Nanoelectrospray ionization source

Hop, C.E., Chen, Y., and Yu, L.J., Uniformity of ionization response of structurally diverse analytes using a chip-based nanoelectrospray ionization source, Rapid Commun. Mass Spectrom., 19(21), 3139, 2005. 

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. 

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]. 

Figure 5.39 Modified nanoelectrospray source used to study ionization sampling efficiencies under conditions of total solvent consumption . The inset shows the modified curtain gas and heated laminar flow particle discriminator interface with the nebulizier assisted nano-ESl arrangement. Reproduced from Schneider, Rapid Commun. Mass Spectrom. 20, 1538 (2006), with permission of John Wiley Sons, Ltd.

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