Alcohols, electrophoresis

Indirect UV absorbance detection in capillary zone electrophoresis has been used to analyze sodium alcohol sulfates. Excellent reproducibility was obtained when veronal buffer was used as UV-absorbing background electrolyte [302],... 

Foumand, D. Cathala, B. Lapierre, C. Initial steps of the peroxidase-catalyzed polymerization of coniferyl alcohol and/or sinapyl aldehyde capillary zone electrophoresis study of pH effect. Phytochemistry 2003, 62, 139-146. 

Miniaturized columns have provided a decisive advantage in speed. Uracil, phenol, and benzyl alcohol were separated in 20 seconds by CEC in an 18 mm column with a propyl reversed phase.29 A19 cm electrophoretic channel was etched into a glass wafer, filled with a y-cyclodextrin buffer, and used to resolve chiral amino acids from a meteorite in 4 minutes.30 A 6 cm channel equipped with a syringe pump to automate sample derivatization was used to separate amino acids modified with fluorescein isothiocyanate.31 Nanovials have been used to perform tryptic digests on the 15 nL scale for subsequent separation on capillary Electrophoresis.32 A microcolumn has also been used to generate fractions representing time-points of digestion from a 40 pL sample.33 A disposable nanoelectrospray emitter has been... 

Effect of adsorbed polymer on the double-layer. Because of the presence of adsorbed train segments, the double layer is modified. The zeta-potential, , is displaced because the adsorbed polymer displaces the plane of shear. The parameters for describing adsorbed polymers are the fraction of the first layer covered by segments, 0, and the effective thickness, A, of the polymer layer, The insert gives the distribution of segments over trains and loops for polyvinyl alcohol adsorbed on silver iodide. Results obtained from double layer and electrophoresis measurements. 

Pranaityte, B., Daunoravicus, Z., and Padarauskas, A. (2004). Development and validation of a capillary electrophoresis method for the determination of denatonium benzoate in denaturated alcohol formulations. Chromatographia 60(5 — 6), 353 — 357. 

The recent introduction of non-aqueous media extends the applicability of CE. Different selectivity, enhanced efficiency, reduced analysis time, lower Joule heating, and better solubility or stability of some compounds in organic solvent than in water are the main reasons for the success of non-aqueous capillary electrophoresis (NACE). Several solvent properties must be considered in selecting the appropriate separation medium (see Chapter 2) dielectric constant, viscosity, dissociation constant, polarity, autoprotolysis constant, electrical conductivity, volatility, and solvation ability. Commonly used solvents in NACE separations include acetonitrile (ACN) short-chain alcohols such as methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH) amides [formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA)] and dimethylsulfoxide (DMSO). Since NACE—UV may present a lack of sensitivity due to the strong UV absorbance of some solvents at low wavelengths (e.g., formamides), the on-line coupling of NACE... 

Figure 26-19 Comparison of peak widths for benzyl alcohol (C6H5CH2OH) in capillary electrophoresis and HPLC. [From s. Fazio,... 

The observed behavior of benzyl alcohol (C6H5CH2OH) in capillary electrophoresis is given here. Draw a graph showing the number of plates versus the electric field and explain what happens as the field increases. 

Electrophoresis does not show the presence of uncharged species, such as undissociated metal alcoholate or carbohydrate-metal hydroxide adducts. These species are probably present in alcoholic solutions, but their concentration has not yet been ascertained. Their presence is suggested by the relatively low mobility of carbohydrates in alcoholic solutions of alkali metal hydroxide. In aqueous media, where greater dissociation of ion pairs should occur, the mobility is extremely high. The possible existence of free carbohydrate-hydroxide ion species cannot be disregarded, because of the hydrogen-bonding properties of the hydroxide ion. 

Paper electrophoresis -ofpolyols and carbohydrates [SUGAR ALCOHOLS] (Vol 23)... 

ALCOHOLS,HIGHERALIPHATIC - SURVEY ANDNATURALALCOHOLSMANUFACTURE] (Vol 1) -use m electrophoresis [ELECTROSEPARATIONS - ELECTROPHORESIS] (Vol 9)... 

Identification of oat (Avena) cultivars by HPLC was first reported by Lookhart and coworkers (153-155) in combined electrophoresis/HPLC experiments. The HPLC technique used was a modification of the procedure described by Bietz (137) for wheat. Generally, the prolamin fraction, i.e., the alcohol-soluble fraction, of oat species generates complex polyacrylamide gel-electrophoresis (PAGE) and RP-HPLC patterns, with increasing complexity as ploidy of the selections increased. Readily (visible) identification of the cultivars was possible only when PAGE and RP-HPLC results were combined. An HPLC procedure for the characterization of the major oat protein fractions was developed by Lapvetelainen et al. (156). Salt-soluble, alcohol-soluble, and alkali-soluble protein fractions were extracted with 0.1 M NaCl, 52% ethanol, and 1% SDS in 0.05 M borate (pH 10), respectively. For the five cultivars examined, RP-HPLC separations of salt- and alkali-soluble proteins were very similar, whereas the prolamin fraction enabled culti-var differentiation, except for very closely related cultivars. 

Fluorescence/capillary array electrophoresis amines, alcohols, etc. 25... 

Latexes initiated with persulfate normally have terminal sulfate groups, but these can be hydrolyzed to alcohols and then oxidized to carboxyl groups. Terminal alcohol groups also result from hydrogen peroxide or hydroperoxide initiated polymerization. Ottewill and Shaw (22) first showed by electrophoresis that latexes stripped of salts and emulsifiers by dialysis have both strong and weak acid sites. Van den Hul and Vanderhoff (23) then found that conductometric titrations were most effective for... 

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