METHOD FOR FEEDING A SAMPLE INTO AN ANALYSIS BRANCH OF A LIQUID CHROMATOGRAPHY SYSTEM

• US 20150226710A1
• Filed: 02/10/2015
• Published: 08/13/2015
• Est. Priority Date: 02/10/2014
• Status: Active Grant

• Current Assignee: Dionex Softron GmbH (Thermo Fisher Scientific Incorporated)
• Original Assignee: Dionex Softron GmbH (Thermo Fisher Scientific Incorporated)
• Inventors: HOCHGRAEBER, Hermann
• Granted Patent: US 9,664,653 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60R 13/0206 Arrangements of fasteners and clips specially adapted for attaching inner vehicle liners or mouldings devices for fastening or securing F16B
• CPC Class Codes: B61D 17/08 Sides
• CPC Class Codes: B61D 17/18 Internal lining, e.g. insulating
• CPC Class Codes: F16B 21/02 Releasable fastening devices locking by rotation with snap-action F16B21/06; studs or coupling pins with resilient protrusions F16B21/08
• CPC Class Codes: F16B 37/044 Nut cages
• CPC Class Codes: F16B 5/0225 allowing for adjustment parallel to the plane of the plates
• CPC Class Codes: F16B 5/06 by means of clamps or clips F16B5/0004 takes precedence; friction-grip releasable fastenings in general F16B2/00
• CPC Class Codes: G01N 2030/027 Liquid chromatography
• CPC Class Codes: G01N 30/16 Injection G01N30/24 takes precedence
• CPC Class Codes: G01N 30/18 using a septum or microsyringe
• CPC Class Codes: G01N 30/24 Automatic injection systems

Abstract

The invention relates to a method for feeding a sample into an analysis branch of a liquid chromatography system, in particular a high-performance liquid chromatography system. A solvent or a solvent mixture from at least one solvent branch is supplied as volume flow {dot over (A)} into the analysis branch. At least one sample from at least one sample branch is fed as volume flow Ė into the analysis branch within a predetermined time interval. The volume flow {dot over (A)} is reduced to an extent during the predetermined time interval, and a volume flow Ċ resulting from the sum of the volume flows {dot over (A)} and Ė remains substantially constant in the analysis branch. The invention further relates to a sampler for carrying out a method of this kind.

Claims

1. A method for feeding a sample into an analysis branch of a liquid chromatography system, the method comprising:

supplying a solvent or a solvent mixture from at least one solvent branch at a volume flow {dot over (A)} into the analysis branch, the at least one solvent branch is an input into a unidirectional valve, the analysis branch is an output out of the unidirectional valve;

feeding at least one sample from at least one sample branch at a volume flow Ė

into the analysis branch within a predetermined time interval, the at least one sample branch is another input into the unidirectional valve

reducing the volume flow {dot over (A)} during the predetermined time interval;

outputting a substantially constant volume flow Ċ

in the analysis branch resulting from a sum of the volume flows {dot over (A)} and Ė

.

2. The method of claim 1, wherein the volume flow {dot over (A)} comes to a stop during the predetermined time interval

at least after introducing the sample into the analysis branch where a solvent pump is stopped and a metering device pump is started, the solvent pump being configured to pump a solvent into the solvent branch, the metering device pump being configured to pump the sample into the sample branch.

3. The method of claim 2, wherein the volume flow {dot over (A)} comes to a stop during the predetermined time interval,

at least after a first transition phase where the sample is introduced into the analysis branch, the solvent pump is stopped, and the metering device pump is started, and

at least before a second transition phase where the sample has already been introduced into the analysis branch, the solvent pump is started, and the metering device pump is stopped.

4. The method of claim 1, wherein the volume flow Ċ

corresponds to a maximum of the volume flow {dot over (A)} or Ė

.

5. The method of claim 3 further comprising:

stopping the volume flow Ė

of the sample into the unidirectional valve before a first rear end of the sample, with respect to a direction of a flow of the sample, reaches the analysis branch, the rear end being a transition between an end of the sample and a solvent, whereby a second rear end arises on the sample introduced into the volume flow Ċ

of the analysis branch.

6. The method of claim 1 further comprising:

collecting the sample from a vial; and

after collecting the sample from the vial, pressing an injection needle into a needle seat to introduce the sample to the sample branch, in which the needle seat is connected to the analysis branch via the unidirectional valve.

7. The method of claim 5 further comprising:

after introducing the sample to the sample branch and prior to collecting a further sample, automatically cleaning the injection needle by flushing.

8. The method as of claim 1, wherein the supplying of the solvent or the solvent mixture into the analysis branch is after or before the feeding of the at least one sample.

9. The method as of claim 2, in which the supplying of the solvent or the solvent mixture to the at least one solvent branch causes a ball in the unidirectional valve to close the sample branch

10. The method as of claim 9, in which the stopping of the solvent pump causes the ball to open the sample branch allowing the sample to feed into the analysis branch.

11. A sampler for a liquid chromatography system, the sampler comprising:

a) at least one injection needle where the at least one injection needled is controlled by a motor;

b) at least one needle seat where a tip of the at least one injection needle is configured to be sealingly pressed into the at least one needle seat;

c) a unidirectional injection valve including at least one sample branch attached to an input of the unidirectional injection valve, the sample branch being connected to the at least one needle seat, the analysis branch being connected to an output of the unidirectional injection valve, the analysis branch also being connected to at least one separating column, and at least one solvent branch being connected to an input of the unidirectional injection valve;

d) the unidirectional injection valve having one position where the sample branch is closed in a liquid-tight manner;

e) the valve having another position where the sample branch is open allowing the sample to feed from the sample branch into the analysis branch.

12. The sampler of claim 11, wherein the injection needle is connected to a sample loop.

13. The sampler of claim 11 further comprising:

a control device configured to control a solvent pump and a metering device pump so that a volume flow in the analysis branch is substantially constant, the solvent pump being configured to pump a solvent into the solvent branch, the metering device pump being configured to pump the sample into the sample branch.

14. The sampler of claim 11, in which the unidirectional valve comprises:

a ball configured to close the sample branch in the one position where the solvent flows into the unidirectional valve, and

the ball is configured to open the sample branch in the another position where the solvent flow into the unidirectional valve is stopped.

15. The sampler of claim 14 further comprising:

a spring configured to close the sample branch with the ball in the one position.