Electrospray ionization nanoelectrospray

Juraschek, R. Dulcks,T. Karas, M. Nanoelectrospray—More than just a minimized flow electrospray ionization source. /. Am. Soc. Mass Spectrom. 1999,10,300-308. 

Several innovative ion sources that are based on ESI were developed, including secondary electrospray ionization (SESI), desorption electrospray ionization (DESl) (Figure 4.4), and nanoelectrospray ionization (nESI). These were described in some detail in Chapter 3 in the context of sample introduction techniques and are only briefly discussed here. 

Maziarz, P. E. Ill, Baker, G. A., Mure, J. V., and Wood, T. D. A comparison of electrospray versus nanoelectrospray ionization Fourier transform mass spectrometry for the analysis of synthetic poly(dimethylsiloxane)/poly(ethylene glycol) oligomer blends. Int.. Mass Spectrom., 202, 241, 2000. 

Capillary Electrochromatography-Electrospray Ionization-Mass Spectrometry An Integrated Electrokinetic Analytical Technique, Fig. 6 Image of sheathless nanoelectrospray interface mounted to mass spectrometer (From Ref [10])... 

The peptides generated by proteolysis are separated using reverse-phase HPLC to minimize mass overlap and ionization suppression caused by ion competition in the electrospray source [40]. The optimized LC gradient parameters efficiently separate peptides while minimizing loss of deuterium through back exchange with solvent. Increased sensitivity can be achieved by using capillary HPLC columns and nanoelectrospray methods [47]. 

Nanoelectrospray ionization (nanoESI), also known as nanospray, nanoflow electrospray, and micro-electrospray, is a low flow/high sensitivity approach to ESI. NanoESI15 is a slight variation on ESI such that the spray needle has been made very small and is positioned close to the entrance of the vacuum of the mass spectrometer and the mass analyzer (Figure 6). This greatly reduces required sample amounts allowing nanoliter flow rates and femto-mole sample consumption. The end result is increased efficiency since the flow rates for... 

Electrospray mass spectrometry (ES-MS) Nanoelectrospray ionization mass spectrometry (NanoESl-MS)... 

A variety of strategies for integrating microfluidic devices with nanoelectrospray ionization have been reported. Proteomic sample solutions are pumped through microchannels pneumatically or by electroosmotic flow (EOF) at 100-300 nL/min samples are typically dissolved in low-pH buffers modified with organic solvents suitable for positive mode mass spectrometry, with detection limits in the fmol-amol range. These methods can be broadly classified by how the electrospray is generated, including direct spray from channels spray from mated, conventional tips and spray from microfabricated tips [4-9]. 

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