Methods to increase sensitivity of LC/MS analysis

Patent metadata

Field	Value
Publication number	US-11530966-B2
Application number	US-202117150793-A
Country	US
Kind code	B2
Filing date	Jan 15, 2021
Priority date	Jan 17, 2020
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

The present disclosure discusses a method of separating a sample (e.g., pharmaceutical drug, genotoxic impurity, biomarker, and/or biological metabolite) including coating a metallic flow path of a chromatographic system; injecting the sample into the chromatographic system; flowing the sample through the chromatographic system; separating the sample; and analyzing the separated sample using mass spectroscopy. In some examples, the coating applied to the surfaces defining the flow path is non-binding with respect to the sample—and the separated sample. Consequently, the sample does not bind to the low-binding surface of the coating of the flow path. The applied coating can increase the chromatographic peak area for the sample of the chromatographic system.

First claim

What is claimed is:

1. A method of separating and analyzing a metal sensitive sample comprising:
providing a chromatographic system having an alkylsilyl surface coating;
injecting the sample into the chromatographic system, wherein the sample comprises one or more compounds having a sulfur dioxide constituent;
flowing the sample through the chromatographic system; and
separating the sample, wherein coating the metallic flow path of the chromatographic system increases a chromatographic peak area of the compounds in the sample of at least 1.6× in comparison to an uncoated chromatographic system having metallic surfaces exposed to fluids.

2. The method of claim 1 , wherein the sample does not bind to the coating of the metallic flow path.

3. The method of claim 1 , wherein the one or more of the compounds are diazoxide and/or bicalutamide.

4. The method of claim 1 , wherein providing a chromatographic system comprises: assessing a polarity of a compound in the sample; selecting a desired contact angle and coating material based on polarity assessment; coating a metallic flow path of the chromatographic system with an alkylsilyl surface coating, and adjusting hydrophobicity of the flow path by vapor deposition of an alkylsilyl.

5. The method of claim 1 , wherein the alkylsilyl surface coating comprises bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane.

6. A method of separating a sample comprising:
providing a chromatographic system having a metallic flow path with an alkylsilyl coating on fluid exposed surfaces, the metallic flow path with the alkylsilyl coating preventing the sample from binding to underlying metal surfaces;
injecting the sample into the chromatographic system, wherein the sample comprises one or more compounds having hydroxyl and nitrogen moieties which are in a spatial arrangement that allows the hydroxyl and nitrogen moieties to form chelates with metals;
flowing the sample through the chromatographic system; and
separating the sample, wherein coating the metallic flow path of the chromatographic system increases a chromatographic peak area of the compounds in the sample of at least 1.6× in comparison to an uncoated chromatographic system having metallic surfaces exposed to fluids.

7. The method of claim 6 , wherein the chromatographic system comprises a mix-mode chromatographic column.

8. The method of claim 6 , wherein the chromatographic system comprises a phenyl-hexyl chromatographic column.

9. The method of claim 6 , wherein the alkylsilyl coating comprises bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane.

10. The method of claim 6 , wherein one or more of the compounds are selected from the group consisting of salmeterol, apomorphine, and dobutamide.

11. A method of separating a sample comprising:
providing a chromatographic system having a metallic flow path with an alkylsilyl coating on fluid exposed surfaces, the metallic flow path with the alkylsilyl coating preventing the sample from binding to underlying metal surfaces;
injecting the sample into the chromatographic system, wherein the sample comprises N-nitrosodimethylamine (NDMA) and/or N-nitrosodiethylamine (NDEA);
flowing the sample through the chromatographic system; and
separating the sample, wherein coating the metallic flow path of the chromatographic system increases a chromatographic peak area of the NDMA and NDEA in a sample of at least 1.4× in comparison to an uncoated chromatographic system having metallic surfaces exposed to fluids.

12. The method of claim 11 , wherein the chromatographic system comprises a mix-mode chromatographic column.

13. The method of claim 11 , wherein the chromatographic system comprises a phenyl-hexyl chromatographic column.

14. The method of claim 11 , wherein the alkylsilyl coating comprises bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane.

Assignees

• Waters Technologies Corp

Inventors

• Rainville Paul
• Smith Kerri

Classifications

• G01N2030/8813

  biological materials · CPC title

• G01N2030/027

  Liquid chromatography · CPC title

• G01N1/405 Primary

  by adsorption or absorption · CPC title

• G01N2030/567

  coating · CPC title

• G01N30/7233

  interfaced to liquid or supercritical fluid chromatograph (interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04) · CPC title