CONTROLLABLE INJECTOR SAMPLE DILUTION FOR A LIQUID CHROMATOGRAPHY SYSTEM

• US 20160069844A1
• Filed: 08/12/2015
• Published: 03/10/2016
• Est. Priority Date: 09/08/2014
• Status: Active Grant

• Current Assignee: Waters Technologies Corporation (Waters Corporation)
• Original Assignee: Waters Technologies Corporation (Waters Corporation)
• Inventors: Jackson, Michael R., Cormier, Sylvain
• Granted Patent: US 9,816,971 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2030/027 Liquid chromatography
• CPC Class Codes: G01N 2030/201 multiport valves, i.e. having more than two ports
• CPC Class Codes: G01N 2030/202 rotary valves
• CPC Class Codes: G01N 30/06 Preparation
• CPC Class Codes: G01N 30/20 using a sampling valve
• CPC Class Codes: G01N 30/24 Automatic injection systems

Abstract

Described are a method and a system for injecting a sample into a flow of a liquid chromatography system. The method includes combining a flow of a sample and a flow of a mobile phase to create a diluted sample in the system flow. The volumetric flow rate of the sample is controlled to be at a value that yields a desired dilution ratio for the diluted sample. The particular value at which the volumetric flow rate is maintained can be determined from the desired value of the dilution ratio and the volumetric flow rate of the mobile phase. System embodiments include a syringe that can be used to provide a sample solution at a controllable volumetric flow rate for combination with a high pressure mobile phase.

Claims

1. A method for injecting a sample into a flow of a liquid chromatography system, the method comprising:

providing a flow of a mobile phase at a first volumetric flow rate; and

combining a flow of a sample at a second volumetric flow rate and the flow of the mobile phase, wherein the combined flows create a diluted sample having a dilution ratio that is responsive to the first and second volumetric flow rates and wherein the first volumetric flow rate is controlled to a value so that the dilution ratio has a predetermined value.

2. The method of claim 1 wherein the sample includes a sample diluent.

3. The method of claim 2 wherein the dilution ratio is responsive to a dilution of the sample by the sample diluent and a dilution of the sample by the mobile phase.

4. The method of claim 2 wherein the sample diluent is a strong solvent and the mobile phase is a weak solvent.

5. The method of claim 1 wherein the mobile phase is a gradient mobile phase.

6. The method of claim 1 wherein the combining of the flow of the sample and the flow of the mobile phase occurs for a predetermined duration.

7. The method of claim 1 further comprising acquiring the sample from a sample source prior to combining the flow of the sample and the flow of the mobile phase.

8. A system for injecting a sample into a flow of a liquid chromatography system, the system comprising:

a syringe to dispense a sample;

a first fluid channel to conduct a mobile phase;

a second fluid channel in communication with the syringe to receive the sample;

a valve having a first port in communication with the first fluid channel, a second port in communication with the second fluid channel, and a third port, the valve having at least two states of operation, wherein, when the valve is in a first state, the first port is in communication with the third port and wherein, when the valve is in a second state, the first and second ports are in communication with the third port; and

a control module in communication with the syringe to control a volumetric flow rate of the sample dispensed from the syringe, the control module being in further communication with the valve to thereby control the state of operation of the valve, wherein the mobile phase conducted through the first fluid channel is dispensed from the third port when the valve is in the first state and wherein the volumetric flow rate of the sample is controlled to a value to obtain a predetermined sample dilution ratio of a diluted sample dispensed from the third port when the valve is in the second state.

9. The system of claim 8 wherein the sample includes a diluent.

10. The system of claim 8 wherein the second fluid channel comprises a sample needle.

11. The system of claim 10 further comprising a needle drive coupled to the sample needle and configured to move the sample needle to a position at which the sample needle is loaded with the sample and to a position at which the sample needle is configured to dispense the sample into the valve.

12. The system of claim 10 wherein the second fluid channel comprises an injection port configured to receive the sample needle.

13. The system of claim 8 wherein the control module comprises a first controller in communication with the syringe and a second controller in communication with the valve.

14. The system of claim 8 further comprising a solvent manager in communication with the first fluid channel.

15. The system of claim 8 wherein the mobile phase is a gradient mobile phase.

16. A computer program product for injecting a sample into a flow of a liquid chromatography system, the computer program product comprising:

a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to provide a flow of a mobile phase at a first volumetric flow rate; and

computer readable program code configured to combine a flow of a sample at a second volumetric flow rate and the flow of the mobile phase, wherein the combined flows create a diluted sample having a dilution ratio that is responsive to the first and second volumetric flow rates and wherein the first volumetric flow rate is controlled to a value so that the dilution ratio has a predetermined value.

17. The computer program product of claim 16 wherein the computer readable program code further comprises computer readable program code configured to acquire the sample from a sample source prior to combining the flow of the sample and the flow of the mobile phase.