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 been successfully applied to characterize the covalent grafting of N- m- 3- trifluoromethyl. diazirine-3-yl.phenyl.-4-maleimido-butyramide MAD., a reagent used for immobilization of biomolecules on solid surfaces, i.e., diamond 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 PHI-7200 Reflectron, after shipping identically prepared samples to two independent laboratories. The ToF-SIMS spectrum in the negative ion mode exhibits characteristic signals over a large mass range, allowing to compare spectral differences in data acquired in the static SIMS regime with the two spectrometers to differences in experimental parameters, such as detector voltages. Variations in ion beam damage were not fully reproduced by both ToF-SIMS systems, indicating limitations in the comparison of ion beam damage data using two different sets of experimental parameters. This discrepancy could be related to different mass-dependent ion transmissions of the two spectrometers. The results suggest that a model developed in the literature for the interpretation of ion dose-induced polymer damage can be successfully applied to the case of organic molecules covalently attached to a diamond surface. q1999 Elsevier Science B.V. All rights reserved.