# US 12,181,450 B1 · Method of metered switching for a high-performance liquid chromatography sample injector

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- Number: US 12,181,450 B1
- Document ID: US12181450B1
- Status: Granted
- Kind: B1
- Application number: 18/581,221
- Filed: 2024-02-19
- Granted: 2024-12-31
- Earliest claimed: 2024-02-19
- Assignees: King Saud University
- Applicants: King Saud University
- Inventors: Ahmad Aqel Ifseisi; Mohamed Ali Ouladsmane; Ahmed Yacine Badjah Hadj Ahmed; Zeid Abdullah Alothman
- Web page: https://patentgrep.com/patent/US12181450B1

## CPC

- G01N 30/22: in high pressure liquid systems
- G01N 30/24: Automatic injection systems
- G01N 30/20: using a sampling valve
- G01N 2030/027: {Liquid chromatography}
- G01N 2030/207: {with metering cavity, e.g. sample loop}
- 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)

## Abstract

The method of metered switching for a high-performance liquid chromatography (HPLC) sample injector is a method of controlled switching for a HPLC sample injector to control the amount of the sample being transferred to the HPLC separation column. In a load mode of the HPLC sample injector, a sample to be tested is injected therein until a sample loop is filled. The HPLC sample injector is switched into an injection mode such that a pressurized mobile phase pushes the sample through the sample loop and out of an outlet port. The HPLC sample injector is then switched back into the load mode at a selected time corresponding to a desired volume of the sample to be dispensed from the outlet port. The time-dependent correspondence between a flow rate of the pressurized mobile phase and the desired volume of the sample for the sample loop is already known.

## Claims

### Claim 1

A method of metered switching for a high-performance liquid chromatography sample injector, comprising:
in a load mode of a high-performance liquid chromatography sample injector, injecting a sample into the high-performance liquid chromatography sample injector until a sample loop thereof is filled with the sample, wherein the sample loop is not in fluid communication with an outlet port of the high-performance liquid chromatography sample injector in the load mode;
switching the high-performance liquid chromatography sample injector into an injection mode wherein, in the injection mode, the sample loop is in fluid communication with a source of pressurized mobile phase and with the outlet port such that the pressurized mobile phase pushes the sample through the sample loop and out of the outlet port; and
switching the high-performance liquid chromatography sample injector back into the load mode at a selected time corresponding to a desired volume of the sample to be dispensed from the outlet port, wherein a time-dependent correspondence between a flow rate of the pressurized mobile phase and the desired volume of the sample for the sample loop is known.

### Claim 2 (depends on 1)

The method of metered switching for a high-performance liquid chromatography sample injector as recited in claim 1, wherein, in the load mode, the sample is injected into the high-performance liquid chromatography sample injector until a portion thereof is drained from a waste port in fluid communication with the sample loop.