Desorption ionization on silicon

DGE a AC AMS APCI API AP-MALDI APPI ASAP BIRD c CAD CE CF CF-FAB Cl CID cw CZE Da DAPCI DART DC DE DESI DIOS DTIMS EC ECD El ELDI EM ESI ETD eV f FAB FAIMS FD FI FT FTICR two-dimensional gel electrophoresis atto, 10 18 alternating current accelerator mass spectrometry atmospheric pressure chemical ionization atmospheric pressure ionization atmospheric pressure matrix-assisted laser desorption/ionization atmospheric pressure photoionization atmospheric-pressure solids analysis probe blackbody infrared radiative dissociation centi, 10-2 collision-activated dissociation capillary electrophoresis continuous flow continuous flow fast atom bombardment chemical ionization collision-induced dissociation continuous wave capillary zone electrophoresis dalton desorption atmospheric pressure chemical ionization direct analysis in real time direct current delayed extraction desorption electrospray ionization desorption/ionization on silicon drift tube ion mobility spectrometry electrochromatography electron capture dissociation electron ionization electrospray-assisted laser desorption/ionization electron multiplier electrospray ionization electron transfer dissociation electron volt femto, 1CT15 fast atom bombardment field asymmetric waveform ion mobility spectrometry field desorption field ionization Fourier transform Fourier transform ion cyclotron resonance... 

There is a special case of LDI worth mentioning, desorption/ionization on silicon (DIOS) [159, 160], in which analyte compounds are deposited on a surface of etched silicon. With this substrate the mass range can be extended to a few kilodaltons, allowing for analysis of, for example, small peptides without the involvement of a matrix. 

W. G. Lewis, Z. Shen, M. G. Finn, and G. Siuzdak. Desorption/Ionization On Silicon (DIOS) Mass Spectrometry Background and Applications. Int. J. Mass Spectrom., 226(2003) 107-116. 

Go, E. P. Prenni, J. E. Wei, J. Jones, A. Hall, S. C. Witkowska, H. E. Shen, Z. Siuzdak, G. Desorption/ ionization on silicon time-of-flight/ time-of-flight mass spectrometry. 

Siudzak, G. Quantitative analysis with desorption/ionization on silicon... 

Lewis, W.G., Shen, Z., Finn, M.G., Siudzak, G. Desorption/ionization on silicon (DIOS) mass spectrometry background and applications. Int. ]. Mass Spectrom. 2003, 226, 107-116. 

G. A mass spectrometry plate reader monitoring enzyme activity and inhibition with a desorption/ ionization on silicon (DIOS) platform. ChemBioChem 2004, 5, 921-927. 

Huikko, K., Oestman, P., Sauber, C., Mandel, F., Grigoras, K., Franssila, S., Kotiaho, T., and Kostiainen, R. (2003). Feasibility of atmospheric pressure desorption/ionization on silicon mass spectrometry in analysis of drugs. Rapid Commun. Mass Spectrom. 17 1339-1343. 

Wall, D. B., Finch, J. W., and Cohen, S. A. (2004). Comparison of desorption/ionization on silicon (DIOS) time-of-flight and liquid chromatography/tandem mass spectrometry for assaying enzyme-inhibition reactions. Rapid Commun. Mass Spectrom. 18 1482-1486. 

Bhattacharya, S.H., T.J. Raiford, and K.K. Murray. 2002. Infrared laser desorption/ionization on silicon. Anal. Chem. 74 2228-2231. 

Liu Q, Guo Z, He L (2007) Mass spectrometry imaging of small molecules using desorption/ ionization on silicon. Anal Chem 79 3535-3541. doi 10.1021/ac0611465... 

A continuous improvement has allowed analysis to reach detection limits at the pico-, femto- and attomole levels [72,73], Furthermore, the direct coupling of chromatographic techniques with mass spectrometry has improved these limits to the atto- and zeptomole levels [74,75], A sensitivity record obtained by mass spectrometry has been demonstrated by using modified desorption/ionization on silicon DIOS method to measure concentration of a peptide in solution. This technique has achieved a lower detection limit of 800 yoctomoles, which corresponds to about 480 molecules [76]. 

Matrix-free direct laser desorption ionization of analyte has been studied on different kinds of surfaces without real success because degradation of the sample is usually observed. However, good results were obtained with the method called surface-activated laser desorption ionization (SALDI) [43] which uses graphite as the surface. But the use of porous silicon as a new surface is more promising and has led to the development of a new method called desorption ionization on silicon (DIOS) [44], Unlike the other matrix-free laser desorption ionization methods, DIOS allows ion formation from analyte with little or no degradation. 

Thomas JJ, Shen Z, Crowell JE, Finn MG, Siuzdak G (2001) Desorption/ionization on silicon (DIOS) a diverse mass spectrometry platform for protein characterization. Proc Natl Acad Sci 98 4932-4937... 

Matrix-assisted laser desorption/ionization, desorption ionization on silicone, and desorption electrospray ionization... 

Desorption/ionization on silicon. Another matrix-free approach for the analysis of small molecules is to use modified porous silicon surfaces [61]. A separate name, desorption/ionization on silicon (DIOS), has been coined for this technique [62]. In this approach, the sample is dispensed directly onto a modified porous silicon surface (e.g., silylated porous silicon) and laser-desorbed from the surface. The silicon surface is prepared from flat crystalline silicon by galvanostatic etching. 

Go EP, Prenni JE, Wei J, Jones A, Hall SC, Witkowska HE, Shen Z, Siuzdak G. Desorption/ionization on silicon time-of-flight/time-of-flight mass spectrometry. Anal Chem 2003 75(10) 2504-2506. 

When discussing matrix-free LDI strategies, we should also mention one more related approach that resonated in the specialist literature over the past two decades. In desorption/ ionization on silicon (DIOS), a nanostructured silicon chip is utilized as the SALDI-assisting material [81]. After depositing sample solution on such a chip, the sample is ready for LDI-MS analysis. Furthermore, DIOS chips are compatible with microfluidic and microreactor systems [92, 93]. Thus, DIOS-MS has occasionally been implemented in TRMS-related measurements (see also Chapters 7 and 13). 

Nichols, K.P., Azoz, S., Gardeniers, H.J.G.E. (2008) Enzyme Kinetics by Directly Imaging a Porous Silicon Microfluidic Reactor Using Desorption/Ionization on Silicon Mass Spectrometry. (2008) Anal. Chem. 80 8314-8319. 

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