# US 2021/0239659 A1 · Lc/ms adduct mitigation by vapor deposition coated surfaces > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239659 A1 - Document ID: US20210239659A1 - Status: Published application - Kind: A1 - Application number: 17/150,802 - Filed: 2021-01-15 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Waters Technologies Corporation - Applicants: Waters Technologies Corporation - Inventors: Kerri M. Smith; Paul Rainville - Web page: https://patentgrep.com/patent/US20210239659A1 ## CPC - G01N 30/56: Packing methods or coating methods - G01N 30/72: Mass spectrometers {(mass spectrometers per se H01J49/00)} - C23C 14/046: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates} - C23C 14/12: Organic material - G01N 2030/027: {Liquid chromatography} - G01N 2030/567: {coating} - G01N 2030/8831: {involving peptides or proteins} - 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) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract The present disclosure discusses a method of separating a sample (e.g., small organic acid metabolite) including coating a flow path of a chromatographic system. The coating along the flow path is vapor deposited and prevents or severely decreases metal interactions between the metallic chromatographic system and the sample. ## Claims ### Claim 1 A method of separating and analyzing a sample comprising: injecting the sample into a chromatographic system having a fluid-contacting coating on a metallic surface, wherein the coating comprises an alkylsilyl, and the sample comprises one or more tricarboxylic acid cycle metabolites; flowing the injected sample through the chromatographic system; separating the flowing sample with the chromatographic system; and analyzing the separated sample with a mass spectrometer. ### Claim 2 (depends on 1) The method of claim 1, wherein the one or more tricarboxylic acid cycle metabolites comprise a carboxylic group. ### Claim 3 (depends on 1) The method of claim 1, wherein the one or more tricarboxylic acid cycle metabolites comprise at least one tricarboxylic acid metabolite selected from the group of citric acid, itaconic acid or 2-hydroxyglutaric acid. ### Claim 4 (depends on 1) The method of claim 1, wherein the coating prevents tricarboxylic acid cycle metabolite interaction with metals, the coating comprising bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane. ### Claim 5 (depends on 1) The method of claim 1, wherein separating the sample comprises using a mixed mode anion exchange chromatographic method. ### Claim 6 (depends on 5) The method of claim 5, wherein using a mixed mode anion exchange chromatographic method comprises using a mobile phase of water and acetonitrile each containing formic acid. ### Claim 7 (depends on 5) The method of claim 5, wherein using a mixed mode anion exchange chromatographic method comprises using a phenyl-hexyl chromatographic column. ### Claim 8 (depends on 1) The method of claim 1, wherein the metallic surface comprises column walls and frit surfaces, and wherein the coating on the metallic surface increases metabolite peak area relative to a non-coated metallic surface. ### Claim 9 A method of increasing resolution of a sample comprising one or more tricarboxylic acid cycle metabolites when using a chromatographic system, the method comprising: providing the chromatographic system having a fluid-contacting coating on a metallic surface, wherein the coating comprises an alkylsilyl; injecting the sample into the chromatographic system; flowing the injected sample through the chromatographic system; separating the flowing sample with the chromatographic system; and passing the separated sample through a mass spectrometer to analyze the separated sample. ### Claim 10 (depends on 9) The method of claim 9, wherein selecting the alkylsilyl of the coating comprises assessing polarity of the sample; selecting a desired contact angle and coating material based on the polarity assessment; and adjusting hydrophobicity of the sample flow path by vapor deposition of alkylsilyl. ### Claim 11 (depends on 9) The method of claim 9, wherein the one or more tricarboxylic acid cycle metabolites comprise a carboxylic group. ### Claim 12 (depends on 9) The method of claim 9, wherein the one or more tricarboxylic acid cycle metabolites comprise at least one tricarboxylic acid metabolite selected from the group of citric acid, itaconic acid or 2-hydroxyglutaric acid. ### Claim 13 (depends on 9) The method of claim 9, wherein the metallic surface comprises column walls and frit surfaces, and wherein the coating on the metallic surface increases metabolite peak area relative to a non-coated metallic surface. ### Claim 14 (depends on 9) The method of claim 9, wherein the coating prevents tricarboxylic acid cycle metabolite interaction with metals, the coating comprising bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane. ### Claim 15 A method of studying etiology of a disease, the method comprising: injecting the sample into a chromatographic system having a fluid-contacting coating on a metallic surface, wherein the coating comprises an alkylsilyl, and the sample comprises one or more tricarboxylic acid cycle metabolites; flowing the injected sample through the chromatographic system; separating the flowing sample with the chromatographic system; and analyzing the separated sample with a mass spectrometer. ### Claim 16 (depends on 15) The method of claim 15, wherein the one or more tricarboxylic acid cycle metabolites comprise a carboxylic group. ### Claim 17 (depends on 15) The method of claim 15, wherein the one or more tricarboxylic acid cycle metabolites comprise at least one tricarboxylic acid cycle metabolite selected from the group of citric acid, itaconic acid or 2-hydroxyglutaric acid. ### Claim 18 (depends on 15) The method of claim 15, wherein the coating prevents tricarboxylic acid cycle metabolite interaction with metals, the coating comprising bis(trichlorosilyl)ethane or bis(trimethoxysilyl)ethane. ### Claim 19 (depends on 15) The method of claim 15, wherein the metallic surface comprises column walls and frit surfaces, and wherein the coating on the metallic surface increases metabolite peak area relative to a non-coated metallic surface. ### Claim 20 (depends on 15) The method of claim 15, wherein the coating covers 90% of the surfaces of the sample flow path.