نتایج جستجو برای: ammonium hydroxide
تعداد نتایج: 39681 فیلتر نتایج به سال:
Gas chromatographic/thin-layer chromatographic analysis of acetylated codeine and morphine in urine.
This procedure positively identifies codeine and morphine in urine. Urine samples are hydrolyzed and extracted with organic solvent, and the extracts are evaporated and acetylated. The presence of codeine and morphine is ascertained by gas chromatography (3% OV-25 and 3% Poly-A 103 columns) and confirmed by thin-layer chromatography (system: ethyl acetate/acetone/concd ammonium hydroxide, 100/1...
Anion exchange membranes (AEM) based on polyphenylene oxide (PPO) suffered quaternary-ammonium-cation-site degradation in alkaline environments. Surprisingly, the degradation rate was considerably faster in the presence of molecular oxygen. We postulated that the AEM cation-site catalyzes the reduction of dioxygen by hydroxide ions to yield the superoxide anion radical and the highly reactive h...
Article info: Received: 25 October 2012 Accepted: 21 December 2012 ABSTRACT A rapid and accurate TLC-densitometry method for qualitative and quantitative determination of protopine has been developed. The best separation was achieved using a mobile phase chloroform – ethyl acetate – methanol – ammonium hydroxide (80:80:40:0.05, v/v/v/v). The results obtained by this method (CV% 3.4) corresponde...
This paper was intended as a comparative study between the microstructural features of two water-ferrofluids intended for biological applications. In both cases the ferrophase was prepared by auto-catalytic reaction between ferrous and ferric salts resulted in magnetite and some maghemite precipitates. The difference is given by the stabilizer molecule: tetramethyl ammonium hydroxide and, respe...
A novel surface micromachining process is reported for aluminum nitride (AlN) thin films to fabricate piezoelectric unimorph suspension devices for micro actuator applications. Wet anisotropic etching of AlN thin film is used with a Cr metal mask layer in the microfabrication process. Tetra methyl ammonium hydroxide (TMAH) of 25 wt.% solution is used as an etching solution for the AlN thin film...
Carbonylruthenium tetrakis(pentafluorophenyl)porphyrin Ru(TPFPP)(CO) was utilized for the aerobic oxidation of alcohols. The in situ activation of the catalyst with mCPBA provided a species capable of catalyzing the oxidation of alcohols with molecular oxygen. The choice of solvent and additive was crucial to obtaining high activity and selectivity. Secondary aromatic alcohols were oxidized in ...
The adsorption characteristics of As(V) and As(III) on titanium dioxide loaded Amberlite XAD-7 resin have been studied. The resin was prepared by impregnation of Ti(OC2H5)4 followed by hydrolysis with ammonium hydroxide. Batch adsorption experiments were carried out as a function of the pH, shaking time and the concentration of As(V) and As(III) ions. The resin showed a strong adsorption for As...
Polypropylene composites with different filler contents were prepared by creating a masterbatch containing 3 wt%. filler. A variety of silanol groups were used to synthetized three compounds in different media trough a sol-gel process with acetic acid, formic acid and ammonium hydroxide as catalysts. Besides, four different nanotubular fillers were also used to analyze their behavior and compar...
Tuberculosis continues to cast a huge impact on humanity with its high incidence and mortality, especially in developing countries. For tuberculosis case detection, microscopy continues to be indispensible, given its low cost, rapidity, simplicity of procedure and high specificity. Modifications have attempted to improve the sensitivity of microscopy which include: concentration methods such as...
The title compound, C(12)H(15)NO, a degradation product of molindone hydro-chloride, was prepared by the reaction of molindone with methyl iodide and subsequent reaction of the resulting quaternary ammonium salt with 2N aqueous sodium hydroxide. The newly formed double bond is exocyclic in nature and the carbonyl group is conjugated with the π-electrons of the pyrrole ring. The six-membered rin...
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