the method has a disadvantage such as time consuming and low sensitivity. To overcome this problem, the aim of this study was to determine the dissolved ammonia levels in the liquid waste stream of cattle farms using the Sequential Injection Analysis (SIA) method by UV-Vis spectrophotometry at a wavelength of 307 nm based on the Hantzsch reaction using acetoacetanilide and formaldehyde reagents in acetate solution to form Dihydropyridine derivatives. The optimum condition of product formation occured in the order of reagents and sample segmentation of formaldehyde (R)-ammonia (S)-AAA(R) acetate with the volume ratio 75μL: 50μL: 100μL, respectively. The optimum conditions of the proposed method are 0.06 M of AAA concentration, 15% of formaldehyde concentration, reaction time of 40 s, and flow rate of 175 μL. High sensitivity (LOD:0.122 mg/L), fast analysis (175 s/sample) and high accuracy (recovery test > 94%), less and harmless waste could be attributed as advantages of the proposed SIA method.

A Hybrid Phase I-Phase II Toxicity Identification Evaluation (TIE) for the Simultaneous Characterization and Identification of Toxicants of Concern in Coastal and Estuarine Environments.

A sequential TIE procedure combining in a single framework Phase I manipulations and Phase II methods, including chemical analyses and complementary Phase I treatments, was proposed for characterization and identification of toxicants of concern in estuarine environments. Interstitial water was chosen as test matrix and embryo-larval development with the bivalve Crassostrea gigas as toxicity endpoint. TIE treatments included addition of Ulva rigida and elution through zeolite column for addressing effects due to ammonia, addition of EDTA and elution through a Cation-Exchange Solid-Phase Extraction column for characterize metals, and elution through two different type of polymers (XAD and DPA) with different affinity for polar and nonpolar organic pollutants. Chemical analyses concerned determination of ammonia and trace elements in the untreated sample and after manipulation intended to remove or modify bioavailability of ammonia and metals. The "hybrid" Phase I-Phase II TIE sequence proved to be a reliable and effective tool for the identification of main toxicant of concern in a highly toxic and contaminated interstitial water sample, also in presence of high concentration of potential confounding factors (ammonia). The addition of U. rigida was the more reliable treatment for the removal of ammonia, due to the concurrent release of particles and potentially toxic elements, such as Ba, Rb, and Tl by zeolite column, which may increase toxicity in the post-column sample. The combined use of polymers with different affinity for the various classes of organic pollutants was essential to identify the contribution of polar organic compounds to the observed toxicity.

Development of a micro-distillation microfluidic paper-based analytical device as a screening tool for total ammonia monitoring in freshwaters

An easy-to-use, portable 3D microfluidic paper-based analytical device (μPAD) for the determination of total ammonia (i.e., ammonia + ammonium) in freshwaters is described. It consists of two layers of paper patterned with hydrophilic circular zones, one impregnated with sodium hydroxide (sample zone) and another (detection zone) with an acid-base indicator (nitrazine yellow (NY) or bromothymol blue (BTB)), separated by a μ-distillation chamber. Ammonium ions present in the water sample are converted into ammonia gas by reaction with sodium hydroxide in the sample zone. Ammonia then diffuses through a headspace and reacts with an acid-base indicator in the detection zone, the reflectance of which can be related to the total ammonia concentration. The analytical signal at 7.8 mg L−1 offered by the μ-distillation chamber-based μPAD is more than double of that obtained using a gas-permeable membrane.The proposed μPAD is characterised by a limit of detection of 0.32 or 0.47 mg N L-1 and working concentration ranges of 0.5–3.0 mg N L-1 or 2.0–10 mg N L-1 when using NY or BTB indicators, respectively. This is the first μPAD whose working range covers almost the entire trigger value range (0.32–2.3 mg N L-1) for ammonia nitrogen in freshwater systems which makes it suitable as a field screening tool for ammonia in freshwaters. An inter- and intra-device repeatability of 7.6% and 9.0%, respectively, has been achieved for the NY-based μPAD (3 mg N L-1) and 13 and 2.5% (8 mg N L-1) for the BTB-based μPAD. The NY-based μPAD is stable under vacuum for at least 12 days at room temperature, and 56 days if stored in a freezer (≤−20 °C).

A smartphone-coalesced nanoprobe for high selective ammonia sensing based on the pH-responsive biomass carbon nanodots and headspace single drop microextraction.

Ammonia concentration together with pH values are important and closely linked indexes for aqueous systems. Rapid on-site determination of ammonia or pH is of great significance to environmental monitoring. In this work, a pH-switchable nanoprobe based on biomass carbon dots (CDs) is developed using a smartphone as a simple and handy instrument. The CDs demonstrate sensitive pH response in wide linear ranges of 6.1-13.6, and 2.0-13.6 with colorimetric and fluorescent channels, respectively. It is the pH-induced aggregation that governs the color and fluorescence switch. With the pH evolution caused by the dissolution of ammonia, the smartphone-integrated nanoprobe is applied to ammonia detection with a broad range of 0.5-300 mM. Moreover, the headspace single drop microextraction strategy can concentrate ammonia from matrix, offering a remarkably high selectivity for ammonia determination. Finally, the practical applications of this method for ammonia analysis obtained satisfactory results.

Improvement of Determination Method of Ammonia in Indoor Air and Analysis of Monitoring Results

This paper mainly compares the determination of ammonia in indoor air by hypobromite oxidation method and salicylic acid spectrophotometry, and selects higher precision, higher sensitivity, larger linear range and more stable results. The reproducible salicylic acid method is improved. In this way, the salicylic acid method is more convenient, time-saving and easy to operate, and is advantageous for the application of the method in a wider range.

Purge-and-trap Determination of Ammonia in Water Samples Using Needle-type Extraction Coupled with Gas Chromatography-Barrier Discharge Ionization Detection.

This manuscript describes the determination of ammonia (NH3) in aqueous samples by purge-and-trap extraction using a needle-type extraction device with gas chromatography-barrier discharge ionization detector (GC-BID). NH3 was purged from the aqueous samples in basic conditions and then salted out with sodium chloride. Purged ammonia was trapped onto non-volatile carboxylic acid-coated macroporous terephthalic acid particles, which were contained within the needle-type extraction device. The analyte (NH3) was thermally desorbed by heating the extraction needle in the GC injection port, and detected by BID. After the optimization of both purge and extraction conditions, the linearity and sensitivity of the proposed method were evaluated. The limit of detection was found to be 2.0 mg L-1 at a headspace sampling volume of 100 mL. The method applicability was confirmed by the determination of spiked NH3 in tap water and river water samples.

Determination of Highest Dose of Ammonia without Effect at Work Environment through the Expression of Interleukin-2 Cell in Rattus Novergicus.

BACKGROUND:For determining the threshold limit value firstly determined the highest dose of ammonia without effect (NOAEL). However, research on the determination of NOAEL ammonia didn’t conduct in Indonesia.AIM:The aim of this study to determine the value of the highest dose of ammonia without effect (No Observed Adverse Effect Level/NOAEL) through interleukin-2 (IL-2) expression on white mice.METHODS:This study used experimental laboratory research with post-test only control group design using white mice as experimental subjects. The treatment group divided into 6 groups (a group of controls and five groups with different ammonia exposure through inhalation). The trend curve of Remmele Scale Index (IRS) and histopathologic analysis could be used for determining NOAEL.RESULT:The location of the highest dose of ammonia without any effect (NOAEL) of white mice was in the second group, with 0.0103 mg/kg body weight dose. Analysis of statistical tests Kruskal Wallis stated there was no significant difference in interleukin-2 expression between the control with ammonia exposed group with a significance of p (0.747) > α (0.05).CONCLUSION:There is no difference between some interleukin-2 expression in the lymphocyte cell lung white mice group exposed to ammonia and control group. The highest dose of ammonia without any effect (NOAEL) on white mice was 0.0103 mg/kg body weight.

Adherence to Recommended Inpatient Hepatic Encephalopathy Workup.

Hepatic encephalopathy (HE) is characterized by altered sensorium and is the most common indication for hospitalization among patients with cirrhosis. Liver societal guidelines for inpatient HE revolve around identification of potential precipitants. In this retrospective study, we aimed to determine adherence to societal guidelines for evaluation of HE in 78 inpatients. The adherence rate to societal recommended guidelines for workup of HE was low, with only 17 (22%) patients having complete diagnostic workup within 24 hours of admission. Notably, 23 (30%) patients were not subjected to blood culture analysis, 16 (21%) were missing urinalysis, and 15 (20%) were missing chest radiograph. In patients with ascites (N = 34), 26 (77%) did not have a diagnostic paracentes is to exclude spontaneous bacterial peritonitis. In contrast, serum ammonia determination, a laboratory test not endorsed by societal guidelines for workup of HE, was ordered in 74 (95%) patients. These findings underscore the limited adherence to societal guidelines in hospitalized patients with HE.

Direct tracing of NH3 and N2O emissions associated with urea fertilization approaches, using static incubation cells

Nitrogen fertilization contributes significantly to crop production globally. However, low efficiency application management approaches lead to substantial N losses of which ammonia and nitrous oxide are known as environmental threats. Urea, the largest N fertilization source globally, is associated with high ammonia losses. A large variety of application modes are practiced under different environmental conditions worldwide. Yet, the complexity of N-processes in different soils, under changing agro-environmental conditions, challenges the evaluation of fertilization approaches efficiency in reducing N-gaseous losses. In this research a simply designed static incubation cell was connected to a Long-Path gas cell and a Fourier Transform IR spectrometer (LP-FTIR), allowing online determination of ammonia and nitrous oxide emissions in parallel to tracking mineral N-dynamics in soil samples. The static chamber was used to evaluate different application approaches of urea (i.e., incorporation or surface application with or without wetting) in a Sandy Loam and to compare surface applied regular urea vs. urea amended with the urease inhibitors NPPT+NBPT [N-(n-butyl) thiophosphoric triamide and N-(n-propyl) thiophosphoric triamide, respectively] in four different representative soils. Ammonia emissions peaked few days after application, where highest losses were observed for surface application mode. Highest emissions, up to 5% (w/w) of applied Urea-N, were obtained with the lighter and more basic soils (Sandy Loam and Loess; pH > 7.9). Nitrous oxide emissions showed a lag period of ~1 week and were higher under lower urea application rates, and when nitrification was faster (~1–1.3% (w/w) of applied N). Urease inhibitors significantly reduced ammonia losses in all tested soils and particularly in the Sandy Loam and Loess. Their effect on nitrous oxide losses were observed with the Sandy Loam and particularly after 2 weeks. The static system may underestimate realistic ammonia losses, but it offers a rather simply operated system, providing information about N-gaseous losses for improving N-fertilization management.

Comparison of Two Colorimetric Methods for the Determination of Trace Ammonia in Water

Comparison of Two Colorimetric Methods for the Determination of Trace Ammonia in Water

Development of a low cost gas diffusion device for ammonia detection in the vitreous humor and its preliminary application for estimation of the time since death

A simple and low cost analytical device is described for the determination of ammonium in the vitreous humor suitable for inferring the post mortem interval in forensic cases. The device is based on ammonia formation from ammonium ion by means of NaOH addition to the vitreous humor sample and its detection with a pH chemical indicator in the gas phase above the vitreous humor sample. From the gas phase, ammonia diffuses through a polymeric membrane and it is trapped and detected with a droplet of pH indicator thymol blue. The color change of the droplet is measured using a smartphone camera. Under optimal conditions, the device showed a limit of detection of 0.2mM, with between days precision of ≤ 15% expressed as relative standard deviation, and an accuracy between days from 88.3% to 114.5%. This homemade gas diffusion analytical device was successfully used for the determination of ammonia in vitreous humor samples from forensic autopsies. The results obtained with the proposed method, although for a limited number, showed a close correlation with the data obtained with an instrumental analysis based on capillary electrophoresis. Moreover a significant correlation was also found between the results of the present method and the time elapsed since death by a simple evaluation of the color intensity. In conclusion, this preliminary study showed that the proposed device, after adequate validation, could be a promising tool for a presumptive estimation of the time since death directly at the crime scene.