Eluents ammonium hydroxide

Olefins, sultones, alkanes, and alkenesulfonates may be separated by liquid chromatography on silica gel using hexane, trichloromethane-hexane, ethanol-dime thy lcarbonate, and ethanol-ammonium hydroxide as the eluents. Pueschel and Prescher [110] achieved the separation of alkene-1,4-sultone and alkene-1,3-sultone from each other and from other sulfonic acid esters in AOS by thin-layer chromatography on silica gel G with 4 1 diethylcarbonate-ligroine as the... 

Eluent A mixture of toluene, isopropyl alcohol, and ammonium hydroxide (70 29 1), in a nonequilibrated chamber. 

Musumarra et al. [43] identified miconazole and other drugs by principal components analysis of standardized thin-layer chromatographic data in four eluent systems. The eluents, ethylacetate methanol 30% ammonium hydroxide (85 10 15), cyclohexane-toluene-diethylamine (65 25 10), ethylacetate chloroform (50 50), and acetone with the plates dipped in potassium hydroxide solution, provided a two-component model that accounts for 73% of the total variance. The scores plot allowed the restriction of the range of inquiry to a few candidates. This result is of great practical significance in analytical toxicology, especially when account is taken of the cost, the time, the analytical instrumentation and the simplicity of the calculations required by the method. 

A number of minor components present in commercial neomycin have been separated by column chromatography on a carboxylic cation-exchange resin, Amberlite CG-50 99. The components were eluted from the resin with ammonium hydroxide solution. T.L.C. of the eluent fractions showed the presence of two previously unreported impurities which were then isolated on Dowex 1X2 and tentatively identified using NMR and mass spectrometry. 

Figure 4.18 Analysis of anions in water using ion-pair liquid chromatography. Column, octadecyl-bonded silica gel, 15 cm x 4.6 mm i.d. eluent, 2 mM tetrabutyl-ammonium hydroxide (pH 5.3) in 3% acetonitrile-water flow rate, 1 ml min- detection, UV200 nm. Peaks 1, Br 2, N03 and3,1. ...

The use of formic acid, acetic acid and ammonium formate rather than triflu-oroacetic acid can substantially increase sensitivity because their proton affinities are lower than that of the TFA anion - though TFA is often used in the analysis of peptides. It is always advisable to keep the level of acid additives to less than 0.1% v/v, and preferably 0.03-0.05% v/v, in the final eluent. Triethylamine or ammonium hydroxide can be used successfully in negative mode because they promote deprotonation of acidic species. 

Elemental composition Cr 52.00%, 0 48.00%. The compound may he identified from its dark red color. Other color phases are noted above. Chromium may he measured in the aqueous phase hy AA, ICP or x-ray techniques, or in the solid phase hy x-ray methods. Hexavalent chromium (Cr6+) may he analyzed hy ion chromatography. For this, the aqueous sample is adjusted to pH 9 to 9.5 with a concentrated buffer (ammonium sulfate and ammonium hydroxide mixture) and mixed into the eluent stream of the buffer. Cr " is separated from Cr + on a column, and derivatized with an azide dye as a colored product measured at 530 nm, which is identified from its retention time. (APHA, AWWA, and WEF. 1999. Standard Methods for The Examination of Water and Wastewater, 20th ed., Washington, DC American Public Health Association.)... 

To a solution of previously dried l-[[2-carboxy-3-(2-dimethylaminoethyl)-5-indolyl]methanesulphonyl]-pyrrolidine (1.6 g 0.0442 moles) in anhydrous quinoline (75 ml) and under atmosphere of nitrogen, cuprous oxide (160 mg 0.0011 moles) was added. The reaction mixture was heated to 190°C for 15 minutes, stirred to room temperature, poured into a mixture of 1 N hydrochloric acid (150 ml) and ethyl acetate (50 ml), shaken and decanted. The aqueous solution was washed several times with ethyl acetate, then solid sodium bicarbonate was added until pH = 7.8, and washed with n-hexane to eliminate the quinoline. The aqueous solution was made alkaline with solid potassium carbonate and extracted with ethyl acetate. The organic solution was dried (Na2S04), the solvent removed under reduced pressure when a dark oil was obtained (1.3 g yield 92%). This product was purified by column chromatography with silica gel and methylene chloride ethanol ammonium hydroxide (60 8 1) as eluent and a white foam (0.8 g) of l-[[3-(2-dimethylaminoethyl)-5-indolyl]methanesulphonyl]-pyrrolidine was obtained. To a solution of the above product (0.8 g) in acetone (30 ml), a few drops of hydrogen chloride saturated dioxan solution, were added. The precipitated solid was collected by filtration, washed with acetone and dried to give l-[(3-(2-(dimethylamino)ethyl)-5-indolyl)methanesulphonyl]-pyrrolidine hydrochloride (0.75 g). Melting point 218°-220°C. 

The eluents most commonly used in peptide purification by reversed phase HPLC are water and acetonitrile. These are often buffered with trifluoroacetic acid (0.1% v/v, TFA), ammonium acetate (0.05-0.1 mol/dm3 at pH 4-8) or phosphate (0.05-0.1 mol/dm3 sodium or potassium salt at pH 2-8). In addition, polymeric reversed phase media also performs well at high pH and is often buffered with ammonium hydroxide or ammonium bicarbonate (0.05-0.1 mol/dm3 at pH 8-9). 

No solvent system resolves all the Dns-amino acids by one-dimensional chromatography and, also, TD chromatography requires more than two runs for a complete resolution. The most common used eluents on polyamide layers are benzene-acetic acid (9 1), toluene-acetic acid (9 1), toluene-ethanol-acetic acid (17 1 2), water-formic acid (200 3), water-ethanol-ammonium hydroxide (17 2 1 and 14 15 1), ethylacetate - ethanol- ammonium hydroxide... 

Eluents and regenerents suitable for the analysis of organic acids when applying an AFS-2 hollow fiber membrane suppressor are listed in Table 4-2. For the analysis of borate and carbonate with octanesulfonic acid as the eluent, an ammonium hydroxide solution with a concentration c = 0.01 mol/L can also be used as the regenerent. 

Figure 11.2. Separation of Cr(IIl) and Cr(VI) by valveless IC and JCP-MS detection. The separation is affected by both the volume of sample introduced to the column and the speed of the peristaltic pump. The eluent was 0.35 % (w/w) nitric acid adjusted to pH 1.6 with ammonium hydroxide. The column is a low-capacity anion exchanger ANX3202 with dimensions of 3.2 x 20 mm. Detection limits for Cr(IlI) and Cr(Vl) are both <0.1 ppb. Courtesy of Transgenomic, Inc., Omaha, NE.

Sample preparation Activate a 1 mL Bond-Elut C8 SPE cartridge with 2 mL MeOH then 1 mL 10 mM HCl, do not allow it to dry completely. Sonicate 1 mL whole blood for 20-30 min then apply to cartridge. Wash with 100 p,L water, elute with three 500 pL portions of MeOH MeCN 1% aqueous ammonium hydroxide 50 20 30, combine eluents and evaporate to dryness under a stream of nitrogen at 40°. Redissolve in 1 mL MeOH, inject a 20 pL aliquot. 

Sample preparation Equilibrate a Sep-Pak silica SPE cartridge with 5 mL ethyl acetate. 1 mL Serum -i- 3 mL 5% trichloroacetic acid -I- 4 mL ethyl acetate, vortex vigorously, centrifuge at 1500 g for 5 min. Remove organic layer and repeat extraction twice with 3 mL portions of ethyl acetate. Combine extracts, evaporate to about 1.5 mL, add to the SPE cartridge. Wash with 8 mL ethyl acetate, elute with 4 mL MeOH ammonium hydroxide (90 10). Evaporate the eluent to dryness under nitrogen, reconstitute in 100 jiL MeOH, inject. 

The germanium internal standard was made by diluting a 1000 mg L aqueous commercial standard to 10 mg/L in 300 mM NH4OH. The reason for using ammonium hydroxide was to avoid the precipitation of germanium oxide when the internal standard was mixed with the IC effluent. The eluents were made by dissolving the appropriate amount of pure material in... 

Peptide maps of the tryptic digest of myosin have been performed on thin-layer plates (20 x 20 cm) by successive TLC and electrophoresis. In the first-dimension TLC with chloroform-methanol-ammonium hydroxide 34% (40 40 20, v/v) as eluent, the time was as long as 60 min. The second-dimension electrophoresis with pyridine-glacial acetic acid-water (1 10 489, v/v) buffer and 980 V, 30 mA current, the time was 1 hr. The peptide mixture is applied in amounts of 0.05 to 0.5 mg per peptide map. " In another paper, electrophoresis was applied in one direction on buffered adsorbents, followed by chromatography in the second dimension. Here, phosphate esters were separated by TLC development twice with n-propanol-ammonium hydroxide-water (60 30 1, v/v), and electrophoresis was carried out in 0.28 M acetate buffer (pH 3.6), 1000 V, 35 mA, and 16 min. 

---