Nanoflow gradient generator for capillary high-performance liquid chromatography-nanoelectrospray mass spectrometry.

ABSTRACT

A novel nanoflow gradient generator using a 10-port switching valve with two injection loops installed, which is referred to here as the "Asymptotic-Trace-10-Port-Valve" (AT10PV) nanoGR generator, has been applied to capillary high-performance liquid chromatography (HPLC)-microelectrospray (microESI) or nanoelectrospray (nanoESI) time-of-flight mass spectrometry (TOF MS). In this study, performance of this capillary HPLC-micro/nanoESI-MS system was tested at a flow rate of 200 nl/min by using three typical peptides (angiotensins I, II, and III 50 fmol each). The result demonstrated that this system provides reasonably good repeatability of peak retention times (R. S.D. of less than 0.5%). Sequential runs of a series of sample injections were performed in the same manner as conventional analysis at microflow rates.