Method and apparatus for flame ionization detection for chromatography

Patent metadata

Field	Value
Publication number	US-10852279-B2
Application number	US-201716092264-A
Country	US
Kind code	B2
Filing date	Apr 19, 2017
Priority date	Apr 20, 2016
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A method for detecting an analyte in a chromatography system includes performing a separation using a mobile phase that includes an organic component. The separation is performed with a primary separation module such as a chromatographic column. A first effluent, from the primary separation module, is modulated so that a fluidic plug containing an amount of the organic component and an analyte is provided to a secondary separation module where a secondary separation is performed. A second effluent, from the secondary separation module, includes temporally-resolved organic component and analyte peaks due to selective retention of the analyte. The second effluent is provided to a flame-based detector which is disabled when the organic modifier peak is received and enabled at least during the time when the analyte peak is received. Thus the analyte can be detected without interference from any response of the detector to the organic component peak.

First claim

The invention claimed is:

1. A method for detecting an analyte in a chromatography system using a flame-based detector, the method comprising:
performing a primary separation using a first mobile phase having a composition that includes an organic component, the primary separation generating a first effluent that includes the organic component and an analyte peak;
performing a secondary separation on a fluidic plug from the first effluent that includes the analyte peak, the secondary separation generating a second effluent that includes an organic component peak and the analyte peak, wherein the organic component peak and the analyte peak are temporally resolved;
providing the second effluent to a flame-based detector;
disabling the flame-based detector during a time when the organic component peak is received; and
enabling the flame-based detector during a time when the analyte peak is received.

2. The method of claim 1 wherein the organic component is a modifier.

3. The method of claim 1 wherein the organic component is an organic component from a group of organic components consisting of methanol, ethanol, isopropanol and acetonitrile.

4. The method of claim 1 wherein performing the secondary separation comprises switching a valve to direct the fluidic plug to a gas chromatography separation device.

5. The method of claim 4 wherein performing the secondary separation further comprises heating the gas chromatography separation device.

6. An apparatus for detecting an analyte in a chromatography system using a flame-based detector comprising:
a flame-based detector;
a primary separation module;
a secondary separation module having an outlet in communication with the flame-based detector;
a modulator having an inlet in communication with the primary separation module and an outlet in communication with an inlet of the secondary separation module; and
a controller in communication with the flame-based detector and the modulator, the controller configuring the modulator to provide a fluidic plug from a first effluent from the primary separation module that contains an analyte peak and an organic component to the secondary separation module, wherein the secondary separation module generates a second effluent having an organic component peak and the analyte peak, wherein the organic component peak and the analyte peak are temporally resolved and wherein the controller is configured to disable the flame-based detector during a time when the organic component peak is received at the flame-based detector and to enable the flame-based detector during a time when the analyte peak is received at the flame-based detector.

7. The apparatus of claim 6 wherein the organic component is a modifier.

8. The apparatus of claim 6 wherein the secondary separation module is a gas chromatography column.

9. The apparatus of claim 6 wherein the secondary separation module includes a source of a gas mobile phase.

10. The apparatus of claim 6 wherein the secondary separation module is a packed column.

11. The apparatus of claim 6 wherein the secondary separation module includes a source of a carbon dioxide mobile phase.

12. The apparatus of claim 6 wherein the modulator is one of a thermal modulator, a flow modulator, a trap and a loop.

13. The apparatus of claim 6 wherein the modulator and the secondary separation module are integrated as a single device.

14. The apparatus of claim 6 wherein the modulator comprises a valve having at least a first state and a second state, wherein the fluidic plug from the first effluent is directed to flow to the secondary separation module during the first state and the first effluent is prevented from flowing to the secondary separation module while in the second state.

15. The apparatus of claim 6 wherein the flame-based detector is one of a flame ionization detector and a flame photometric detector.

16. An apparatus for detecting an analyte in a chromatography system using a flame-based detector comprising:
a flame-based detector;
a first trap and a second trap;
a first gas chromatography separation device and a second gas chromatography separation device each in fluidic communication with the flame-based detector;
a modulator valve in fluidic communication with the first and second traps and the first and second gas chromatography separation devices, the modulator valve configured to receive a first effluent from a chromatographic column at a first port and to receive a gas chromatography carrier gas at a second port, the modulator valve switchable between a first state in which the first effluent is directed to flow into the first trap and the gas chromatography carrier gas is directed to flow through the second trap to the second gas chromatography separation device and a second state in which the first effluent is directed to flow into the second trap and the gas chromatography carrier gas is directed to flow through the first trap to the first gas chromatography separation device; and
a controller in communication with the flame-based detector and the modulator valve, the controller configured to switch the modulator valve between the first state and the second state.

17. The apparatus of claim 16 wherein the gas chromatography separation device is a gas chromatography column.

18. The apparatus of claim 16 wherein the controller is configured to disable the flame-based detector during a first duration of each of the first and second effluents when an organic component peak is received at the flame-based detector and to enable the flame-based detector during a second duration of each of the first and second effluents when an analyte peak is received at the flame-based detector.

19. The apparatus of claim 16 wherein the flame-based detector is one of a flame ionization detector and a flame photometric detector.

20. The apparatus of claim 16 wherein the first and second gas chromatography separation devices are integral with the first and second traps, respectively, and wherein the modulator valve is configured in the first state to direct the gas chromatography carrier gas through the second trap directly to the flame-based detector and configured in the second state to direct the gas chromatography carrier gas through the first trap directly to the flame-based detector.

Assignees

• Waters Technologies Corp

Inventors

• Fogwill Michael O
• Michienzi Joseph D
• Gerhardt Geoff

Classifications

• G01N30/68 Primary

  Flame ionisation detectors · CPC title

• G01N2030/025

  Gas chromatography · CPC title

• G01N30/30

  of temperature · CPC title