Waters Technologies Corporation

Craig Hamilton Dobbs

Joseph A Luongo

Sylvain Gilles Cormier

Richard Wayne Andrews

Robert Tacconi

A solvent delivery system for a liquid chromatography system may include a first gradient proportioning valve in fluidic communication with a first plurality of sources of solvent and producing therefrom a first low-pressure gradient stream. The solvent delivery system may further include a second gradient proportioning valve in direct fluidic communication with an inlet of the first gradient proportioning valve and with a second plurality of sources of solvent, the second gradient proportioning valve producing a second low-pressure gradient stream from the second plurality of sources of solvent, wherein one solvent source of the first plurality of sources of solvent used by the first gradient proportioning valve to produce the first low-pressure gradient stream comprises the second low-pressure gradient stream. The solvent delivery system may also include a first pump in direct fluidic communication with the first gradient proportioning valve to receive and pressurize the first low-pressure gradient stream.

Hybrid gradient delivery system and operation

A liquid chromatography system includes a gradient proportioning valve in fluidic communication with sources of solvent. From the solvent sources, the gradient proportioning valve produces a low-pressure gradient stream. A first pump is in fluidic communication with the gradient proportioning valve to receive, pressurize, and move the pressurized low-pressure gradient stream to a flow-combining device. A second pump operates in parallel with the first pump and moves a pressurized solvent stream to the flow-combining device where the pressurized solvent stream combines with the low-pressure gradient stream to produce a high-pressure gradient stream. A second gradient proportioning valve can produce, from a second plurality of sources of solvent, a second low-pressure gradient stream, wherein the solvent stream moved by the second pump to the flow-combining device and combined with the other low-pressure gradient stream comprises the second low-pressure gradient stream.

Described are a method and system for diluting a sample in a liquid chromatography system. A sample flowing at a first flow rate is combined for a predetermined time with a diluent flowing at a second flow rate to generate a volume of diluted sample. The diluted sample has a dilution ratio determined according to the two flow rates. A portion of the volume is loaded into a sample loop of an injection valve and subsequently injected into a mobile phase flowing to a chromatography column. The method eliminates the need to have a technician available to perform dilutions or to transfer the sample to a remote location for dilution. Advantageously, manufacturing or processing downtime to perform the dilution is not required and the amount of sample flowing to waste is reduced.

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Mendon, MA, United States of America

Craig Hamilton Dobbs