Solvent delivery with a reduced volume single stroke pumping arrangement providing continuous solvent flow

A solvent delivery system for a chromatography system having a chromatography column from which analytes of interest elute, comprising:

• a first pump with a single plunger for pumping a first component of a solvent gradient over a first fluid path to the mixing tee, the first pump having a repeating operational cycle with a delivery phase and a refilling phase;
• a second pump with a single plunger for pumping a second component of the solvent gradient over a second fluid path to the mixing tee, the second pump having a repeating operational cycle with a delivery phase and a refilling phase;
• a first proportioning valve connected to an input of the first pump for providing proportions of multiple solvents for the first component of the solvent gradient to the first pump;
• a second proportioning valve connected to an input of the second pump for providing proportions of multiple solvents for the second component of the solvent gradient to the second pump;
• and
• one or more processors configured to control the first pump and the second pump so that:
• as the first pump is in the refilling phase, the second pump is in the delivery phase, and
• as the second pump is in the refilling phase, the first pump is in the delivery phase;
• and
• wherein the refilling phases of the first pump and the second pump do not occur during the eluting of the analytes of interest from the chromatography column.