1
|
Boldrini B, Ostertag E, Rebner K, Oelkrug D. Exploring the hidden depth by confocal Raman experiments with variable objective aperture and magnification. Anal Bioanal Chem 2021; 413:7093-7106. [PMID: 34599394 PMCID: PMC8589783 DOI: 10.1007/s00216-021-03678-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/25/2021] [Accepted: 09/20/2021] [Indexed: 10/31/2022]
Abstract
The article analyzes experimentally and theoretically the influence of microscope parameters on the pinhole-assisted Raman depth profiles in uniform and composite refractive media. The main objective is the reliable mapping of deep sample regions. The easiest to interpret results are found with low magnification, low aperture, and small pinholes. Here, the intensities and shapes of the Raman signals are independent of the location of the emitter relative to the sample surface. Theoretically, the results can be well described with a simple analytical equation containing the axial depth resolution of the microscope and the position of the emitter. The lower determinable object size is limited to 2-4 μm. If sub-micrometer resolution is desired, high magnification, mostly combined with high aperture, becomes necessary. The signal intensities and shapes depend now in refractive media on the position relative to the sample surface. This aspect is investigated on a number of uniform and stacked polymer layers, 2-160 μm thick, with the best available transparency. The experimental depth profiles are numerically fitted with excellent accuracy by inserting a Gaussian excitation beam of variable waist and fill fraction through the focusing lens area, and by treating the Raman emission with geometric optics as spontaneous isotropic process through the lens and the variable pinhole, respectively. The intersectional area of these two solid angles yields the leading factor in understanding confocal (pinhole-assisted) Raman depth profiles. Spearfishing is a well-known example of the effects of refraction at the boundary between two index-mismatched media. The object Greal is seen, due to refraction, as Gvir from the angle β (without knowing the depth position). The real position is obtained under the angle α. In a microscope (see inset), index mismatch deforms the image point of Greal into an image line. The pinhole substantially reduces deformations and allows the determination of the position of the point emitter G. (Cartoon designed by Sofia Anker).
Collapse
Affiliation(s)
- Barbara Boldrini
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany.
| | - Edwin Ostertag
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany
| | - Karsten Rebner
- Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany
| | - Dieter Oelkrug
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
| |
Collapse
|
2
|
Ostertag E, Scholz M, Klein J, Rebner K, Oelkrug D. Pigmentation of White, Brown, and Green Chicken Eggshells Analyzed by Reflectance, Transmittance, and Fluorescence Spectroscopy. ChemistryOpen 2019; 8:1084-1093. [PMID: 31406655 PMCID: PMC6682939 DOI: 10.1002/open.201900154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/24/2019] [Indexed: 12/19/2022] Open
Abstract
We report on the reflectance, transmittance and fluorescence spectra (λ=200-1200 nm) of four types of chicken eggshells (white, brown, light green, dark green) measured in situ without pretreatment and after ablation of 20-100 μm of the outer shell regions. The color pigment protoporphyrin IX (PPIX) is embedded in the protein phase of all four shell types as highly fluorescent monomers, in the white and light green shells additionally as non-fluorescent dimers, and in the brown and dark green shells mainly as non-fluorescent poly-aggregates. The green shell colors are formed from an approximately equimolar mixture of PPIX and biliverdin. The axial distribution of protein and colorpigments were evaluated from the combined reflectances of both the outer and inner shell surfaces, as well as from the transmittances. For the data generation we used the radiative transfer model in the random walk and Kubelka-Munk approaches.
Collapse
Affiliation(s)
- Edwin Ostertag
- Process Analysis and Technology (PA&T)Reutlingen UniversityAlteburgstr. 15072762ReutlingenGermany
| | - Miriam Scholz
- Process Analysis and Technology (PA&T)Reutlingen UniversityAlteburgstr. 15072762ReutlingenGermany
| | - Julia Klein
- Process Analysis and Technology (PA&T)Reutlingen UniversityAlteburgstr. 15072762ReutlingenGermany
| | - Karsten Rebner
- Process Analysis and Technology (PA&T)Reutlingen UniversityAlteburgstr. 15072762ReutlingenGermany
| | - Dieter Oelkrug
- Institute of Physical and Theoretical ChemistryUniversity of TübingenAuf der Morgenstelle 1872076TübingenGermany
| |
Collapse
|
3
|
Oelkrug D, Boldrini B, Rebner K. Comparative Raman study of transparent and turbid materials: models and experiments in the remote sensing mode. Anal Bioanal Chem 2016; 409:673-681. [DOI: 10.1007/s00216-016-9582-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/11/2016] [Accepted: 04/19/2016] [Indexed: 11/30/2022]
|
4
|
Strähle J, Hiller W, Eitel E, Oelkrug D. Die Strukturchemie der Kupfer(I)Halogenid-Lewisbase Addukte. Z KRIST-CRYST MATER 2015. [DOI: 10.1524/zkri.1980.153.14.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
5
|
Abstract
Abstract
The absorption and fluorescence of three isomeric distyrylbenzenes are investigated as function of temperature. From the fluorescence decay times and fluorescence quantum yields two classes of oligostyrylarenes can be distinguished. A decisive criterion for this classification is, whether the first excited singlet state S1 belongs to an allowed or forbidden transition S0→S1.
Collapse
Affiliation(s)
- Dieter Oelkrug
- Institut für Physikalische und Theoretische Chemie der Universität Tübingen
| | - Klaus Rempfer
- Institut für Physikalische und Theoretische Chemie der Universität Tübingen
| | - Ellen Prass
- Institut für Organische Chemie der Universität Mainz
| | - Herbert Meier
- Institut für Organische Chemie der Universität Mainz
| |
Collapse
|
6
|
Radjaipour M, Oelkrug D. Kinetik der Lumineszenz-Thermochromie und Zuordnung der Tieftemperaturemission von Pyridino-Kupfer(I)-jodid. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/bbpc.197800004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
7
|
Oelkrug D, Reich S, Specht M, Stauch H. Light Scattering and Lateral Resolved Reflection Spectroscopy on Electrochemically Reacting Electrodes. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/bbpc.198800316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
8
|
Oelkrug D, Brun M, Hubner P, Rebner K, Boldrini B, Kessler R. Penetration of light into multiple scattering media: model calculations and reflectance experiments. Part II: The radial transfer. Appl Spectrosc 2013; 67:385-395. [PMID: 23601538 DOI: 10.1366/12-06800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In continuation of our contribution to "The Axial Transfer" (Appl. Spectr. 2012. 66(8): 934-943), this paper describes the distribution of localized incident radiation in multiple scattering layers of arbitrary thickness and analyzes the lateral intensity profiles of radiation leaving the sample from its illuminated and non-illuminated surfaces. The theoretical profiles are calculated with different approximations of the equation of transfer. We derive for both non-absorbing and absorbing layers simple analytical expressions and verify their accuracy and range of applicability by comparison with Monte Carlo simulations. Particular emphasis is given to the analysis of the radial absorption, an under-theorized and under-investigated feature that can help to identify weak or hidden absorbers. In addition, we contribute to the description of how the radial reflectance is affected by anisotropy or by error sources like multiple surface reflection for samples in glass cells or deflectance (sideway loss) of radiation in small samples. Finally, the theoretical results are compared with experimental data of radial reflectance for quasi non-absorbing and absorbing powder layers.
Collapse
Affiliation(s)
- Dieter Oelkrug
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | | | | | | | | | | |
Collapse
|
9
|
Oelkrug D, Ostertag E, Kessler RW. Quantitative Raman spectroscopy in turbid matter: reflection or transmission mode? Anal Bioanal Chem 2013; 405:3367-79. [DOI: 10.1007/s00216-013-6719-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/29/2012] [Accepted: 01/10/2013] [Indexed: 11/30/2022]
|
10
|
Oelkrug D, Brun M, Rebner K, Boldrini B, Kessler R. Penetration of light into multiple scattering media: model calculations and reflectance experiments. Part I: the axial transfer. Appl Spectrosc 2012; 66:934-943. [PMID: 22800964 DOI: 10.1366/11-06518] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The article presents two general equations of radiation penetration into layers of diffuse reflectors. One of the equations describes the depth origins of reflection, the other the depth profiles of absorption. The equations are evaluated within the theory of radiative transfer applying various degrees of analytical approximations and Monte Carlo simulations. The data are presented for different scattering and absorption coefficients, arbitrary layer thicknesses, collimated and diffused irradiation, and anisotropic forward scattering. The calculated mean depths of reflection are always lower than the mean depths of absorption. For nearly non-absorbing layers, the mean depths of absorption are about one third of the physical layer thickness. In contrast, penetration saturates for strong absorbers at very low depth levels. From the simulated data, methods are derived for the determination of the penetration depth from reflectance and transmittance data of thin layers or from radially diffused reflectance profiles upon spot irradiation. The methods are experimentally verified for a series of metal oxide powders with particle sizes ranging from much smaller to much larger than the wavelength of irradiation and for microcrystalline cellulose stained with different concentrations of an organic dye.
Collapse
Affiliation(s)
- Dieter Oelkrug
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | | | | | | | | |
Collapse
|
11
|
|
12
|
|
13
|
Elsherbiny AS, Egelhaaf HJ, Oelkrug D. Accessibility and shielding of silanol surface centers on porous silica beads; UV/vis absorption and fluorescence studies. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
14
|
Kessler R, Krabichler G, Uhl S, Oelkrug D, Hagan W, Hyslop J, Wilkinson F. Transient Decay Following Pulse Excitation of Diffuse Scattering Samples. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/713821340] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- R.W. Kessler
- a Institut für Physikalische und Theoretische Chemie der Universität, D-7400 Tubingen, F.R. Germany
| | - G. Krabichler
- a Institut für Physikalische und Theoretische Chemie der Universität, D-7400 Tubingen, F.R. Germany
| | - S. Uhl
- a Institut für Physikalische und Theoretische Chemie der Universität, D-7400 Tubingen, F.R. Germany
| | - D. Oelkrug
- a Institut für Physikalische und Theoretische Chemie der Universität, D-7400 Tubingen, F.R. Germany
| | - W.P. Hagan
- b Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire LE11 3TU, England
| | - J. Hyslop
- b Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire LE11 3TU, England
| | - F. Wilkinson
- b Department of Chemistry, Loughborough University of Technology, Loughborough, Leicestershire LE11 3TU, England
| |
Collapse
|
15
|
Oelkrug D, Wölpl A, Kempny W, Kayser W. Lumineszenz und Struktur der Mangan(II)-halogenide. II. Mechanismen der Konzentrations- und Fremdionenlöschung in MnCl2 und im Mischkristall MnCl2/CdCl2. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19760800510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
16
|
|
17
|
Oelkrug D, Kempny W. Lumineszenz und Struktur der Mangan(II)-halogenide. I. Quantenausbeuten und Abklingzeiten in Systemen mit unverknüpften Koordinationspolyedern. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19760800509] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
18
|
Rebner K, Schmitz M, Boldrini B, Kienle A, Oelkrug D, Kessler RW. Dark-field scattering microscopy for spectral characterization of polystyrene aggregates. Opt Express 2010; 18:3116-3127. [PMID: 20174146 DOI: 10.1364/oe.18.003116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Light scattering measurements of particle aggregates contain complex information which is difficult to decrypt. Dark-field scattering microscopy in the visible range is used to characterize multi-arranged polystyrene beads. First, measured light scattering spectra of single spheres are compared with the Mie theory. Then, additional spectral measurements of three different sample sets of sphere aggregates are carried out. The aggregates consist of homogeneous spheres and differ in number of spheres, arrangement and contact area. Principal component analysis is used to reduce the number of variables and achieve an accurate classification regarding the aggregate characteristics.
Collapse
Affiliation(s)
- Karsten Rebner
- Department of Process Analytics, Reutlingen Research Institute, Alteburgstr. 150, D-72762 Reutlingen, Germany
| | | | | | | | | | | |
Collapse
|
19
|
Kessler W, Oelkrug D, Kessler R. Using scattering and absorption spectra as MCR-hard model constraints for diffuse reflectance measurements of tablets. Anal Chim Acta 2009; 642:127-34. [DOI: 10.1016/j.aca.2009.01.057] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 12/18/2008] [Accepted: 01/29/2009] [Indexed: 11/26/2022]
|
20
|
Srinivasan G, Villanueva-Garibay JA, Müller K, Oelkrug D, Milian Medina B, Beljonne D, Cornil J, Wykes M, Viani L, Gierschner J, Martinez-Alvarez R, Jazdzyk M, Hanack M, Egelhaaf HJ. Dynamics of guest molecules in PHTP inclusion compounds as probed by solid-state NMR and fluorescence spectroscopy. Phys Chem Chem Phys 2009; 11:4996-5009. [DOI: 10.1039/b820604j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
Sancho-García JC, Brédas JL, Beljonne D, Cornil J, Martínez-Alvarez R, Hanack M, Poulsen L, Gierschner J, Mack HG, Egelhaaf HJ, Oelkrug D. Design of π-Conjugated Organic Materials for One-Dimensional Energy Transport in Nanochannels. J Phys Chem B 2005; 109:4872-80. [PMID: 16863141 DOI: 10.1021/jp045364i] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Various end-substituted distyrylbenzenes have been synthesized to serve as guest molecules in inclusion compounds to promote efficient energy transport along one-dimensional channels. Their optical and photophysical properties have been characterized at both experimental and theoretical levels. All molecules display a large transition dipole moment between the ground state and lowest excited state and hence a short radiative lifetime (on the order of 1-2 ns). They also exhibit a large spectral overlap between the emission and absorption spectra, which enables efficient energy transport between molecules arranged in a head-to-tail configuration in nanochannels. Hopping rates on the order of 10(12) s(-1) are calculated at a full quantum-chemical level; this is much larger than the radiative lifetimes and opens the way for energy migration over large distances. Changes in the nature of the terminal substituents are found to modulate the optical properties weakly but to impact significantly the energy transfer rates.
Collapse
Affiliation(s)
- Juan Carlos Sancho-García
- Laboratory for Chemistry of Novel Materials, Center for Research in Molecular Electronics and Photonics, University of Mons-Hainaut, Place du Parc 20, B-7000 Mons, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Affiliation(s)
- Johannes Gierschner
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany, and FG Physical Chemistry, Institute of Chemistry, University of Hohenheim, 70593 Stuttgart, Germany
| | - Hans-Georg Mack
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany, and FG Physical Chemistry, Institute of Chemistry, University of Hohenheim, 70593 Stuttgart, Germany
| | - Dieter Oelkrug
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany, and FG Physical Chemistry, Institute of Chemistry, University of Hohenheim, 70593 Stuttgart, Germany
| | - Isabella Waldner
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany, and FG Physical Chemistry, Institute of Chemistry, University of Hohenheim, 70593 Stuttgart, Germany
| | - Hermann Rau
- Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany, and FG Physical Chemistry, Institute of Chemistry, University of Hohenheim, 70593 Stuttgart, Germany
| |
Collapse
|
23
|
Oelkrug D, Uhl S, Wilkinson F, Willsher CJ. Bonding and mobility of acridine on some metal oxide surfaces as studied by delayed fluorescence and transient absorption spectroscopy. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100348a032] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
24
|
Oelkrug D, Reich S, Wilkinson F, Leicester PA. Photoionization on insulator surfaces: diffuse reflectance laser flash photolysis of distyrylbenzenes adsorbed on silica and alumina. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100154a051] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
Waluk J, Herbich J, Oelkrug D, Uhl S. Excited-state double proton transfer in the solid state: the dimers of 1-azacarbazole. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100408a002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
26
|
Oelkrug D, Krabichler G, Honnen W, Wilkinson F, Willsher CJ. Photophysical behavior of diphenylpolyenes adsorbed on alumina by diffuse reflectance laser flash photolysis. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100323a053] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
27
|
Honnen W, Krabichler G, Uhl S, Oelkrug D. Room-temperature phosphorescence and delayed charge-transfer fluorescence of coronene adsorbed on .gamma.-alumina. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j150642a022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
28
|
Guenther R, Oelkrug D, Rettig W. Luminescence studies on the internal mobility of adsorbed molecules: 4-(N,N-dimethylamino)benzonitrile and related compounds. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100134a021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
29
|
Gierschner J, Mack HG, Lüer L, Oelkrug D. Fluorescence and absorption spectra of oligophenylenevinylenes: Vibronic coupling, band shapes, and solvatochromism. J Chem Phys 2002. [DOI: 10.1063/1.1469612] [Citation(s) in RCA: 252] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
30
|
|
31
|
Schweikart KH, Hanack M, Lüer L, Oelkrug D. Synthesis, Absorption and Luminescence of a New Series of Soluble Distyrylbenzenes Featuring Cyano Substituents at the Peripheral Rings. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200101)2001:2<293::aid-ejoc293>3.0.co;2-n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
32
|
Egelhaaf HJ, Holder E, Herman P, Mayer HA, Oelkrug D, Lindner E. Synthesis, characterisation, and fluorescence spectroscopic mobility studies of fluorene labeled inorganic–organic hybrid polymers. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b102088i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
33
|
Martinez-Ruiz P, Behnisch B, Schweikart KH, Hanack M, Luer L, Oelkrug D. Tuning of photo- and electroluminescence of new soluble, PPV-analogous short-chain compounds with naphthalene moieties. Chemistry 2000; 6:1294-301. [PMID: 10840950 DOI: 10.1002/(sici)1521-3765(20000417)6:8<1294::aid-chem1294>3.0.co;2-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A series of oligomers analogous to poly(p-phenylenevinylene) (PPV), combining naphthalene and benzene as aromatic units, have been synthesized by a Knoevenagel reaction. By measuring UV/Vis spectra, photoluminescence (PL) and electroluminescence (EL), we studied the influence of the position of the naphthalene unit as well as the steric and electronic influences of cyano and alkyloxy substituents on the luminescent properties of these compounds.
Collapse
Affiliation(s)
- P Martinez-Ruiz
- Institut fur Organische Chemie Lehrstuhl II, Universitat Tubingen, Germany
| | | | | | | | | | | |
Collapse
|
34
|
|
35
|
|
36
|
Abstract
A novel Förster donor-acceptor dye pair for an immunoassay based on resonance energy transfer (RET) is characterized with respect to its photophysical properties. As donor and acceptor, we chose the long-wavelength excitable cyanine dyes Cy5 and Cy5.5, respectively. Due to the perfect spectral overlap, an exceptionally high R(0) value of 68.7 A is obtained in solution. For biochemical applications, antibodies (IgG) are labeled with Cy5, while a tracer for competitive binding is synthesized by labeling bovine serum albumin (BSA) with an analyte derivative and Cy5.5. Binding the dyes to proteins at a low dye/protein ratio increases the fluorescence lifetimes and quantum yields, leading to an enhanced R(0) value of 85.2 A. At higher dye/protein ratios, the formation of nonfluorescent dimeric species causes a decrease in the fluorescence lifetime and quantum yield due to RET from monomeric dyes to dimers within one protein molecule. The Förster distances could be calculated using the dimer absorption spectra to 83.9 and 83.6 A for Cy5 and Cy5.5, respectively. Upon binding of the Cy5-labeled IgG to the tracer, efficient quenching of Cy5 fluorescence is observed. Steady-state and time-resolved measurements reveal that approximately 50% of the quenching results in Förster-type RET, while the residual quenching effect is caused by static quenching processes. The applicability of this dye pair is demonstrated in a homogeneous competitive immunoassay for the pesticide simazine.
Collapse
Affiliation(s)
- U Schobel
- Institute of Physical and Theoretical Chemistry, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | | | | | | | | |
Collapse
|
37
|
Kim YC, Quint B, Kessler RW, Oelkrug D. Structural properties of electrochemically designed porous oxide films on AlMg1. J Electroanal Chem (Lausanne) 1999. [DOI: 10.1016/s0022-0728(99)00167-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
38
|
Affiliation(s)
- Matthias Pursch
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Lane C. Sander
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Hans-J. Egelhaaf
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Martin Raitza
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Stephen A. Wise
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Dieter Oelkrug
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| | - Klaus Albert
- Contribution from the Institut für Organische Chemie der Universität Tübingen, Auf der Morgenstelle 18, and Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899
| |
Collapse
|
39
|
Winter G, Heckmann H, Haisch P, Eberhardt W, Hanack M, Lüer L, Egelhaaf HJ, Oelkrug D. Study of Substituent Effects on the Photoconductivity of Soluble 2,(3)- and 1,(4)-Substituted Phthalocyaninato- and Naphthalocyaninatotitanium(IV) Oxides. J Am Chem Soc 1998. [DOI: 10.1021/ja981644y] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Götz Winter
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Heino Heckmann
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Peter Haisch
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Wolfgang Eberhardt
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Michael Hanack
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Larry Lüer
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Hans-Joachim Egelhaaf
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| | - Dieter Oelkrug
- Contribution from the Institut für Organische Chemie, Lehrstuhl für Organische Chemie II, Auf der Morgenstelle 18, and Institut für Physikalische Chemie, Auf der Morgenstelle 8, Universität Tübingen, D-72076 Tübingen, Germany
| |
Collapse
|
40
|
Leipert D, Heiduschka P, Mack J, Egelhaaf HJ, Oelkrug D, Jung G. Spatially Resolved Immobilization of Peptides by Electrochemical Polymerization after Photolytic Cleavage of a Protecting Group. Angew Chem Int Ed Engl 1998; 37:2337-2340. [DOI: 10.1002/(sici)1521-3773(19980918)37:17<2337::aid-anie2337>3.0.co;2-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/1998] [Indexed: 11/08/2022]
|
41
|
Leipert D, Heiduschka P, Mack J, Egelhaaf HJ, Oelkrug D, Jung G. Ortsaufgelöste Immobilisierung von Peptiden durch elektrochemische Polymerisation nach photolytischer Abspaltung einer Schutzgruppe. Angew Chem Int Ed Engl 1998. [DOI: 10.1002/(sici)1521-3757(19980904)110:17<2471::aid-ange2471>3.0.co;2-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
42
|
Abstract
The surface acidities of pharmaceutical excipients are detected by color changes of acid-base indicators on the substrate's surface. To quantify the indicator's transition interval on the surface of hydrophilic excipients, as an organic solvent methanol is introduced for the preparation of indicator-excipient mixtures. The influence of the particle size on the determination of the surface acidity is investigated and particle size did not influence the determination within the particle size range investigated. Surface acidities of common excipients used in preparation of solid dosage forms are presented.
Collapse
Affiliation(s)
- C A Scheef
- Department of Pharmaceutical Technology, Eberhard Karl University, Tübingen, Germany
| | | | | |
Collapse
|
43
|
|
44
|
|
45
|
Oelkrug D, Tompert A, Gierschner J, Egelhaaf HJ, Hanack M, Hohloch M, Steinhuber E. Tuning of Fluorescence in Films and Nanoparticles of Oligophenylenevinylenes. J Phys Chem B 1998. [DOI: 10.1021/jp973225d] [Citation(s) in RCA: 329] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dieter Oelkrug
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Alfred Tompert
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Johannes Gierschner
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Hans-Joachim Egelhaaf
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Michael Hanack
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Michael Hohloch
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| | - Elke Steinhuber
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany
| |
Collapse
|
46
|
Egelhaaf HJ, Oelkrug D, Ellwanger A, Albert K. Investigation of Structure and Mobility of Silica Bonded Stationary Acridine Phases by Means of Fluorescence and NMR Spectroscopy. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1521-4168(19980101)21:1<11::aid-jhrc11>3.0.co;2-a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
47
|
|
48
|
|
49
|
Lehr B, Egelhaaf HJ, Fritz H, Rapp W, Bayer E, Oelkrug D. Molecular Solvation and Mobility in Polymer/Liquid Interphases. A Fluorescence Study on Polystyrene−Poly(ethylene glycol) Microbeads. Macromolecules 1996. [DOI: 10.1021/ma960558k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Lehr
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| | - H. -J. Egelhaaf
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| | - H. Fritz
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| | - W. Rapp
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| | - E. Bayer
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| | - D. Oelkrug
- Institute of Physical Chemistry and Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, and Rapp Polymere GmbH, Ernst-Simon-Strasse 9, D 72072 Tübingen, Germany
| |
Collapse
|
50
|
Oelkrug D, Egelhaaf HJ, Worrall DR, Wilkinson F. Fluorescence yields and molecular orientation of thin organic films: Vapor-Deposited Oligothiophenes ?3T??8T. J Fluoresc 1995; 5:165-70. [DOI: 10.1007/bf00727534] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|