Chromatographic mobility

The product was identified through comparison of its infrared, proton magnetic resonance, and mass spectra and gas chromatographic mobility with authentic 1-decanal, available from Aldrich Chemical Company, Inc. 

This is not the case when high performance liquid chromatography (HPLC) and MS are considered where, due to the incompatibilities of the two techniques, they cannot be linked directly and an interface must be used, with its prime purpose being the removal of the chromatographic mobile phase. Unfortunately, no single... 

Figure 4-6. The Edman reaction. Phenylisothiocyanate derivatizes the amino-terminal residue of a peptide as a phenylthiohydantoic acid. Treatment with acid in a nonhydroxylic solvent releases a phenyithiohydantoin, which is subsequently identified by its chromatographic mobility, and a peptide one residue shorter. The process is then repeated.

The Determination of Fetal Hemoglobin (Hb-F). Specific properties of Hb-F have given rise to various methods for Its detection and quantitation which are based on electrophoretic and chromatographic mobilities of Hb-F, on Its slow rate of... 

Structural Analyses of Hemoglobin Variants It has become Impossible to characterize nearly any abnormal hemoglobin by Its electrophoretic and/or chromatographic mobility only This Is most strikingly demonstrated by the fact that over fifty different variants behave similar to Hb-S In electrophoresis Characterization, therefore, often requires detailed structural analyses or the demonstration of a property unique to a specific variant Some of the techniques used In these studies will be... 

Two different emulsion polymerization reactions were Investigated. One was the polymerization of acrylonitrile and methylacrylate (75/25 AN/MA) In the presence of an acrylonitrile elastomer (70/30 BD/AN) to produce a graft resin, llie second was the copolymerization oiE acrylonitrile and styrene (70/30 AN/S). Chromatographic analyses of latex solutions were conducted periodically during both types of polymerization reactions, using acetonitrile as latex solvent and chromatographic mobile phase. 

All three monomers were soluble In the chromatographic mobile phase and standard analytical techniques were used for calibration. Solutions containing known quantities of monomer were chromatographed to establish a peak area concentration relationship for the appropriate detector. The homopolymer of methylacrylate was also soluble In the mobile phase. Thus, both UV and refractometer detectors were calibrated for polymerized methylmethacrylate by chromatographing solutions of PM ... 

The reactor was charged with 37 elastomer which was Insoluble In the chromatographic mobile phase. Thus, the relationship between calculated and measured solids contents should have, and did, differ by at least 37 at low conversions. Expected formation of Insoluble graft polymer would also have Influenced relationship between calculated and measured total solids. 

Tscheme, R. J. and Umagat, H., Determination of isophenindamine in phen-indamine tartrate using an argentated high-performance liquid chromatographic mobile phase, /. Pharm. Sci., 69, 342, 1980. 

Compatibility of extraction solvent and chromatographic mobile phase... 

Sample preconcentration was performed by means of an automated on-line SPE sample processor Prospekt-2 (Spark Holland, Emmen, The Netherlands). Oasis HLB cartridges (Waters, Barcelona, Spain) were used to preconcentrate cannabi-noids present in the water samples whereas isolation of the rest of the compounds was done in PLRPs cartridges (Spark Holland). Before extraction, influent samples were diluted with HPLC water (1 9, v/v) to reduce matrix interferences and to fit some analyte concentrations, e.g., cocaine (CO) and benzoylecgonine (BE), within the linear calibration range. A sample volume of 5 mL was spiked with the internal standard mixture (at 20 ng/L) in order to correct for potential losses during the analytical procedure, as well as for matrix effects. Elution of the analytes to the LC system was done with the chromatographic mobile phase. 

For 2,3 5,6-di-O-isopropylidene-a-D-mannofuranose (183), separation of the anomeric products (184 and 185) was possible,135 and their structures were elucidated by periodate-oxidation studies. The configurational assignment for these products was based on the greater value of the specific rotation for the a anomer, as compared with that of the j3 anomer. The higher chromatographic mobility of one of the... 

H NMR and infrared spectral data of ( )-B, ( )-B methyl ester, and ( )-B methyl ester 3-benzoate were identical with those of AAn and the corresponding derivatives. Mass spectra of the methyl esters of ( )-B and AAn were identical. Chromatographic mobility of ( )-B relative to gibberellic acid (GA3) (as standard) was identical with that reported for AAn. Therefore, this synthesis also proved that antheridium inducing factor, AAn, must be regarded as possessing stereostructure B rather than A as originally supposed. 

The extracting solvent in this scenario is the chromatographic mobile phase, while the sample solvent is the stationary phase. Liquid-liquid partition chromatography is based on this idea. The mobile phase is a liquid that moves through a liquid stationary phase as the mixture components partition or distribute themselves between the two phases and become separated. The separation mechanism is thus one of the dissolving of the mixture components to different degrees in the two phases according to their individual solubilities in each. 

A chromatographic mobile phase consisting of acetonitrile/0.1 M sodium acetate buffer pH 4.0 (70 30) is prepared. Separate stock solutions in 250 ml of chromatographic mobile phase containing miconazole nitrate (200 20 mg) and econazole nitrate (200 20 mg) (internal standard) are prepared. 25 ml of econazole nitrate stock solution is transferred to five 100 ml volumetric flasks and varying amounts of miconazole stock solution 15, 20, 25, 30 and 35 ml are added to the five flasks. The flasks containing the calibration series are diluted to volume with mobile phase. A sample of cream containing 20 mg miconazole nitrate is shaken with 25 ml... 

Arylsulfonation of perimidines 78 (R = H or CF3) has been carried out in polyphosphoric acid and found to occur at the 6(7)- and 4(9)-positions. Separation of the product sulfones 79 and 80 was easily achieved due to their different chromatographic mobilities. The 4(9)-isomers 79 are more mobile due to the intramolecular hydrogen bond and, in low-polarity solvents, exist virtually completely as the 9-tautomer <2002CHE1084>. 

The (Z) and (E) isomers of 2-aryl-4-arylidene-5(4//)-oxazolones show different chromatographic behavior. In general, the relative chromatographic mobility of the (Z) and (E) isomers is dependent upon the oxazolone substituent and the chromatographic conditions. 

Comparative identification of a glycosyl ester of a nucleoside pyrophosphate with an authentic sample is usually based on the identity of their ultraviolet spectra and by comparison of chromatographic mobilities of the samples and their degradation products. In addition to paper-chromatographic techniques, it may be of value to use paper... 

D-apiose (1), characterized by optical rotatory data, paper-chromatographic mobility, and the melting point of the (p-bromophenyl)-osazone and the diisopropylidene acetal.20... 

Another indication that precipitation and not adsorption is operative depends on the observation that samples of the same molecular weight migrate identical distances from the dip line, independent of their starting positions on the TLC plate (15). This of course would not be the case if adsorption governed chromatographic mobility. To explain these phenomena, Inagaki has proposed that the solvent concentration profile results... 

Paper-Chromatographic Mobilities of Selected Deoxy Sugars... 

This acid resistant substance (16.3 mg) had aD + 93° (c = 0.4, H20) and was hydrolyzed by purified Candida tropicalis a-glucosidase (162) to D-glucose and a substance identified as levoglucosan on the basis of its nonreducing nature and chromatographic mobility, indistinguishable from levoglucosan (a preparation of which was obtained by catalytic deacetyla-... 

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