Abstract An aparatus for producing gradient elution in a liquid chromatographic system is diclosed. The apparatus comprises variable dosing means for at least two different solvents said dosing means including variable flow resistances for said solvents. A mixing means is provided for mixing said solvents and delivering a solvent mixture which is fed by pump means to a chromatographic column. Density measuring means is provided for measuring the density of said solvent mixture which density is a function of the mixing ratio of said different solvents. Control means responsive to said density measuring means adjust said flow resistances in accordance with a given nominal density curve corresponding to a desired elution gradient.
An apparatus for producing gradient elution in a liquid chromatographic system, said apparatus comprising variable dosing means for at least two different solvents said dosing means including variable flow resistances for said solvents; mixing means for mixing said solvents and delivering a solvent mixture; pump means for feeding said solvent mixture to a chromatographic column; density measuring means for measuring the density of said solvent mixture said density being a function of the mixing ratio of said different solvents; and control means responsive to said density measuring means for adjusting said flow resistances in accordance with a given nominal density curve corresponding to a desired elution gradient.
Claim 2
Independent Claim
107 words
An apparatus for producing gradient elution in a liquid chromatographic system, said apparatus comprising variable dosing means for at least two different solvents said dosing means including variable flow resistances for said solvents; mixing means for mixing said solvents and delivering a solvent mixture; pump means for feeding said solvent mixture to a chromatographic column; density measuring means for measuring the density of said solvent mixture said density being a function of the mixing ratio of said different solvents; and control means responsive to said density measuring means for adjusting said flow resistances in accordance with a given nominal density curve corresponding to a desired elution gradient.
Claim 3
Dependent Claim
15 words
The apparatus according to claim 1 wherein said variable flow resistance are adjustable needle valves.
Claim 4
Dependent Claim
21 words
The apparatus according to claim 1 wherein said density measuring means is a vibrating cell through which said solvent mixture flows.