Carbon dioxide based chromatography systems including multiple carbon dioxide pumps

Patent metadata

Field	Value
Publication number	US-10371673-B2
Application number	US-201815909264-A
Country	US
Kind code	B2
Filing date	Mar 1, 2018
Priority date	Mar 3, 2017
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

The present disclosure relates to methodologies, systems and apparatus for controlling pressure in a CO 2 -based chromatography system. A first CO 2 pump operates in constant flow mode and delivers CO 2 to a chromatography column, and liquid modifier is introduced to the chromatography column according to a gradient. A second CO 2 pump is disposed downstream of the column and operates in constant pressure mode to introduce CO 2 into a flow stream at an output of the column. Liquid modifier is also introduced into the flow stream at the output of the column according to a reverse gradient compared to the gradient entering the chromatography column.

First claim

What is claimed is:

1. A method of maintaining pressure in a CO 2 -based chromatography system, the method comprising:
introducing CO 2 into a mixer via a first CO 2 pump;
introducing liquid modifier into a mixer via a first liquid modifier pump;
receiving a mixture of CO2 and liquid modifier from the mixer at a chromatography column;
introducing CO 2 into a flow stream at an output of the column via a second CO 2 pump;
introducing liquid modifier into the flow stream at the output of the column via a second liquid modifier into pump;
controlling the second CO 2 pump to deliver liquid modifier according to a reverse pressure downstream of the column; and
controlling the second liquid modified pump to deliver liquid modifier according to a reverse gradient compared to a gradient introduced into the column from the first liquid modifier pump.

2. The method of claim 1 , further comprising introducing the flow stream at the output of the column into a detector.

3. The method of claim 2 , further comprising controlling the second liquid modifier pump such that a total flow rate of liquid modifier entering the detector is constant.

4. The method of claim 2 , wherein the detector is a flame ionization detector or a mass spectrometer.

5. The method of claim 1 , wherein the first CO 2 pump operates in a constant flow mode, and the second CO 2 pump operates in a constant pressure mode.

6. The method of claim 1 , wherein the second CO 2 pump and the second liquid modified pump introduce fluid into the flow stream at the output of the column via a tee fitting.

7. The method of claim 1 , wherein the second CO 2 pump and the second liquid modifier pump introduce fluid into the flow stream at the output of the column via a tee fitting.

8. The method of claim 7 , further comprising directing an output of the tee fitting to a detector via a fixed restrictor.

9. A CO 2 -based chromatography system comprising:
a first CO 2 pump disposed to deliver CO 2 to a chromatography column;
a liquid modifier pump;
a second CO 2 pump located downstream of the column and disposed to operate independently of the first CO 2 pump to introduce CO 2 into a flow stream at an output of the column, the second CO 2 pump operating in constant pressure mode in order to maintain a target pressure; and
an active splitter disposed to receive a liquid modifier from the liquid modifier pump, the active splitter disposed to deliver liquid modifier to the chromatography column according to a gradient, and further disposed to introduce liquid modifier into the flow stream at the output of the column according to a reverse gradient compared to the gradient entering the chromatography column.

10. A CO 2 based-pump system comprising:
a CO 2 pump;
a liquid modifier pump;
a first active splitter disposed to receive a liquid modifier from the liquid modifier pump, introduce the liquid modifier to a chromatography column according to a gradient, and introduce the liquid modifier into a flow stream downstream of the chromatography column according to a reverse gradient compared to the gradient entering the chromatography column; and
a second active splitter disposed to receive CO 2 from the CO 2 pump, introduce CO 2 to the chromatography column, and introduce CO 2 into the flow stream downstream of the chromatography column to maintain a target pressure.

Assignees

• Waters Technologies Corp

Inventors

• Fogwill Michael O
• Jarrell Joseph A
• Michienzi Joseph D
• Mcdonald Thomas S

Classifications

• G01N30/36

  in high pressure liquid systems · CPC title

• G01N30/32 Primary

  of pressure or speed (G01N30/36 takes precedence) · CPC title

• G01N30/34

  of fluid composition, e.g. gradient (G01N30/36 takes precedence) · CPC title

• B01D15/163

  Pressure or speed conditioning · CPC title

• G01N30/7233

  interfaced to liquid or supercritical fluid chromatograph (interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04) · CPC title