# US 2019/0170706 A1 · Method and apparatus for injecting a chromatographic sample

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- Number: US 2019/0170706 A1
- Document ID: US20190170706A1
- Status: Published application
- Kind: A1
- Application number: 16/098,280
- Filed: 2017-05-04
- Published: 2019-06-06
- Earliest claimed: 2016-05-05
- Assignees: Waters Technologies Corporation
- Applicants: Waters Technologies Corporation
- Inventors: Martin Gilar; Richard W. Andrews; Peyton C. Beals; Thomas McDonald; Keith Fadgen; Jordan Kornfeld; Geoff Gerhardt; Sylvain Cormier
- Web page: https://patentgrep.com/patent/US20190170706A1

## CPC

- G01N 30/24: Automatic injection systems
- B01D 15/14: relating to the introduction of the feed to the apparatus
- B01D 15/166: {Fluid composition conditioning, e.g. gradient}
- G01N 30/06: Preparation
- G01N 30/20: using a sampling valve
- G01N 30/34: of fluid composition, e.g. gradient (G01N30/36 takes precedence)
- G01N 1/38: Diluting, dispersing or mixing samples
- G01N 2030/207: {with metering cavity, e.g. sample loop}
- G01N 2030/347: {mixers}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

A method for injecting a diluted sample in a chromatography system includes merging a flow of a sample and a flow of a diluent to form a flow of a diluted sample. A dilution ratio of the diluted sample equals a sum of the volumetric flow rates of the sample and the diluent divided by the volumetric flow rate of the sample. The diluted sample is stored in a holding element before injection into a chromatographic system flow. Sample dilution occurs under low pressure relative to the chromatographic flow thereby allowing lower pressure sample and diluent syringes to be used. Other benefits include reduced compressibility and a reduction in leaks due to the lower pressure operation. The method avoids problems associated with manual techniques which can introduce errors due, for example, to loss of sample, sample precipitation and adsorption of sample to vials.

## Claims

### Claim 1

A method for injecting a diluted sample into a chromatographic system flow, comprising:
merging a first flow of a first volume of a sample at a first flow rate and a second flow of a second volume of a diluent at a second flow rate to form a third flow of a diluted sample, the sample comprising at least one analyte dissolved in a solvent, wherein a dilution ratio of the diluted sample equals a sum of the first and second flow rates divided by the first flow rate;
storing the diluted sample in a holding element; and
injecting the diluted sample stored in the holding element into a chromatographic system flow.

### Claim 2 (depends on 1)

The method of claim 1 wherein the first and second flows are provided from a sample syringe and a diluent syringe, respectively.

### Claim 3 (depends on 1)

The method of claim 1 wherein the first flow comprises a continuous flow of the sample and the second flow comprises a continuous flow of the diluent.

### Claim 4 (depends on 1)

The method of claim 1 wherein the first flow comprises discrete fluidic plugs of the sample and the second flow comprises discrete fluidic plugs of the diluent that are interleaved in time with the discrete fluidic plugs of the sample.

### Claim 5 (depends on 1)

The method of claim 1 wherein the dilution ratio of the diluted sample equals the sum of the first and second volumes divided by the first volume.

### Claim 6 (depends on 1)

The method of claim 1 wherein the holding element is a holding loop.

### Claim 7 (depends on 6)

The method of claim 6 wherein the sum of the first and second volumes is less than a volume of the holding loop.

### Claim 8 (depends on 1)

The method of claim 1 wherein the holding element is a trap column.

### Claim 9

An apparatus for diluting a chromatographic sample comprising:
a sample syringe to provide a flow of a sample;
a diluent syringe to provide a flow of a diluent;
a fluidic tee in communication with the sample syringe and the diluent syringe;
an injection valve in communication with the fluidic tee to receive a diluted sample therefrom and in communication with a chromatographic system flow path;
a holding element in communication with the injection valve; and
a control module in communication with the sample syringe, the diluent syringe and the injection valve, the control module controlling a first flow rate of the sample syringe and a second flow rate of the diluent syringe to thereby control a dilution ratio of the diluted sample, the control module controlling a state of the injection valve in one of a first state in which the diluted sample is loaded into the holding loop and a second state in which the diluted sample is injected from the holding loop into the chromatographic system flow path.

### Claim 10 (depends on 9)

The apparatus of claim 9 wherein the dilution ratio of the diluted sample equals the sum of the first and second flow rates divided by the first flow rate.

### Claim 11 (depends on 9)

The apparatus of claim 9 wherein the holding element is a holding loop.

### Claim 12 (depends on 11)

The apparatus of claim 11 wherein a volume of the diluted sample is less than a volume of the holding loop.

### Claim 13 (depends on 9)

The apparatus of claim 9 wherein the holding element is a trap column.

### Claim 14

A computer program product for injecting a diluted sample into a chromatographic system flow, 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 merge a first flow of a first volume of a sample at a first flow rate and a second flow of a second volume of a diluent at a second flow rate to form a third flow of a diluted sample, the sample comprising at least one analyte dissolved in a solvent, wherein a dilution ratio of the diluted sample equals a sum of the first and second flow rates divided by the first flow rate;
computer readable program code configured to store the diluted sample in a holding element; and
computer readable program code configured to inject the diluted sample stored in the holding element into a chromatographic system flow.

### Claim 15 (depends on 14)

The computer program product of claim 14 wherein the first flow comprises a continuous flow of the sample and the second flow comprises a continuous flow of the diluent.

### Claim 16 (depends on 14)

The computer program product of claim 14 wherein the first flow comprises discrete fluidic plugs of the sample and the second flow comprises discrete fluidic plugs of the diluent that are interleaved in time with the discrete fluidic plugs of the sample.

### Claim 17 (depends on 14)

The computer program product of claim 14 wherein the dilution ratio of the diluted sample equals the sum of the sum of the first and second volumes divided by first volume.