Comparison of conventional, narrow-bore and capillary liquid chromatography mass spectrometry for electrospray ionization mass spectrometry: Practical considerations

Electrospray ionization (ESI) is nowadays the most important technique for on-line liquid chromatography/mass spectrometry (LC/MS) coupling, Different ESI probe designs including the microESI and pneumatically assisted ESI (i onspray) interfaces allow the introduction of sample at flow-rates ranging from a fen hundred nl min(-1) to 1-2 ml min(-1). In this paper, an overview of the different LC/ESIMS devices is presented from the point of view of t heir flow compatibility. Several parameters for LC/ESIMS miniaturization an d its effects on sensitivity are considered from the practical point of vie w. Low-flow ESI requires the use of narrow-bore and capillary columns. Samp le preconcentration microdevices are recommended in order to circumvent som e miniaturization drawbacks such as the low. optimum injection volume and t he low column capacity. Some considerations on fused-silica microcolumn and microESI needle construction are also presented. Copyright (C) 1999 John W iley & Sons, Ltd.