TY - JOUR A1 - Geißler, Daniel A1 - Gollwitzer, C. A1 - Sikora, A. A1 - Minelli, C. A1 - Krumrey, M. A1 - Resch-Genger, Ute T1 - Effect of fluorescent staining on size measurements of polymeric nanoparticles using DLS and SAXS N2 - The influence of fluorescence on nanoparticle size measurements using dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) was investigated. For this purpose, two series of 100 nm-sized polymer nanoparticles stained with different concentrations of the fluorescent dyes DY555 and DY680 were prepared, absorbing/emitting at around 560 nm/590 nm and 695 nm/715 nm, respectively. SAXS measurements of these particle series and a corresponding blank control (without dye) revealed similar sizes of all particles within an uncertainty of 1 nm. DLS measurements carried out at three different laboratories using four different DLS instruments and two different laser wavelengths, i.e., 532 nm and 633 nm, revealed also no significant changes in size (intensity-weighted harmonic mean diameter, ZAverage) and size distribution (polydispersity index, PI) within and between the two dye-stained particle series and the blank sample. Nevertheless, a significant decrease of the detected correlation coefficients was observed with increasing dye concentration, due to the increased absorption of the incident light and thus, less coherent light scattering. This effect was wavelength dependent, i.e. only measurable for the dye-stained particles that absorb at the laser wavelength used for the DLS measurements. PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-349684 SN - 1759-9660 SN - 1759-9679 VL - 7 IS - 23 SP - 9785 EP - 9790 PB - RSC Publ. CY - Cambridge AN - OPUS4-34968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rackwitz, Vanessa A1 - Krumrey, M. A1 - Laubis, C. A1 - Scholze, F. A1 - Hodoroaba, Vasile-Dan T1 - New reference and test materials for the characterization of energy dispersive X-ray spectrometers at scanning electron microscopes N2 - Checking the performance of energy dispersive X-ray spectrometers as well as validation of the results obtained with energy dispersive X-ray spectrometry (EDX) at a scanning electron microscope (SEM) involve the use of (certified) reference and dedicated test materials. This paper gives an overview on the test materials mostly employed by SEM/EDX users and accredited laboratories as well as on those recommended in international standards. The new BAM reference material EDS-CRM, which is currently in the process of certification, is specifically designed for the characterization of EDS systems at a SEM through calibration of the spectrometer efficiency in analytical laboratories in a simple manner. The certification of the spectra by means of a reference EDS is described. The focus is on the traceability of EDS efficiency which is ensured by measurements of the absolute detection efficiency of silicon drift detectors (SDD) and Si(Li) detectors at the laboratory of the PTB using the electron storage ring BESSY II as a primary X-ray source standard. A new test material in development at BAM for testing the performance of an EDS in the energy range below 1 keV is also briefly presented. KW - EDX KW - EDS KW - Performance check KW - SEM KW - Test materials KW - Spectrometer efficiency PY - 2015 U6 - https://doi.org/10.1007/s00216-014-8242-5 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 11 SP - 3045 EP - 3053 PB - Springer CY - Berlin AN - OPUS4-33025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roebben, G. A1 - Kestens, V. A1 - Varga, Z. A1 - Charoud-Got, J. A1 - Ramaye, Y. A1 - Gollwitzer, Christian A1 - Bartczak, D. A1 - Geißler, Daniel A1 - Noble, J.E. A1 - Mazoua, S. A1 - Meeus, N. A1 - Corbisier, P. A1 - Palmai, M. A1 - Mihály, J. A1 - Krumrey, M. A1 - Davies, J. A1 - Resch-Genger, Ute A1 - Kumarswami, N. A1 - Minelli, C. A1 - Sikora, A. A1 - Goenaga-Infante, H. T1 - Reference materials and representative test materials to develop nanoparticle characterization methods: the NanoChOp project case N2 - This paper describes the production and characteristics of the nanoparticle test materials prepared for common use in the collaborative research project NanoChOp (Chemical and optical characterization of nanomaterials in biological systems), in casu suspensions of silica nanoparticles and CdSe/CdS/ZnS quantum dots (QDs). This paper is the first to illustrate how to assess whether nanoparticle test materials meet the requirements of a "reference material" (ISO Guide 30, 2015) or rather those of the recently defined category of "representative test material (RTM)" (ISO/TS 16195, 2013). The NanoChOp test materials were investigated with small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and centrifugal liquid sedimentation (CLS) to establish whether they complied with the required monomodal particle size distribution. The presence of impurities, aggregates, agglomerates, and viable microorganisms in the suspensions was investigated with DLS, CLS, optical and electron microscopy and via plating on nutrient agar. Suitability of surface functionalization was investigated with attenuated total reflection Fourier transform infrared spectrometry (ATR-FTIR) and via the capacity of the nanoparticles to be fluorescently labeled or to bind antibodies. Between-unit homogeneity and stability were investigated in terms of particle size and zeta potential. This paper shows that only based on the outcome of a detailed characterization process one can raise the status of a test material to RTM or reference material, and how this status depends on its intended use. KW - Nanoparticle KW - Materials characterization KW - Reference material KW - Analytical quality assurance KW - Metrology PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-349644 SN - 2296-2646 VL - 3 SP - Article 56, 1 EP - 16 PB - Frontiers Media CY - Lausanne AN - OPUS4-34964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -