Patent ID: 7416698

Claim:
A process for characterizing a sample comprising a population of linear macromolecules of interest and a population of long chain branched macromolecules of interest, the process characterized by the steps of: (a) providing a sample comprising a population of linear macromolecules of interest comprising a select fraction ( 104 ) and a population of long chain branched macromolecules of interest comprising a select fraction ( 103 ), said select fractions being of similar size, the similar size of the fractions of interest being characterized so that these fractions will co-elute in a size exclusion chromatography experiment optimized so that the fractions are separated by hydrodynamic size and the separation is conducted under temperature and solvent conditions which produce equivalent results to that obtained when the separation is conducted under isothermal and isocratic conditions; (b) providing a flow through separating medium ( 100 ) and a liquid eluant ( 101 ) in which the macromolecules of interest dissolve, the separating medium defining a multiplicity of flow through channels ( 102 ), which are small enough in diameter so that when the eluant containing dissolved sample macromolecules of interest is caused to flow under pressure through the channels ( 102 ) over a certain linear velocity range, the select fraction ( 104 ) of the population of the linear macromolecules of interest will elute before the select fraction ( 103 ) of the population of the long chain branched macromolecules of interest whereby separate peak elution volumes ( 105 ) and ( 106 ) of said fractions of linear macromolecules and long chain branched macromolecules of interest are established for producing differentiation of the fraction of linear macromolecules from the fraction of long chain branched macromolecules; (c) determining said linear velocity range; (d) introducing the sample of dissolved linear macromolecules of interest and long chain branched macromolecules of interest into the liquid eluant; (e) flowing the liquid eluant under pressure through the channels of the separating medium at a linear velocity that is within the range specified in step (c), whereby the sample macromolecules of interest emerge from the separating medium separated into successive elution volumes of the liquid eluant, characterized by said linear macromolecules of interest eluting ( 105 ) before said similarly sized long chain branched macromolecules of interest ( 106 ); and (f) differentiating the linear macromolecules of interest from the long chain branched macromolecules of interest based on their successive elution volumes established in step (e).