Round robin of time-of-flight secondary ion mass spectrometry damage studies of a photoimmobilized reagent on diamond surfaces designed for surface glycoengineering

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) has previously be en successfully applied to characterize the covalent grafting of N-(m-(3-(t rifluoromethyl) diazirine-3-yl)phenyl)-4-maleimido-butyramide (MAD), a reag ent used for immobilization of biomolecules on solid surfaces, i.e., diamon d substrates. In this study, the molecule was used to compare dose-related damage data obtained on two different ToF-SIMS systems, a PHI Trift and a P HI-7200 Reflectron, after shipping identically prepared samples to two inde pendent laboratories. The ToF-SIMS spectrum in the negative ion mode exhibi ts characteristic signals over a large mass range, allowing to compare spec tral differences in data acquired in the static SIMS regime with the two sp ectrometers to differences in experimental parameters, such as detector vol tages. Variations in ion beam damage were not fully reproduced by both ToF- SIMS systems, indicating limitations in the comparison of ion beam damage d ata using two different sets of experimental parameters. This discrepancy c ould be related to different mass-dependent ion transmissions of the two sp ectrometers. The results suggest that a model developed in the Literature f or the interpretation of ion dose-induced polymer damage can be successfull y applied to the case of organic molecules covalently attached to a diamond surface. (C) 1999 Elsevier Science B.V. All rights reserved.