TY - JOUR A1 - Hennig, Andreas A1 - Hoffmann, Angelika A1 - Borcherding, H. A1 - Thiele, T. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Simple colorimetric method for quantification of surface carboxy groups on polymer particles N2 - We present a novel, simple, and fast colorimetric method to quantify the total number of carboxy groups on polymer microparticle and nanoparticle surfaces. This method exploits that small divalent transition metal cations (M2+ = Ni2+, Co2+, Cd2+) are efficiently bound to these surface functional groups, which allows their extraction by a single centrifugation step. Remaining M2+ in the supernatant is subsequently quantified spectrophotometrically after addition of the metal ion indicator pyrocatechol violet, for which Ni2+ was identified to be the most suitable transition metal cation. We demonstrate that the difference between added and detected M2+ is nicely correlated to the number of surface carboxy groups as determined by conductometry, thereby affording a validated measure for the trueness of this procedure. The variation coefficient of ~5% found in reproducibility studies underlines the potential of this novel method that can find conceivable applications for the characterization of different types of poly(carboxylic acid)-functionalized materials, e.g., for quality control by manufacturers of such materials. KW - Polymer surface KW - Complexometry KW - Quantification KW - Pyrocatechol violet PY - 2011 U6 - https://doi.org/10.1021/ac2007619 SN - 0003-2700 SN - 1520-6882 VL - 83 IS - 12 SP - 4970 EP - 4974 PB - American Chemical Society CY - Washington, DC AN - OPUS4-23892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, Andreas A1 - Hoffmann, Angelika A1 - Borcherding, H. A1 - Thiele, T. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Quantification of surface functional groups on polymer microspheres by supramolecular host-guest interactions N2 - We introduce a method to determine the number of accessible functional groups on a polymer microsphere surface based on the interaction between the macrocyclic host cucurbit[7]uril (CB7) and a guest reacted to the microsphere surface. After centrifugation, CB7 in the supernatant is quantified by addition of a fluorescent dye. The difference between added and detected CB7 affords the number of accessible surface functional groups. KW - Cucurbituril KW - Acridine orange KW - Fluorescence KW - Polymer surface KW - Surface modification KW - Quantification PY - 2011 U6 - https://doi.org/10.1039/c1cc11692d SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x VL - 47 IS - 27 SP - 7842 EP - 7844 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-24034 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -