TY - JOUR A1 - Min, Hyegeun A1 - Girard-Lauriault, Pierre-Luc A1 - Gross, Thomas A1 - Lippitz, Andreas A1 - Dietrich, Paul A1 - Unger, Wolfgang T1 - Ambient-ageing processes in amine self-assembled monolayers on microarray slides as studied by ToF-SIMS with principal component analysis, XPS, and NEXAFS spectroscopy JF - Analytical and bioanalytical chemistry N2 - We investigated the ageing of amine-terminated self-assembled monolayers (amine-SAMs) on different silica substrates due to exposure to different ambient gases, pressures, and/or temperatures using time-of-flight secondary ion mass spectrometry (ToF-SIMS) with principal component analysis and complementary methods of surface analysis as X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS). The goal of this study is to examine the durability of primary amine groups of amine-SAMs stored in a user laboratory prior to being used as supports for biomolecule immobilization and other applications. We prepared amine-SAMs on the native oxides of silicon wafers and glass slides using 3- aminopropyl triethoxysilane, by using optimized conditions such as anhydrous organic solvent and reaction time scale of hours to avoid multilayer growth. Selected commercial amine-SAM slides have been investigated, too. When the amine-SAMs are exposed to air, oxygen incorporation occurs, followed by formation of amide groups. The formation of oxygen species due to ageing was proved by ToFSIMS, XPS, and NEXAFS findings such as CNO- secondary ion emission at m/z 42, observation of the N 1s HNC=O component peak at 400.2–400.3 eV in XPS, and, last but not least, by formation of a π*(HNC=O) resonance at 401 eV in the N K-edge X-ray absorption spectrum. It is concluded that the used multi-method approach comprising complementary ToF-SIMS, XPS, and NEXAFS analyses is well suited for a thorough study of chemical aspects of ageing phenomena of amine-SAM surfaces. KW - Amine-SAM KW - Ageing process KW - ToF-SIMS KW - NEXAFS KW - XPS PY - 2012 DO - https://doi.org/10.1007/s00216-012-5862-5 SN - 1618-2642 SN - 1618-2650 VL - 403 IS - 2 SP - 613 EP - 623 PB - Springer CY - Berlin AN - OPUS4-25829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -