Effect Of Ammonium Acetate Research Articles

Effect of ammonium acetate on alcohol fermentation in cassava-alcohol fermentation process

The cassava-alcohol fermentation process employing cassava requires nitrogen source to maximize yields by a commercial strain of S. cerevisiae TG1348. In this study, a factorial experimental design was used to assess a suitable nitrogen source for growth and fermentative performance of S. cerevisiae in cassava-ethanol fermentation. The alcohol fermentation time was about 39 h for urea and ammonium acetate, which was 48 h for ammonium chloride and ammonium sulphate. The fermentation time was reduced by 19 % when using urea and ammonium acetate as nitrogen source. Ammonium acetate leaded to the highest alcohol yield, which was 4% higher than for ammonium sulphate. In addition, byproduct formation differed obviously between the nitrogen sources. The glycerol yields were similar for urea, ammonium sulphate and ammonium chloride but were 24 % lower for ammonium acetate. However, glycerol yield for ammonium carbonate was higher than for other nitrogen sources. Clearly, in batch cultures the ammonium acetate not only increased ethanol generation, but also decreased glycerol generation. In order to understand why ammonium acetate promotes alcohol fermentation, acetic acid was added to different nitrogen sources. The weight loss effect of ammonium sulphate adding acetic acid and ammonium acetate as nitrogen source was the same. The fermentation time was shortened by adding acetic acid. And pH was increased by addition of acetic acid when ammonium sulfate and urea were used as nitrogen sources. The results showed that the acetate root plays an important role in ammonium acetate. The results of this study could facilitate the development of new strategies to control fermentation performance.

Unravelling the effects of mobile phase additives in supercritical fluid chromatography—Part II: Adsorption on the stationary phase

The mobile phases employed in current practice of supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). In the first part of this series, the effects of mobile phase additives on the polarity and apparent pH of the mobile phase were explored. In the present paper, we examine the effects pertaining to adsorption of additives on the stationary phase. Ammonium acetate was selected as a representative case, because it is often employed in current practice. To favour its solubility and further improve chromatographic quality, a small portion of water is also advocated. First, the equilibration time is observed to be largely increased in the presence of an additive, especially when mobile phase compositions containing only low proportions of methanol co-solvent are employed. Secondly, the effects of ammonium acetate are more thoroughly assessed with a modified version of the solvation parameter model (five Abraham descriptors and two descriptors to take account of positive and negative charges on ionizable species). On a hybrid silica stationary phase (ACQUITY UPC2 BEH), the effects of increasing concentration of ammonium acetate (0–25 mM in the methanol co-solvent) are investigated. The retention of acidic species is the most strongly affected, with a continuous retention increase when additive concentration increases. The retention of basic and neutral species is also moderately affected. Then thirty-two stationary phases based on sub-2 μm totally porous particles or sub-3 μm superficially porous particles are characterized with and without 20 mM ammonium acetate and 2% water in the methanol co-solvent. The effects of adsorbed additive on the interaction capabilities are discussed. Finally, the interest of introducing the additive in the dilution solvent, a method that was sometimes recommended to simplify the workflow, is also discussed with a model basic compound.

Detection of multiclass explosives and related compounds in soil and water by liquid chromatography-dielectric barrier discharge ionization-mass spectrometry.

In this work, the multiclass detection of explosives and related compounds has been studied by liquid chromatography-high-resolution mass spectrometry by means of a time-of-flight mass spectrometer (TOFMS) operated in the negative ion mode, using dielectric barrier discharge ionization (DBDI). Reversed-phase high-performance liquid chromatography (HPLC) separation was performed using water-methanol mobile phase without any modifier, although the effect of ammonium acetate was studied. DBD plasma was generated by applying a square wave voltage of 2.5kV to a 100-mLmin-1 He flow. The DBDI probe was adjusted to fit the commercial API source housing so that the HPLC eluent was nebulized and vaporized in the same manner as for atmospheric-pressure chemical ionization (APCI). The ionization process was affected by the temperature of the two nitrogen streams used to vaporize the solvent and the analytes, particularly for RDX and HMX, which are thermolabile compounds. The best approach in terms of sensitivity for all the studied compounds was the use of a gradient of temperatures in the ionization source, starting at 225/200°C (vaporizer/drying gas temp) for nitramines and ending at 350/325°C for nitroaromatic compounds. High-resolution full-scan spectra of individual selected compounds were recorded by LC-DBDI-TOFMS, and the results were compared to LC-APCI-TOFMS. A better sensitivity (slope of calibration curve) was obtained by DBDI for more than 70% of the studied compounds in both wastewater and soil extracts. Graphical abstract ᅟ.

Effect of Ammonium Acetate on the Properties of Chemical Bath Deposited CdS Films

ABSTRACTThis investigation is a comprehensive study of the effect of ammonium acetate on the electrical, optical, morphology and microstructure of CdS thin films grown by Chemical Bath Deposition method (CBD). Two sets of CdS thin films (A and B) were deposited on glass substrates at 60°C for 60 min. The films were deposited using chemical bath solution that consists of cadmium acetate, ammonium hydroxide, and thiourea. However, ammonium acetate was added into the chemical bath used to deposit set (B), where ammonium acetate was eliminated from bath solution used to deposit set (A). The films’ morphology was examined by Field Emission Scanning Electron Microscopy (FE-SEM), whereas, the chemical composition was investigated by Electron Probe Micro-Analyzer (EPMA). The X-Ray Diffraction (XRD) θ/2θ technique was applied to study the structure of the films. Atomic Force Microscopy (AFM) was used to measure the average surface roughness of the films, and Dektak Profilometer was used to determine the CdS films thickness. The optical and electrical properties for the films were determined using UV-Vis-NIR Spectrometer, and the Hall Effect technique, respectively. The highest carrier mobility was obtained for the films deposited in an ammonium acetate free bath. However, both films were polycrystalline with hexagonal structure exhibiting a tendency toward <002> texture, that increase with increasing the pH value of the chemical bath.

Convenient MCRs Synthesis of Trifluoromethylated Pyrano[4,3-b]pyrans and Their Further Transformation

Ethyl 2-hydroxy-7-methyl-5-oxo-4-aryl-2-(trifluoromethyl)-3,4-dihydro-2 H ,5 H -pyrano[4,3- b ]pyran-3-carboxylate derivatives were synthesized via a one-pot three-component reaction (MCR) promoted by ammonium acetate. The effect of ammonium acetate and the solvent on the reaction efficiency was investigated. Furthermore, treatment of the resultant products with thionyl chloride/pyridine in chloroform gave the corresponding dehydrated products ethyl 4-aryl-7-methyl-5-oxo-2-(trifluoromethyl)-4 H ,5 H -pyrano[4,3- b ]pyran-3-carboxylates and the unexpected defluorinated products ethyl 3-aryl-6-methyl-4-oxo-4 H -furo[3,2- c ]pyran-2-carboxylates. The novel products are highly important for the synthesis of related fluorinated fused heterocyclic compounds.

Investigations on the solubility, growth, structural, optical, mechanical, dielectric and SHG behaviour of ammonium acetate doped ammonium dihydrogen phosphate crystals

Ammonium acetate doped ammonium dihydrogen phosphate single crystals have been grown by slow cooling along with bidirectional seed rotation method. Effects of ammonium acetate on the solubility, growth rate, structural, optical, mechanical, dielectric properties, crystalline perfection and second harmonic generation efficiency of the crystals have been investigated. The high-resolution X-ray diffraction study shows that the crystalline perfection of the doped crystal is good. Fourier transform infrared studies confirm the functional groups of the crystals. It is seen from UV–vis studies that the optical transparency is increased much by the dopant. Vickers hardness measurements reveal the mechanical stability of the crystals. Low dielectric losses were observed from the dielectric measurements for the doped ADP crystals at higher frequencies. The relative SHG efficiency measurements revealed that the dopant has enhanced the efficiency.

Increase of Ammonia Pool in the Gastrointestinal Tract of Rats Potentiates Acute Toxicity of Cyclophosphamide

For evaluation of the impact of changes of ammonia pool in the gastrointestinal tract on acute toxicity of cyclophosphamide, the dynamics of blood levels of ammonia and urea of rats was studied after intraperitoneal injection of cyclophosphamide (600 mg/kg) and clinical manifestations of intoxication and lifespan of rate were studied after cyclophosphamide injections in doses of 200, 600, 1000, and 1400 mg/kg alone or in combination with ammonium acetate. Ammonium acetate stimulated the hyperammoniemic and uremic effects of cyclophosphamide. Combined effects of the toxicants were associated with symptoms characteristic of acute poisoning with ammonium salts; these symptoms were not observed under the effect of ammonium acetate alone. Ammonium acetate stimulated the lethal effect of cyclophosphamide injected in doses of 200, 600, 1000, or 1400 mg/kg: the mean lifespan of rats decreased by 1.5, 2.1, 2.8, or 6.1 times, respectively. These data indicate that ammonia redistribution from the gastrointestinal tract into circulating blood is one of the mechanisms of thanatogenesis in acute cyclophosphamide intoxication.

A comparative assessment of the response of three fruit fly species (Diptera: Tephritidae) to a spinosad-based bait: effect of ammonium acetate, female age, and protein hunger

Ammonia-releasing substances are known to play an important role in fruit fly (Diptera: Tephritidae) attraction to food sources, and this information has been exploited for the development of effective synthetic food-based lures and insecticidal baits. In field studies conducted in Hawaii, we examined the behavioural response of wild female oriental fruit fly (Bactrocera dorsalis (Hendel)), melon fly (B. cucurbitae (Coquillett)), and Mediterranean fruit fly (Ceratitis capitata (Wiedemann)) to spinosad-based GF-120 NF Naturalyte Fruit Fly Bait(©) formulated to contain either 0, 1 or 2% ammonium acetate. Use of visually-attractive yellow bait stations for bait application in the field allowed for proper comparisons among bait formulations. Field cage tests were also conducted to investigate, using a comparative behavioural approach, the effects of female age and protein starvation on the subsequent response of F1 generation B. cucurbitae and B. dorsalis to the same three bait formulations that were evaluated in the field. Our field results indicate a significant positive effect of the presence, regardless of amount, of AA in GF-120 for B. dorsalis and B. cucurbitae. For C. capitata, there was a significant positive linear relationship between the relative amounts of AA in bait and female response. GF-120 with no AA was significantly more attractive to female C. capitata, but not to female B. dorsalis or B. cucurbitae, than the control treatment. Our field cage results indicate that the effects of varying amounts of AA present in GF-120 can be modulated by the physiological stage of the female flies and that the response of female B. cucurbitae to GF-120 was consistently greater than that of B. dorsalis over the various ages and levels of protein starvation regimes evaluated. Results are discussed in light of their applications for effective fruit fly suppression.

Effect of increasing concentration of ammonium acetate as an additive in supercritical fluid chromatography using CO 2–methanol mobile phase

The effects of increasing concentrations of ammonium acetate additive in supercritical fluid chromatography were studied on silica, 2-ethyl-pyridine and endcapped 2-ethyl-pyridine stationary phases. The study involved the addition of increasing concentrations of the ammonium acetate either in the mobile phase modifier (methanol) or in the sample solvent. The effects of ammonium acetate on retention and peak shape of the analytes were evaluated. Compounds that exhibited satisfactory chromatographic behaviour in the absence of the additive were virtually unaffected by its presence in the mobile phase or sample solvent. Nevertheless, compounds that exhibited late elution and strongly tailing peak shapes when pure methanol was used showed dramatically improved chromatographic behaviour in the presence of the additive. Shorter retention was observed not only when the modifier was introduced in the mobile phase but also when it was in the sample solvent.

Synthesis of hydrated CeO2 nanowires and nanoneedles

Hydrated CeO2 nanowires as thin as 5 nm in diameter and nanoneedles with various aspect ratios were obtained via a chemical precipitation technique in the presence of ammonium acetate. It was possible to control the particle size, shape and agglomeration by tuning the ammonium acetate concentration in the experimental solutions. The effect of ammonium acetate on the particle morphological parameters is discussed and a possible mechanism is suggested.

Preparation of aluminum oxide particles using ammonium acetate as precipitating agent

The effect of ammonium acetate on the preparation of alumina particles as precipitating agent was investigated. Alumina particles were prepared by precipitation of aqueous aluminum chloride solution by using ammonium acetate and ammonium hydroxide. The thermal behaviors, morphologies and surface area were studied for alumina particles formed by ammonium acetate and compared with those of particles formed by ammonium hydroxide. The particles formed by ammonium acetate showed a narrower size distribution, spherical shape, larger surface area and lower crystallinity. These results were explained based on the chelating effects of acetate ions.

Investigations of Particle Characteristics and Carrier Effects on Particle Beam LC-MS

We investigated the characteristics of the particles resulting from a thermospray nebulizer and two different desolvation systems for particle beam liquid chromatograpgy-mass spectrometry (PB-LC-MS). The particle size distributions and shapes/morphologies were characterized using a scanning mobility particle sizer (SMPS) and high resolution transmission electron microscopes (HRTEM), respectively. The carrier effects of ammonium acetate were evaluated with these particle characteristics and the PB-LC-ITMS responses. The addition of ammonim acetate changed the particle size distributions and shapes/morphologies, and also significantly increased the analyte transmission efficiency in both the SMPS and the PB LC-ITMS. However, ammonium acetate did not cause increases in paricle sizes and particle size decreases were even observed in some cases. The observed particle shapes and morphologies were different for caffeine and 3,3′-dimethoxybenzidine, and also depended on the desolvation methods. These results were interpreted to be due to the combined carrier effects of fragmenting large aerosols, increasing analyte solubility, and neutralizing the charged particles. The fragmentation of large aerosol particles via the addition of the semivolatile carrier was also hypothesized as a major process reducing the gravitational loss of aerosols and increasing the analyte transport efficiency. In the other set of experiments based on UV absorption, the mass balance of caffeine was evaluated. Both the SMPS and the mass balance data suggested that the porous membrane desolvation system could discriminate the small particles which, at least in part, resulted in the poor analyte transmission efficiency and nonlinear calibration behaviors of PB LC-MS.

Reversed-Phase Ion-Pair Liquid Chromatography of a Pharmaceutical Compound and Its Photolytically Transformed Isomer

Reversed-phase HPLC is usually the method of choice for compounds that dissolve in water/organic mixtures, even for samples that contain ionizable compounds. However, reversed-phase ion-pair chromatography (RP-IPC) is often a useful alternative for such samples, particularly if the components are highly basic or acidic. With this technique an aqueous/organic mobile phase is used along with a buffer and an ion-pairing reagent to provide more retention and higher selectivity than are afforded by the column and organic solvents alone. The retention effects of ammonium acetate, sodium acetate, potassium phosphate, and triethylamine (TEA) on a pharmaceutical compound (SK&F 108566) and its stereoisomer (SB 206328) were studied. Evidence indicated that SK&F 108566 and SB 206328 exhibited ion-pair formation with simple buffer systems and the ion-pair occurred in the mobile phase prior to the complex binding rapidly to the stationary phase. As a result, buffer systems such as sodium acetate, ammonium acetate, and potassium phosphate could be used as ion-pairing reagents. Thus, a simple HPLC system which not only provided better buffer capability but also improved selectivity through ion-pair interactions could be utilized for ionic compounds separation. One important result to emerge from this study is the potential for isocratic, multidimensional HPLC separations when reversed-phase columns are coupled and used with the appropriate buffer solutions.

The benzodiazepine antagonist CGS 8216 prevents hyperammonemia-induced somatostatin receptor reduction in the brain.

Previous results from our group showed that hyperammonemia decreases the number of somatostatin (SS) receptors and that benzodiazepine receptors might regulate the number of SS receptors in rat brain. These findings together with the supersensitivity of benzodiazepine receptors in the hyperammonemic rat brain suggest that benzodiazepine receptors might mediate the effect of hyperammonemia on SS receptors. To assess this hypothesis we tested whether 2-phenylpyrazolo[3,4-c]-quinolin-3(5H)-one (CGS 8216), a benzodiazepine antagonist, prevented the effect of ammonium acetate on rat brain SS receptors. Administration of ammonium acetate (5 mmol/kg, i.p.) for 7 days did not affect the levels of somatostatin-like immunoreactivity but decreased the number of SS receptors in synaptosomes from the frontoparietal cortex and hippocampus without affecting their apparent affinity. This decrease could be blocked by the concomitant administration of CGS 8216 (10 mg/kg, i.p.). The benzodiazepine antagonist alone had no observable effect on the somatostatinergic system. These results suggested that the effect of hyperammonemia on SS receptors could be mediated, at least in part, through the benzodiazepine receptors.

Effect of ammonium acetate on the somatostatinergic system in the rat frontoparietal cortex

Short (90 min)-, mid (5 days)-, and long-term (15 days) ammonium acetate (5 mmol/kg IP) administration decreased the number of specific [ 125I][Tyr 11]somatostatin receptors in synaptosomes from the frontoparietal cortex without changing the affinity constant. Administration of ammonium acetate did no affect the levels of somatostatin-like immunoreactivity in the frontoparietal cortex. The administration of a single dose of N- carbamyl - l-glutamate (1 mmol/kg) plus l-arginine (1 mmol/kg) 1 h before the last administration of ammonium acetate totally blocked the inhibitory effects of the latter on somatostatin receptor number in the frontoparietal cortex synaptosomes. N- Carbamyl - l-glutamate plus l-arginine alone had no observable effect on the somatostatinergic system. The decrease in the number of somatostain receptors induced by ammonium acetate might reflect decreased target cell sensitivity to somatostatin, a phenomenon that could contribute to the depressed neuronal excitability induced by ammonia in the rat frontoparietal cortex.

Differential Pulse Polarographic Analysis of Powders and Explosives

AbstractThis investigation demonstrates how mixtures of glycerol trinitrate, diethyleneglycol dinitrate, 2,4‐dinitrotoluene, 2,4,6‐trinitrotoluene, nitroguanidine, dibutyl phthalate, diethyl phthalate, cyclotrimethylene trinitramine (hexogen) and cyclotetramethylene tetranitramine (octogen) in powders and explosives can be analysed by differential pulse polarography. The analysis of, for example, glycerol trinitrate, 2,4‐dinitrotoluene and 2.4,6‐trinitrotoluene in powder is made as a three‐component system with overlapping polarograrns, while the analysis of dibutyl phthalate, nitroguanidine and glycerol trinitrate in powder is made as three independent single component systems.The polarographic reduction of organic compounds is effected both by the composition of the solvent and its pH value. By careful choice of the experimental conditions it is often possible to obtain sufficiently differing forms of differential pulse polarograms for the various compounds, which can be exploited for analytical purposes. Various water! methanol solutions have been studied to find the mixtures that give the greatest differences in the polarograms. The effect of ammonium acetate and tetramethyl ammoniumbromide as electrolyte has been studied.

Effects of ammonium salts on synaptic transmission to hippocampal CA1 and CA3 pyramidal cells in vivo

The effects of ammonium acetate or chloride, perfused through the lateral ventricle, were studied on the hippocampal formation of the rat. During perfusion with ammonia, the population spikes, evoked by stimuli delivered to the fimbria, were first increased and then reduced. On the other hand, the late positive wave gradually decreased throughout the application of ammonia. The inhibition, studied by the paired-pulse test, was found to be reduced when the population spike was transiently enhanced, indicating that disinhibition could be responsible for the enhancement of synaptically evoked responses. Neither antidromically evoked population spikes nor the typical effects of iontophoretically applied glutamate, aspartate or γ-aminobutyrate were changed by ammonia. These findings can be accounted for by a single action of ammonia, a depression of excitatory synaptic transmission, the excitatory synapses on inhibitory interneurons being more readily depressed than those on the pyramidal cells. Both effects, early hyperexcitability and late depression, are probably due to a reduction in the release of the excitatory neurotransmitter, glutamate and/or aspartate. We tentatively suggest that these mechanisms are responsible for some of the symptoms observed during the development of hyperammonemic encephalopathies.

The effect of acute ammonia intoxication upon the brain energy state in rats pretreated with L-methionine D-L-sulphoximine.

The effects of ammonium acetate upon the brain energy state in MSO-pretreated animals were evaluated in lightly anesthetized normocapnic rats. Ammonia intoxication was associated with increased lactate contents, raised lactate/pyruvate ratios. With high ammonia contents inconsistent changes in the energy state occurred in both supratentorial and infratentorial structures, indicating a labile energy homeostasis. It was concluded that inhibition of glutamine synthetase is of minor importance for maintaining energy balance and probably could not account for the protective effect of MSO against acute ammonia intoxication.

The effect of ammonium acetate on the yield and composition of milk from heifers

1. Two experiments are described in which the effects of ammonium acetate on the yield and composition of the milk from heifers given (1) a fat-depressing diet consisting mainly of cereals or (2) a normal diet of silage and sugar beet pulp for maintenance and rationed concentrates according to yield.2. In the first experiment acetate increased the content of butterfat in the milk from 2·76 to 3·12. This difference was almost significant (P < 0·1). There was no significant effect of acetate on the total solids content of the milk.3. In the second experiment acetate very slightly depressed the total solids and the butterfat content of the milk.4. In Experiment 1 there was no significant difference between treatments i n the pH of rumen liquor, or in its concentration of total steam volatile fatty acids, but the proportions of acetic and isobutyric acids were higher on the acetate treatment.5. In Experiment 2 there were no differences in the relative proportions of the fatty acids although the total steam volatile fatty acid concentration was higher on the acetate treatment.