Reduction processes in the fast atom bombardment mass spectrometry of sulfonyl esters of diazonaphthalenones

Abstract

Orthoquinone diazides, which are widely used in microlithography, have attracted considerable attention, especially in terms of their application in the production of high-contrast resists. Previous electron impact mass spectrometric results have confirmed that the primary fragmentation process of these compounds is the elimination of N, to form an indenoketene ion. This is analogous to the photodecomposition pathway which makes them effective in the lithographic process. Those results also revealed the occurrence of an alternative process, which involves a twohydrogen reduction of the intermediate species formed prior to conversion to the ketene. The present study investigates the behaviour of the orthoquinone diazides when there is an abundance of protons available to form the reduction product. Several different types of diazonaphthalenone sulfonyl esters, ranging in complexity from the monosubstituted phenol esters to disubstituted dihydroxybenzophenones, were examined using fast atom bombardment mass spectrometry. Although reduction was the primary process in the hydrogen-rich matrices, the extent of reduction was characteristic of the particular isomer as well as the matrix used.

Reduction in Desorption Mass Spectrometry: Multiple Protonation on Flavins without Charge Increment.

“…3), 9) Reducing site was located within the isoalloxazine moiety by the fragment ions at m/z 243.2, 244.3, and 245.1 for riboflavin, as shown in Fig. 1b left, of which the pattern of ion peaks is similar to Fig.…”

“…3), 9) These questions may be answered by assuming that electron transfer occurred concomitantly with protonation as in the redox prosthetic groups in biological systems. If so, ine$ciency of thioglycerol as the reducing agent can also be explained, because more acidic thioglycerol is more e$cient protonating agent than glycerol, thus the rate-determining process of electron transfer ( ῌ of FAD were compared within the FAB mode using di#erent matrices, i.e.…”

Improving fast atom bombardment mass spectra: The influence of some controllable parameters on spectral quality

“…These latter reactions are all examples of beam-induced chemical damage, that is, damage resulting from intermolecular interactions with the products of thermal damage (fragments or electrons). In this context, the term "damage" is applied on a molecular scale, rather than with the macroscopic connotation of damage at or near the sample surface, as defined in dry SIMS studies.Important parameters known to affect the extent of beam-induced damage and the abundance of molecular (or quasi-molecular) ions in FAB spectra include the primary beam flux [9-11] and energy [12,13], and the matrix composition [3,[14][15][16][17][18]. Adventitious photons from the FAB gun may also be involved [9].…”

A fast atom bombardment and matrix‐assisted laser desorption/ionization mass spectrometry study of doubly charged porphyrins

“…In this study several commonly used matrices were tested,8 but it was found that the most abundant molecular ion species [M 2+ − H + ] + and [M 2+ + e − ] +· of porphyrin salts were observed either with SGLY or with NBA. The known electron‐ and especially radical‐acceptor properties of NBA9 were found to be important.…”