Capillary high-performance liquid chromatography/electrospray ion trap time-of-flight mass spectrometry using a novel nanoflow gradient generator

A type of high-performance liquid chromatography (HPLC) based on a novel nanoflow gradient generator (Asymptotic-Trace-10-Port-Valve (AT10PV) nanoGR generator) was developed and coupled with an electrospray ion trap time-of-flight mass spectrometer (ESI-IT-TOF MS). Stability of the nanoflow GR HPLC system was tested at flow rates of 20 and 50 nL/min by using a nanoflow meter. Average flow rates in a 2-h run were 51.2 nL/min with RSD 0.7% and 21.0 nL/min with RSD 1.8%. Repeatability of analysis of the nanoHPLC/ESI-IT-TOF MS system was also tested by injecting 1.0 microL of trypsin digested bovine serum albumin (BSA) (100 fmol) into a monolithic silica-ODS column (30 microm i.d., 150 mm in length) through a packed silica-ODS trapping column (particle size 5 microm, 150 microm i.d., 10 mm in length). At a flow rate of 50 nL/min, the result demonstrated a reasonably good repeatability of peak retention times (RSD: 0.32-1.1%) and base-ion peak areas (RSD: 4.4-6.6%).