Search results for "Pill"
showing 10 items of 1870 documents
Interfaces between coexisting phases of polymer mixtures: Comparison between Monte Carlo simulations and theoretical predictions
1997
Large scale Monte Carlo investigations of the interface between A-rich and B-rich phases of symmetric binary (AB) polymer mixtures are presented, using the bond fluctuation model of flexible chains with NA=NB=N=32 effective monomers. The temperature range studied, 0.144<T/Tc0.759, includes both the strong and the weak segregation limit. Interfacial free energy and interfacial structure are studied, and compared to predictions based on the selfconsistent field theory. Also the broadening of the interfacial width due to capillary waves is considered, and finite size effects due to the confinement of interfaces in thin films of polymer blends are discussed.
Simultaneous determination of C1−C8 n-alkyl acetates and corresponding mono-, di- and trichloroacetates on glass capillary columns with programmed te…
1982
Gas chromatography of mixtures of aliphaticn-alkyl acetates (CH3−COOR), chloroacetates (CHCl2−COOR), dichloroacetates (CHCl2−COOR) and trichloroacetates (CCl3−COOR), where the alcohol chain length (R) varied between 1 and 8, has been studied on SE-30, Carbowax 20M and OV-351 glass capillary columns with programmed temperatures from 50°C at 2, 4, 6, 8 and 10°C/min. Compounds in the homologous series are eluted in the direct order from methyl ton-octyl acetate. The isomeric chloro esters are eluted on SE-30 according to their boiling points in the order: mono-, di- and trichloro isomer, whereas on polar columns di- and trichloro esters are eluted in the reverse order. The complete separation …
Enzyme-assisted extraction of proteins from Citrus fruits and prediction of their cultivar using protein profiles obtained by capillary gel electroph…
2017
Abstract The suitability of protein profiles established by capillary gel electrophoresis (CGE) as a tool to discriminate between 11 cultivars of Citrus (orange and tangerine) peel and pulp was evaluated in this work. Before CGE analysis, different extraction buffers (which included enzyme-assisted treatments) were compared. The best results were achieved using 5% ( v/v ) Celluclast ® 1.5 L and 5% ( v/v ) Palatase ® 20,000 L buffers for Citrus peel and pulp protein extracts, respectively. The resulting protein profiles obtained were used to construct linear discriminant analysis (LDA) models able to distinguish Citrus peel and pulp samples according to their cultivar. In both cases, all sam…
Discontinuous electrokinetic chromatography of parabens using different substituted resonances as pseudostationary phases
1999
Resorcarene derivatives, negatively charged even at moderate pH, were synthesized and employed as pseudostationary phases to achieve mobilities exceeding that of the electroosmotic flow. Under these conditions, a discontinuous electrolyte system was developed which allows the separation of four uncharged homologous 4-hydroxybenzoic esters (parabens) within a zone of resorcarene electrolyte, and the detection of these UV active compounds in a resorcarene-free zone, free from the high UV background absorbance of the resorcarenes. Resorcarenes, with differently charged functionalities (carboxylate and phosphate groups) to provide the electrophoretic mobility and with alkyl residues of differen…
Simultaneous gas chromatographic determination of aliphatic C2−C20 n-carboxylic acids and their methyl esters using SE-30 and OV-351 quartz capillary…
1983
Simultaneous determination of aliphatic C2−C20 carboxylic acids and their methyl esters was carried out using SE-30 and OV-351 quartz capillary columns with temperature programming. Complete resolution of all 36 components was achieved. On SE-30 the methyl ester and the corresponding free acid are eluted in turn, whereas on OV-351 acetic acid eluted after methyl octanoate, after which the Cn methyl ester and Cn-6 carboxylic acid (n>9) are eluted one after the other. A non-polar SE-30 column is better for long-chain acids giving sharp peaks without tailing, the analysis time of the mixture being less than 16 minutes. The weight response correction factors for compounds under optimum operatin…
Gas chromatography of homologous esters
1985
Abstract The retention behaviour of C 1 C 18 n -alkyl esters of butanoic 2-, 3- and 4-chlorobutanoic acids was examined isothermally at several temperatures on SE-30 and OV-351 capillary columns. Retention increments showing the effects of each position of chlorine substitution are presented. The considerable enhancement of terminal chlorine substitution is discussed together with the corresponding behaviour of the monochloropropanoate esters.
Direct acid-catalysed mechanical depolymerisation of fibre sludge to reducing sugars using planetary milling
2016
Abstract This study performed a direct solvent-free acid-catalysed mechanical depolymerisation of fibre sludge to reducing sugars which involves one step of acid milling in a planetary mill. The common reported ‘solvent-free’ mechanocatalytic depolymerisation of lignocellulose which includes 1) acid impregnation, 2) vacuum evaporation and 3) mechanocatalytic depolymerisation was also performed as a reference. The major converted monosaccharides were determined by capillary electrophoresis and the results of total reducing sugar (TRS) yields were carried out based on the 3,5-dinitrosalicylic acid (DNS) method. The results showed that the TRS conversion of direct acid-catalysed mechanical dep…
Determination of cationic surfactants by capillary zone electrophoresis and micellar electrokinetic chromatography with deoxycholate micelles in the …
2000
Mixtures of the cationic surfactants benzalkonium chloride (BKC) and cetylpyridinium chloride (CPC) were quickly resolved and reproducibly and reliably determined by using background electrolytes (BGEs) containing 80 mM borate, pH 8.5, bile salts and large concentrations of an organic solvent. When the bile salt is present, the separation mechanism changes from capillary zone electrophoresis (CZE) to a mixed micellar electrokinetic chromatography (MEKC)-CZE, with predominant MEKC interactions, which lead to an excellent resolution of all the solutes, including the C12-C18 homologues of BKC and CPC. A BGE containing 50 mM sodium deoxycholate and 30% ethanol for an extreme resolution, or 20% …
Characterization of totally chlorine-free effluents from Kraft pulp bleaching
1999
A capillary zone electrophoresis (CZE) method for analyzing the total acid hydrolysis products (monosaccharides and their derivatives) of the dissolved carbohydrates from a totally chlorine-free bleaching plant was developed. Several borate buffer concentrations and other running conditions were tested. Neutral monosaccharides (arabinose, galactose, glucose, mannose, rhamnose and xylose) in hydrolysates were derivatized by means of 4-aminobenzonitrile and resolved by 500 mM borate buffer (pH 9.5, 16.0 kV). The detection level was less than 10 fmol. In addition, the separation of some uronic acids and oligosaccharides was studied.
Prediction of the curing time of Spanish hams using peptide profiles established by capillary zone electrophoresis
2009
Abstract A capillary zone electrophoresis procedure for the prediction of curing time of Spanish hams using peptide profiles has been developed. Excellent resolution between the seven peptide peaks was achieved within 30 min analysis time with a BGE containing 60 mM MgSO 4 and 50 mM phosphate at pH 2.5. Using hams with curing times of 6, 8 and 12 months, both linear discriminant analysis (LDA) and multiple linear regression (MLR) models were constructed. In both cases, two different normalisation procedures of the peak areas were compared. Using LDA, all the ham samples corresponding to the three categories were correctly classified. Using MLR, the ham curing time could be predicted with av…