Two-dimensional LC-MS/MS systems

A method for analyzing one or more analytes in a source sample, comprising the steps of:

• (a) extracting the one or more analytes from the source sample with an extraction solvent to obtain an extraction sample;
• (b) applying the extraction sample and a solvent system to a first liquid chromatography (LC) column with an LC pump system, wherein the first LC column is directly connected to a second LC column through a tube with a diverting valve;
• (c) setting the diverting valve to a first position at a first predetermined time such that the solvent effluent from the first LC column is directed to waste;
• (d) setting the diverting valve to a second position at a second predetermined time such that the solvent effluent from the first LC column enters the second LC column for further separation;
• (e) repeating steps (c) and (d) as needed;
• and
• (f) analyzing the chromatographically separated sample obtained from the second LC column,
• wherein the method utilizes only one LC pump system for both LC columns, and
• wherein the extraction solvent is compatible with the solvent system.