Patent ID: 9091695
Filing Date: 2015-07-28
Classification: G01N

Abstract:
1. A method for quantifying an analyte in a sample comprising the steps of: (a) providing a sample containing an analyte; (b) chromatographically separating the analyte from other components in the sample using reverse phase liquid chromatography to obtain a chromatographically separated sample comprising the analyte; (c) transferring the chromatographically separated sample directly to a hydrophilic interaction analytical column, wherein the transferring is performed automatically on-line by a heart-cutting, chromato-focusing, or column switching technique; (d) concentrating the analyte in the chromatographically separated sample using hydrophilic interaction liquid chromatography to obtain a chromatographically concentrated sample comprising the analyte, wherein the analyte that is chromatographically separated in step (b) is the same compound that is concentrated in step (d); and (e) analyzing the chromatographically concentrated sample by mass spectrometry to quantify the analyte in the sample.