| 摘要 |
<p>A method of isolating a charged, especially proteinaceous, compound comprises providing a prepared sample of the compound in solution, placing the prepared sample in contact with a membrane so limited in effective adsorptive surface area as to enable reversible binding to the membrane of the charged compound in the sample presented to the adsorptive surface such that solvent is removable therefrom and the charged compound is left substantially reversibly bound thereto, and eluting the compound from the membrane. Eluted compounds can then be directly subjected to mass spectrometric analysis for charcterisation of, for example, individual peptides. By virtue of the reduced effective adsorptive surface area of the membrane utilised, an irreversible adsorption of the major proportion of bound charged compounds in a lower part of the range of molecular weights thereof is prevented. In particular low molecular weight compounds, such as peptides of between 500 to 5,000 Daltons, can be therefore recovered by a subsequent elution step. The limited effective surface area of the membrane is preferably achieved by a maximum effective external face area of substantially 15 mm2, for preference 1 to 3 mm2, and a maximum thickness of about 500 microns, preferably 200 to 400 microns, with a pore size of about 0.5 to 5 microns.</p> |
