Metal components with inert vapor phase coating on internal surfaces
The invention provides metal liquid chromatography components with uniformly coated internal surfaces and methods for achieving the same. The invention addresses the problem of corrosion or interference of metal components in the flow path for LC analyses in which the sample interacts with metal ions or surfaces. The invention also alleviates the difficulties in coating very long metal tubes and very small metal channels with an inert, continuous coating that adheres well to metal surfaces. The metal flow path is rendered inert by the coating, and thus compatible with bioanalytical separations, for example, by using a vapor phase deposition process to coat the inner surfaces with a coating that continuously covers all metal surfaces in the flow path.
1. A metallic component having a lumen, passageway, or cavity having an interior surface continuously covered with a protective coating having a substantially uniform thickness of about 10 nm to about 5 μm wherein the protective coating is formed via a vapor phase process comprising: providing one or more molecular precursors in the gas phase; exposing an interior surface of the lumen, passageway or cavity to the one or more molecular precursors in the gas phase; allowing the one or more molecular precursors to react, decompose or otherwise change at or near the exposed interior surface and subsequently depositing thereon; and flushing with an inert gas, thus removing unreacted one or more molecular precursors and reaction byproducts, if any; wherein the metallic component is a chromatographic column comprising an inner diameter of less than 10 mm and a length greater than about 20 mm; wherein the protective coating comprises a material selected from SiC, Si 3 N 4 , SiO x C y (wherein 2x=4y=4), SiO m N n , (wherein 2m+3n=4), SiC x H y (wherein 4x+y=4), TiO 2 , ZrO 2 , Al 2 O 3 or a mixture thereof.
2. The metallic component of claim 1 , wherein the vapor phase process further comprises:
repeating one for more of the above steps as necessary to arrive at an desired film thickness and/or composition.
3. The metallic component of claim 1 , wherein the protective coating comprises two or more layers each comprising a different protective material.
4. The metallic component of claim 1 , wherein the metallic component is made of stainless steel, titanium, or titanium alloy.