Nano-electrospray

Example The reduced sample consumption of nanoESI allows for the sequencing of the peptides (Chap. 9.4.7) obtained by tryptic digestion of only 800 fmol of the protein bovine semm albumin (BSA, Fig. 11.6). [66] The experiment depicted below requires each of the BSA-derived peptide ions in the full scan spectrum to be subjected to fragment ion analysis by means of CID-MS/MS on a triple quadrupole instmment (Chaps. 2.12 and 4.4.5). 

Note Besides its low sample consumption, nanoESI is free of memory effects because each sample is supplied in a fresh capillary by means of disposable micropipettes. Furthermore, the narrow exits of nanoESI capillaries prevent air-sensitive samples from rapid decomposition. 

The sample throughput of nanoESI is limited by the comparatively time-consuming procedure of manual capillary loading. A chip-based nanoESI sprayer on an etched silicon wafer allows for the automated loading of the sprayer array by a pipetting robot (Fig. 11.7). The chip provides a 10 x 10 array of nanoESI 

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ESI-MS is the most successful method of coupling a condensed phase separation technique to a mass spectrometer. Because the input to ESI is a liquid, electrospray serves as an interface between the mass spectrometer and liquid chromatographic techniques, including SEC and CE (capillary electrophoresis). In LC-MS the flow-rate should lie in the range recommended for the HPLC pump and the mass spectrometer (typically 0.001 -l.OmLmin-1). Recent advances in (nano)electrospray technology include the development of the use of very low solvent flow-rates (30 to 1000nLmin-1) [130,131],... 

ESI and APCI are soft ionisation techniques which usually result in quasi-molecular ions such as [M + H]+ with little or no fragmentation molecular weight information can easily be obtained. However, experimental conditions can also be chosen in such a way that a sufficiently characteristic pattern is obtained, allowing verification [540]. ESI is amenable to thermally labile and nonvolatile molecules. Both ESI and APCI are much more sensitive than PB and very well suited for quantitative analysis, but less so for unknown samples. The choice among the two is usually determined by the application. Recently, nanoscale LC-ESI-MS has been developed [541]. The nano-electrospray ion source offers the highest sensitivity available for LC-MS (atto-to femtomole range) and can also be used as an off-line ion source. 

Qi, L. and Danielson, N.D. 2005. Quantitative determination of pharmaceuticals using nano-electrospray ionization mass spectrometry after reversed phase mini-solid phase extraction. J. Pharm. 

M. Wilm, A. Shevchenko, T. Houthaeve, S. Breit, L. Schweigerer, T. Fotsis, and M. Mann. Femtomole Sequencing of Proteins from Polyacrylamide Gels by Nano-Electrospray Mass Spectrometry. Nature, 379(1996) 466-469. 

M. Karas, U. Bahr, and T. Dulcks. Nano-Electrospray Ionization Mass Spectrometry Addressing Analytical Problems beyond Routine. Fresenius. J. Anal. Chem., 366(2000) 669-676. 

Fig. 11.5. Nano-electrospray (a) SEM micrograph of the open end of a glass nanoESI capillary having a 2-pm aperture, (b) microscopic view of the spray from a nanoESI capillary as provided by observations optics. By courtesy of New Objective, Woburn, MA.

Numerous workers have demonstrated the applicability of electrospray ionization mass spectrometry (ESI/MS) for the detection and analysis of biomolecules with highly electronegative groups (reviewed by Wood et al., 2003, and for neutral steroids by Higashi and Shimada, 2004). The sensitivity of detection of neurosteroids can also be enhanced by derivatization when they are analyzed by nano-electrospray/mass spectrometry procedures. Neurosteroid sulfates can be easily prepared in a single-step reaction in pyridine with the N,N-dimethylformamide complex of sulfur trioxide (Chatman et al., 1999). Another elegant... 

Liu S, Sjovall J, Griffiths WJ. 2000. Analysis of oxosteroids by nano-electrospray mass spectrometry of their oximes. Rapid Commun Mass Spectrom 14 390-400. 

Alexander, J. N., Schultz, G. A., and Polll, J. B. (1998). Development of a nano-electrospray mass spectrometry source for nanoscale liquid chromatography and sheathless capillary electrophoresis. Rapid Commun. Mass Spectrom. 12, 1187—1191. 

Wilm, M., Shevchenko, A., Houthaeve, T., Breit, S., Schweigerer, L., Fotsis, T., and Mann, M. (1996) Femtomole sequencing of proteins from polyacrylamide gels by nano electrospray mass spectrometry. Nature 379 466—469. 

Cuyckens, F. et al., Structure characterization of flavonoid 0-diglycosides by positive and negative nano-electrospray ionization ion trap mass spectrometry, J. Mass Spectrom., 36, 1203, 2001. 

Prinz, H. Lavie, A. Scheidig, A.J. Spangenberg, O. Konrad, M. Binding of nucleotides to guanylate kinase, p21(ras), and nucleoside-diphosphate kinase studied by nano-electrospray mass spectrometry. J. Biol. Chem., 274, 35337-35342 (1999)... 

A. Pfenninger, M. Karas, B. Finke, and B. Stahl, Structural analysis of underivatized neutral human milk oligosaccharides in the negative ion mode by nano-electrospray MSn (Part 2 Application to isomeric mixtures), J. Am. Soc. Mass Spectrom., 13 (2002) 1341-1348. 

B. Macek, J. Hofsteenge, and J. Peter-Katalinic, Direct determination of glycosylation sites in O-fucosylated glycopeptides using nano-electrospray quadrupole time-of-flight mass spectrometry, Rapid Commun. Mass Spectrom., 15 (2001) 771-777. 

Carte, N., Cavusoglu, N., Leize, E., Van Dorsselaer, A., Charlet, M and Bulet, P. (2001) De novo sequencing by nano-electrospray multiple-stage tandem mass spectrometry of an immune-induced peptide of Drosophila melanogaster. Eur. J. Mass Spectrom. 7(4), 399 108. 

M. Sawada et al., Depression of the apparent chiral recognition ability obtained in the host-guest complexation systems by electrospray and nano-electrospray ionization mass spectrometry. Eur. J. Mass Spectrom. 10, 27-37 (2004)... 

Fig. 2. Advion s ESI Chip is an array of 100 independent nano electrospray nozzles etched in silicon. Image 1 the 10x10 array ESI Chip (chip dimensions=3.9x3.9 cm). Image 2 magnification of 10x10 array. Image 3 magnification on one nanoelectrospray device. Image 4 magnification on one nano electrospray nozzle. Reprinted with permission from Advion Bio-Sciences, Inc...

Mann, M. (1996). Femtomole sequencing of proteins from polyacrylamide gels by nano-electrospray mass spectrometry. Nature 379, 466-469. 

Figure 9.2 Photographs of several mass spectrometers (a) electrospray ion-trap, (b) matrix-assisted laser desorption/ionization-time-of-flight and (c) nano-electrospray quadrupole-time-of-flight.

Desorption nano-electrospray (nano-DESI) has also been tested for qualitative analysis of anthocyanins in wine samples (Table 5.1 Method 5) (Hartmanova et ah, 2010). Acidifying of the samples and providing an acidic spray liquid (methanol/water 75 25 with 0.2% HCOOH) were essential for obtaining good quality spectra. From the nano-DESI-MS data, the ratio of two grape cultivars (Neronet and Rubinet) in a mixture could be determined. Detection of the main anthocyanins in slices of wine grapes, chokeberries, and elderberries or in a wine stain on cotton fabric was also possible (Hartmanova et al., 2010). 

In Table 5.1, a number of different conditions are presented for the separation and quantitation of anthocyanins. For simple profiles, the gradient profile is not critical as separations can be achieved relatively easy (Table 5.1 Methods 1-3). However, for samples such as blueberry and Concord grape, which contain complex mixtures with 15 or more anthocyanins or with several acylated anthocyanins, the gradient needed to get resolution can be more complex (Table 5.1 Method 4). Wine samples also fall into this category. Desorption nano-electrospray ionization mass spectrometry has been used to solve some of the resolution and identification issues (Table 5.1 Method 5). However, issues related to quantitation have not been dealt with in this method. 

Hartmanova, L. Ranc, V. Papouskova, B. Bednar, P. Havlicek, V. Lemr, K. 2010. Fast profiling of anthocyanins in wine by desorption nano-electrospray ionization mass spectrometry. J. Chromatogr. A. 1217 4223 228. 

Brtigger B, Erben G, Sandhoff R, Wieland FT, Lehmann WD. Quantitative analysis of biological membrane lipids at the low picomole level by nano electrospray ionization tandem mass spectrometry. Proc. Natl. Acad. Sci. U.S.A. 1997 94 2339-2344. 

Nano-electrospray Mass Spectrometry and Edman Sequencing of Peptides and Proteins Collected from Capillary Electrophoresis... 

Nano-electrospray MS and Edman Sequencing Using CE E. Edman Sequencing... 

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