Engin Karabudak
Max Planck Society
Analytical chemistryChemistryAnalytical UltracentrifugationDiabetes mellitusMedicine
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Publications 13
#1Engin Karabudak (İzmir Institute of Technology)H-Index: 10
#2Emre H. Brookes (University of Texas Health Science Center at San Antonio)H-Index: 16
Last. Helmut Cölfen (MPG: Max Planck Society)H-Index: 73
view all 11 authors...
1 CitationsSource
#1Engin Karabudak (İzmir Institute of Technology)H-Index: 10
#2Emre H. Brookes (University of Texas Health Science Center at San Antonio)H-Index: 16
Last. Helmut Cölfen (MPG: Max Planck Society)H-Index: 73
view all 11 authors...
We report an unsurpassed solution characterization technique based on analytical ultracentrifugation, which demonstrates exceptional potential for resolving particle sizes in solution with sub-nm resolution. We achieve this improvement in resolution by simultaneously measuring UV/Vis spectra while hydrodynamically separating individual components in the mixture. By equipping an analytical ultracentrifuge with a novel multi-wavelength detector, we are adding a new spectral discovery dimension to ...
12 CitationsSource
#1Johannes WalterH-Index: 14
#2Konrad LöhrH-Index: 1
Last. Helmut CölfenH-Index: 73
view all 8 authors...
The worldwide trend in nanoparticle technology toward increasing complexity must be directly linked to more advanced characterization methods of size, shape and related properties, applicable to many different particle systems in science and technology. Available techniques for nanoparticle characterization are predominantly focused on size characterization. However, simultaneous size and shape characterization is still an unresolved major challenge. We demonstrate that analytical ultracentrifug...
67 CitationsSource
#1Engin KarabudakH-Index: 10
#2Recep KasH-Index: 6
Last. Guido MulH-Index: 45
view all 8 authors...
Attenuated total reflection-infrared (ATR-IR) spectroscopy is increasingly used to characterize solids and liquids as well as (catalytic) chemical conversion. Here we demonstrate that a piece of silicon wafer cut by a dicing machine or cleaved manually can be used as disposable internal reflection element (IRE) without the need for polishing and laborious edge preparation. Technical aspects, fundamental differences, and pros and cons of these novel disposable IREs and commercial IREs are discuss...
18 CitationsSource
#1Engin Karabudak (UT: University of Twente)H-Index: 10
#2Emre Yüce (MESA+ Institute for Nanotechnology)H-Index: 8
Last. Han Gardeniers (UT: University of Twente)H-Index: 20
view all 6 authors...
Photoexcitation and charge carrier thermalization inside semiconductor photocatalysts are two important steps in solar fuel production. Here, photoexcitation and charge carrier thermalization in a silicon wafer are for the first time probed by a novel, yet simple and user-friendly Attenuated Total Reflectance Infrared spectroscopy (ATR-IR) system.
8 CitationsSource
#1Engin KarabudakH-Index: 10
#2Barbara L. MojetH-Index: 1
Last. Han GardeniersH-Index: 20
view all 5 authors...
We present a micromachined silicon attenuated total reflection-infrared (ATR-IR) crystal with integrated nanofluidic glass channels which enables infrared spectroscopic studies with only 71 nL sample volume. Because of the short path length through silicon, the system allows IR spectroscopy down to 1200 cm–1, which covers the typical fingerprint region of most organic compounds. To demonstrate proof-of-principle, the chip was used to study a Knoevenagel condensation reaction between malononitril...
15 CitationsSource
#1Claudia Backes (FAU: University of Erlangen-Nuremberg)H-Index: 30
#2Engin Karabudak (UT: University of Twente)H-Index: 10
Last. Wendel WohllebenH-Index: 40
view all 6 authors...
We report on the extensive characterization of single-walled carbon nanotubes (SWCNTs) dispersed in a variety of surfactants, such as sodium dodecyl benzene sulfonate (SDBS), sodium cholate (SC), and three synthesized perylene-based surfactants, by using differential sedimentation in H2O and D2O. Multidimensional evaluation of the absorption profiles over radius, wavelength, and time allows the determination of the anhydrous specific volumes of the SWCNT–surfactant complexes as well as the conce...
25 CitationsSource
#1Engin KarabudakH-Index: 10
#2Claudia Backes (FAU: University of Erlangen-Nuremberg)H-Index: 30
Last. Wendel WohllebenH-Index: 40
view all 7 authors...
Interacting solutes form mUltiple associates and usually mask each other in ensemble characterization. They are susceptible to preparation artefacts in the single-molecule techniques commonly applied. To overcome the problem of bulk characterization of a single-walled carbon nanotube (CNT) dispersion with a novel surfactant-intercalant mixture, we obtain color movies of fractionation under extreme gravity, such that each colloidal component is characterized independently. We combine the unique f...
12 CitationsSource
#1Engin Karabudak (MPG: Max Planck Society)H-Index: 10
#2Wendel WohllebenH-Index: 40
Last. Helmut Cölfen (MPG: Max Planck Society)H-Index: 73
view all 3 authors...
A multiwavelength UV/vis detector for the analytical ultracentrifuge (MWL-AUC) has been developed recently. In this work, β-carotene–gelatin composite particles are investigated with MWL-AUC. Band centrifugation with a Vinograd cell is used to ensure maximum sample separation. Spectral changes of the system are observed in dependence of the sedimentation coefficient and are attributed to a previously unknown inhomogeneity of the β-carotene chemical composition with both H- and J-aggregates coexi...
20 CitationsSource
#1Helmut Cölfen (MPG: Max Planck Society)H-Index: 73
#2Thomas M. Laue (UNH: University of New Hampshire)H-Index: 34
Last. Borries Demeler (University of Texas System)H-Index: 41
view all 11 authors...
Progress in analytical ultracentrifugation (AUC) has been hindered by obstructions to hardware innovation and by software incompatibility. In this paper, we announce and outline the Open AUC Project. The goals of the Open AUC Project are to stimulate AUC innovation by improving instrumentation, detectors, acquisition and analysis software, and collaborative tools. These improvements are needed for the next generation of AUC-based research. The Open AUC Project combines on-going work from several...
35 CitationsSource