TY - JOUR A1 - Gross, Thomas A1 - Pippig, F. A1 - Merz, B. A1 - Merz, R. A1 - Vohrer, U. A1 - Mix, Renate A1 - Steffen, H. A1 - Bremser, Wolfram A1 - Unger, Wolfgang T1 - Determination of OH groups at plasma oxidised poly(propylene) by TFAA chemical derivatisation XPS: an inter-laboratory comparison N2 - A first inter-laboratory comparison was conducted to demonstrate and document the capability of interested laboratories to measure the fraction of C—OH species on a plasma oxidised poly(propylene) sample by using a chemical derivatisation XPS approach. This report presents the results from that inter-laboratory comparison and includes the data received for the measured values and their associated standard deviations of laboratory means, at a 95% confidence level. The measurements were guided by a protocol developed within the group before and summarised shortly in the paper. Standard deviations that may characterise the state-of-the-art for the nominally simple and rather often practised case of TFAA chemical derivatisation XPS of C—OH species on a plasma oxidised polyolefin surface are calculated following ISO 5725-2:1994. The main conclusion is that the associated degree of equivalence reached by the participating laboratories in this comparison is still low. Further research to improve chemical derivatisation XPS protocols is mandatory. KW - Chemical derivatisation KW - ESCA/XPS KW - Inter-laboratory comparison KW - Photoelectron spectroscopy (PES) KW - Poly(propylene) (PP) PY - 2010 DO - https://doi.org/10.1002/ppap.200900142 SN - 1612-8850 SN - 1612-8869 VL - 7 IS - 6 SP - 494 EP - 503 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-21678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graf, Nora A1 - Lippitz, Andreas A1 - Gross, Thomas A1 - Pippig, F. A1 - Holländer, A. A1 - Unger, Wolfgang T1 - Determination of accessible amino groups on surfaces by chemical derivatization with 3,5-bis(trifluoromethyl)phenyl isothiocyanate and XPS/NEXAFS analysis N2 - The determination of amino groups on surfaces capable of binding biomolecules is important for the understanding and optimization of technologically relevant coupling processes. In this study, three different types of amino-functionalized model surfaces, amino thiolate on Au, amino siloxane on Si, and polyethylene (PE) foils and films reacted with 1,2-diaminoethane (DAE) were derivatized with 3,5-bis(trifluoromethyl)phenyl isothiocyanate. Subsequently, these samples were analyzed by chemical derivatization X-ray photoelectron spectroscopy (CD-XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The determination of amino groups by this analytical approach allows gaining insight into the availability of groups on surfaces that can actually serve as attachment sites for biomolecules in technical applications. In the case of the amino thiolate on Au, almost 90% of the expected amino groups were detected by CD-XPS. Investigation of the amino siloxane films revealed lower yields for the derivatization reaction in the order of 30%. The lowered reaction yields are thought to be due to interactions between the amino siloxane`s amino and silanol groups or the underlying substrate, making them inaccessible to the derivatization agent. The aminated PE samples are characterized by a complex surface chemistry and structure, and reaction yields of the derivatization reaction cannot be unequivocally derived. However, 1-3% of the total carbon atoms in the surface layer were found to be bound to amino groups accessible to the derivatization agent. It can be concluded that, depending on the detailed character of the investigated amino-terminated surface, the amount of amino groups accessible to CD-XPS can be substantially lower than the total amount of amino groups present at the surface. KW - XPS/ESCA KW - NEXAFS/XANES KW - CD-XPS KW - Amino-functionalized surfaces KW - SAM PY - 2010 DO - https://doi.org/10.1007/s00216-009-3233-7 SN - 1618-2642 SN - 1618-2650 VL - 396 IS - 2 SP - 725 EP - 738 PB - Springer CY - Berlin AN - OPUS4-20744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -