Phases cyanopropyl

NMR-guided fractionation yielded benzomalvin C (7) from P. raistrickii in our study. The methylene chloride extract of H10BA2 was resolved by LH-20 size exclusion chromatography (chloroform/methanol, 1 1) into ten fractions. Fraction 2 was further resolved by reverse-phase HPLC (Rainin C8 semipreparative, 50% methanol/water - 100% methanol), yielding eighteen fractions. Fraction 13 of this separation exhibited most of the aromatic peaks of interest in the HNMR, so it was applied to a silica gel HPLC colunm (10% isopropanol/hexane) and was ultimately purified by HPLC, using a bonded phase cyanopropyl column (Rainin CNPr, 20% isopropanol/hexane). 

This experiment describes a quantitative analysis for the active ingredients in a prescription antipsychotic medication. The separation makes use of a cyanopropyl derivatized column and a mobile phase of 70% v/v acetonitrile, 5% v/v methanol, and 25% v/v 0.1 M aqueous KH2PO4. A UV detector set to 215 nm is used to measure the eluent s absorbance. 

Haliclonacyclamine E (13) and arenosclerins A (14), B (15), and C (16) have been isolated from the marine sponge Arenosclera brasiliensis, endemic in Brazil. Crude extracts of this sponge displayed potent cytotoxic and antibiotic activities, and were subjected to fractionation by sihca-gel flash chromatography, medium pressure chromatography on a SiOH cyanopropyl-bonded column, and reversed-phase Cis column chromatography to give compounds 13-16 [18]. The structure elucidation was based on spectroscopic analysis, including HRFABMS, COSY, HSQC, HSQC-TOCSY, and HMBC NMR... 

Silica has often been modified with silver for argentation chromatography because of the additional selectivity conferred by the interactions between silver and Jt-bonds of unsaturated hydrocarbons. In a recent example, methyl linoleate was separated from methyl linolenate on silver-modified silica in a dioxane-hexane mixture.23 Bonded phases using amino or cyano groups have proved to be of great utility. In a recent application on a 250 x 1-mm Deltabond (Keystone Scientific Belief onte, PA) Cyano cyanopropyl column, carbon dioxide was dissolved under pressure into the hexane mobile phase, serving to reduce the viscosity from 6.2 to 1 MPa and improve efficiency and peak symmetry.24 It was proposed that the carbon dioxide served to suppress the effect of residual surface silanols on retention. 

Achiral-chiral chromatography has also been accomplished using subcritical fluid chromatography (Phinney et al., 1998). In this work, the structurally related [3-blockers, 1,4-benzodiazepines, and two cold medicines were separated using methanol or ethanol modified carbon dioxide mobile phases. The (3-blockers were separated using cyanopropyl and Chiracel OD columns connected in series. Likewise, an amino bonded phase and Chiracel OD column were used for the separation of the 1,4-benzodiazepines. Guaifenesin and phenylpropanolamine from cough syrup were separated on cyanopropyl and Chiralpak AD columns in series. 

M.A. Hawryl, A. Hawryl and E. Sochewinski, Application of normal- and reversed-phase 2D TLC on a cyanopropyl-bonded polar stationary phase for separation of phenolic compounds from the flowers of Sambucus nigra L. J. Planar Chromatogr.-Mod. TLC 15 (2002) 4-10. 

The ethyl acetate solution of organic species from the pre-treatment scheme shown in Figure 1 is suitable for analysis by this method. In order to cover the range of common explosives several chromatography columns with different types of stationary phase are required to allow for difierent polarities and volatihties. Dimethylsiloxane, phenyl-modified dimethylsiloxane, cyanopropyl- phenyl- vinyl-modified dimethylsiloxane, and polyethylene glycol have been found to represent a useful set of stationary phases. Carefully optimised temperature programming is also needed to obtain the requisite resolution and avoid interferences [19, 20]. 

Cyano or nitrile phases are prepared by the reaction of silica with 3-cyanopropyl silane. They are also polar with weak retention in RPC. It is difficult to determine whether the polar interaction of this phase is caused by the dipole of the nitrile group or by residual silanols. There is a lack of significant studies of retention mechanisms with this phase. 

In adsorption TLC, selectivity is mostly determined by the developing solvent system, whereas in RP-TLC the selectivity is determined primarily by the reversed-phase support and degree of carbon loading on the silica gel base. It should be kept in mind that the coating material of RP-TLC plates will always contain a certain amount of underivatized silanols that will confer to the plates some adsorptive and ionic characteristics that affect selectivity. It is, therefore, erroneous to think that all RP-Q, C8, C18, cyanopropyl, and diphenyl materials will behave similarly and it is strongly suggested that, in an optimization process, an investigator should experiment with plates from different suppliers. 

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