TY - JOUR
A1 - Salffner, Katharina
A1 - Boehm, Michael
A1 - Reich, Oliver
A1 - Löhmannsröben, Hans-Gerd
T1 - A broadband cavity ring-down spectrometer based on an incoherent near infrared light source
JF - Applied physics : B, Lasers and optics
Y1 - 2014
U6 - https://doi.org/10.1007/s00340-014-5762-9
SN - 0946-2171
SN - 1432-0649
VL - 116
IS - 4
SP - 785
EP - 792
PB - Springer
CY - New York
ER -
TY - JOUR
A1 - Bland-Hawthorn, Joss
A1 - Ellis, S. C.
A1 - Leon-Saval, S. G.
A1 - Haynes, R.
A1 - Roth, Martin M.
A1 - Löhmannsröben, Hans-Gerd
A1 - Horton, A. J.
A1 - Cuby, J. -G.
A1 - Birks, T. A.
A1 - Lawrence, J. S.
A1 - Gillingham, P.
A1 - Ryder, S. D.
A1 - Trinh, C.
T1 - A complex multi-notch astronomical filter to suppress the bright infrared sky
JF - Nature Communications
N2 - A long-standing and profound problem in astronomy is the difficulty in obtaining deep near-infrared observations due to the extreme brightness and variability of the night sky at these wavelengths. A solution to this problem is crucial if we are to obtain the deepest possible observations of the early Universe, as redshifted starlight from distant galaxies appears at these wavelengths. The atmospheric emission between 1,000 and 1,800 nm arises almost entirely from a forest of extremely bright, very narrow hydroxyl emission lines that varies on timescales of minutes. The astronomical community has long envisaged the prospect of selectively removing these lines, while retaining high throughput between them. Here we demonstrate such a filter for the first time, presenting results from the first on-sky tests. Its use on current 8 m telescopes and future 30 m telescopes will open up many new research avenues in the years to come.
Y1 - 2011
U6 - https://doi.org/10.1038/ncomms1584
SN - 2041-1723
VL - 2
IS - 50
PB - Nature Publ. Group
CY - London
ER -
TY - JOUR
A1 - Cywinski, Piotr J.
A1 - Olejko, Lydia
A1 - Löhmannsröben, Hans-Gerd
T1 - A time-resolved luminescent competitive assay to detect L-selectin using aptamers as recognition elements
JF - Analytica chimica acta : an international journal devoted to all branches of analytical chemistry
N2 - L-selectin is a protein with potential importance for numerous diseases and clinical disorders. In this paper, we present a new aptamer-based luminescent assay developed to detect L-selectin. The sensing system working principle is based on Forster Resonance Energy Transfer (FRET) from a donor terbium complex (TbC) to an acceptor cyanine dye (Cy5). In the present approach, the biotinylated aptamer is combined with Cy5-labelled streptavidin (Cy5-Strep) to yield an aptamer-based acceptor construct (Apta-Cy5-Strep), while L-selectin is conjugated using luminescent TbC. Upon aptamer binding to the TbC-labelled L-selectin (L-selectin-TbC), permanent donor-acceptor proximity is established which allows for radiationless energy transfer to occur. However, when unlabelled L-selectin is added, it competes with the L-selectin-TbC and the FRET signal decreases as the L-selectin concentration increases. FRET from the TbC to Cy5 was observed with time-gated time-resolved luminescence spectroscopy. A significant change in the corrected luminescence signal was observed in the dynamic range of 10 -500 ng/mL L-selectin, the concentration range relevant for accelerated cognitive decline of Alzheimer's disease, with a limit of detection (LOD) equal to 10 ng/mL. The aptasensor-based assay is homogeneous and can be realized within one hour. Therefore, this method has the potential to become an alternative to tedious heterogeneous analytical methods, e.g. based on enzyme-linked immunosorbent assay (ELISA). (C) 2015 Elsevier B.V. All rights reserved.
KW - Aptamer
KW - FRET
KW - L-selectin
KW - Luminescence spectroscopy
KW - Fluoroassay
KW - Lanthanide
Y1 - 2015
U6 - https://doi.org/10.1016/j.aca.2015.06.045
SN - 0003-2670
SN - 1873-4324
VL - 887
SP - 209
EP - 215
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Zühlke, Martin
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Zenichowski, Karl
A1 - Diener, Marc
A1 - Linscheid, Michael W.
T1 - An electrospray ionization-ion mobility spectrometer as detector for high-performance liquid chromatography
JF - European journal of mass spectrometry
N2 - The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 mu L min(-1) and 1500 mu L min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet-mode. The novel ESI-IM spectrometer tolerates high water contents (<= 90%) and electrolyte concentrations up to 10 mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 mu M for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic IMs.
KW - ESI
KW - IMS
KW - HPLC
KW - spray imaging
KW - neuroleptics
KW - pesticides
KW - surfactants
Y1 - 2015
U6 - https://doi.org/10.1255/ejms.1367
SN - 1469-0667
SN - 1751-6838
VL - 21
IS - 3
SP - 391
EP - 402
PB - WeltTrends
CY - Sussex
ER -
TY - GEN
A1 - Schmälzlin, Elmar
A1 - Dongen, Joost T. van
A1 - Klimant, Ingo
A1 - Marmodée, Bettina
A1 - Steup, Martin
A1 - Fishahn, Joachim
A1 - Geigenberger, Peter
A1 - Löhmannsröben, Hans-Gerd
T1 - An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants
N2 - A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen-sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong autofluorescence of the plant tissue. The method was established using photosynthesis-competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 007
Y1 - 2005
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12232
ER -
TY - JOUR
A1 - Schmalzlin, E.
A1 - van Dongen, J. T.
A1 - Klimant, I.
A1 - Marmodee, Bettina
A1 - Steup, Martin
A1 - Fisahn, Joachim
A1 - Geigenberger, Peter Ludwig
A1 - Löhmannsröben, Hans-Gerd
T1 - An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants
N2 - A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen- sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong auto fluorescence of the plant tissue. The method was established using photosynthesis- competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species
Y1 - 2005
SN - 0006-3495
ER -
TY - JOUR
A1 - Riebe, Daniel
A1 - Eder, Alexander
A1 - Ritschel, Thomas
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Beil, Andreas
A1 - Blaschke, Michael
A1 - Ludwig, Thomas
T1 - Atmospheric pressure chemical ionization of explosives induced by soft X-radiation in ion mobility spectrometry: mass spectrometric investigation of the ionization reactions of drift gasses, dopants and alkyl nitrates
JF - Journal of mass spectrometr
N2 - A promising replacement for the radioactive sources commonly encountered in ion mobility spectrometers is a miniaturized, energy-efficient photoionization source that produce the reactant ions via soft X-radiation (2.8 keV). In order to successfully apply the photoionization source, it is imperative to know the spectrum of reactant ions and the subsequent ionization reactions leading to the detection of analytes. To that end, an ionization chamber based on the photoionization source that reproduces the ionization processes in the ion mobility spectrometer and facilitates efficient transfer of the product ions into a mass spectrometer was developed. Photoionization of pure gasses and gas mixtures containing air, N-2, CO2 and N2O and the dopant CH2Cl2 is discussed. The main product ions of photoionization are identified and compared with the spectrum of reactant ions formed by radioactive and corona discharge sources on the basis of literature data. The results suggest that photoionization by soft X-radiation in the negative mode is more selective than the other sources. In air, adduct ions of O-2 - with H2O and CO2 were exclusively detected. Traces of CO2 impact the formation of adduct ions of O-2 - and Cl -(upon addition of dopant) and are capable of suppressing them almost completely at high CO2 concentrations. Additionally, the ionization products of four alkyl nitrates (ethylene glycol dinitrate, nitroglycerin, erythritol tetranitrate and pentaerythritol tetranitrate) formed by atmospheric pressure chemical ionization induced by X-ray photoionization in different gasses (air, N-2 and N2O) and dopants (CH2Cl2, C2H5Br and CH3I) are investigated. The experimental studies are complemented by density functional theory calculations of the most important adduct ions of the alkyl nitrates (M) used for their spectrometric identification. In addition to the adduct ions [M + NO3](-) and [M + Cl](-), adduct ions such as [M + N2O2](-), [M + Br](-) and [M+ I](-) were detected, and their gas-phase structures and energetics are investigated by density functional theory calculations. Copyright (C) 2016 John Wiley & Sons, Ltd.
KW - ion mobility spectrometry
KW - mass spectrometry
KW - explosives
KW - X-ray
KW - photoionization
KW - alkyl nitrates
Y1 - 2016
U6 - https://doi.org/10.1002/jms.3784
SN - 1076-5174
SN - 1096-9888
VL - 51
SP - 566
EP - 577
PB - Wiley-Blackwell
CY - Hoboken
ER -
TY - JOUR
A1 - Riebe, Daniel
A1 - Zühlke, Martin
A1 - Zenichowski, Karl
A1 - Beitz, Toralf
A1 - Dosche, Carsten
A1 - Löhmannsröben, Hans-Gerd
T1 - Characterization of rhodamine 6G release in electrospray ionization by means of spatially resolved fluorescence spectroscopy
JF - Zeitschrift für physikalische Chemie : international journal of research in physical chemistry and chemical physics
N2 - In the present work, the density distribution of rhodamine 6G ions (R6G) in the gas phase and the droplets of an electrospray plume was studied by spatial and spectral imaging. The intention is to contribute to the fundamental understanding of the release mechanism of gaseous R6G in the electrospray ionization (ESI) process. Furthermore, the influence of ESI-parameters on the release efficiency of R6G, e. g. solvent flow, R6G and salt concentration were examined via direct fluorescence imaging of R6G. A solvent-shift of the fluorescence maximum,lambda(max) = 555 nm in methanolic solution and lambda(max) = 505 nm in gas phase, allows the discrimination between solvated and gaseous R6G. Two experimental setups were used for our measurements. In the first experiment, the R6G fluorescence and the light scattered from the spray plume were imaged in two spatial dimensions using a tunable wavelength filter. The second experiment was designed for obtaining 1-dimensional spatially resolved emission spectra of the spray. Here, the intensity distribution of solvated and gaseous R6G as well as scattered light (lambda = 355 nm) were measured simultaneously.
The results show the distribution of gaseous R6G in the plane, orthogonal to the ESI capillary, decreasing slightly towards the spray center and showing maxima at the cone margins. The distribution of gaseous R6G confirms the preferred release of gaseous ions from nano-droplets, indicating the ion evaporation model (IEM) to be the dominating release mechanism. Up to now, only a few fluorescence spectra of ionic compounds in the gas phase were published because the measurement of emission spectra of mass-selected ions in an ion trap is experimentally challenging. The fluorescence spectrum of gaseous lucigenin at atmospheric pressure is reported for the first time. This spectrum of lucigenin in the gas phase exhibits a blue shift of about Delta lambda = 10 nm in comparison to the corresponding spectrum in methanol.
KW - Fluorescence
KW - Electrospray Ionization
KW - Rhodamine 6G
KW - Gaseous Ions
KW - Lucigenin
Y1 - 2011
U6 - https://doi.org/10.1524/zpch.2011.0149
SN - 0942-9352
VL - 225
IS - 9-10
SP - 1055
EP - 1072
PB - De Gruyter Oldenbourg
CY - München
ER -
TY - JOUR
A1 - Erler, Alexander
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Grothusheitkamp, Daniela
A1 - Kunz, Thomas
A1 - Methner, Frank-Jürgen
T1 - Characterization of volatile metabolites formed by molds on barley by mass and ion mobility spectrometry
JF - Journal of mass spectrometr
N2 - The contamination of barley by molds on the field or in storage leads to the spoilage of grain and the production of mycotoxins, which causes major economic losses in malting facilities and breweries. Therefore, on-site detection of hidden fungus contaminations in grain storages based on the detection of volatile marker compounds is of high interest. In this work, the volatile metabolites of 10 different fungus species are identified by gas chromatography (GC) combined with two complementary mass spectrometric methods, namely, electron impact (EI) and chemical ionization at atmospheric pressure (APCI)-mass spectrometry (MS). The APCI source utilizes soft X-radiation, which enables the selective protonation of the volatile metabolites largely without side reactions. Nearly 80 volatile or semivolatile compounds from different substance classes, namely, alcohols, aldehydes, ketones, carboxylic acids, esters, substituted aromatic compounds, alkenes, terpenes, oxidized terpenes, sesquiterpenes, and oxidized sesquiterpenes, could be identified. The profiles of volatile and semivolatile metabolites of the different fungus species are characteristic of them and allow their safe differentiation. The application of the same GC parameters and APCI source allows a simple method transfer from MS to ion mobility spectrometry (IMS), which permits on-site analyses of grain stores. Characterization of IMS yields limits of detection very similar to those of APCI-MS. Accordingly, more than 90% of the volatile metabolites found by APCI-MS were also detected in IMS. In addition to different fungus genera, different species of one fungus genus could also be differentiated by GC-IMS.
KW - APCI
KW - fungus
KW - gas chromatography
KW - ion mobility spectrometry
KW - mass
KW - spectrometry
KW - mold
KW - soft X-ray
Y1 - 2020
U6 - https://doi.org/10.1002/jms.4501
SN - 1076-5174
SN - 1096-9888
VL - 55
IS - 5
SP - 1
EP - 10
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Schwarze, Thomas
A1 - Dosche, Carsten
A1 - Flehr, Roman
A1 - Klamroth, Tillmann
A1 - Löhmannsröben, Hans-Gerd
A1 - Saalfrank, Peter
A1 - Cleve, Ernst
A1 - Buschmann, Hans-Jürgen
A1 - Holdt, Hans-Jürgen
T1 - Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement
N2 - The [6.6](9,10)anthracenophane 1 (Scheme 1) is a selective fluoroionophore for the detection of PdCl2 with a large fluorescence enhancement factor (I/I-0 > 250).
Y1 - 2010
UR - http://pubs.rsc.org/en/content/articlehtml/2010/cc/b919973j
U6 - https://doi.org/10.1039/B919973j
SN - 1359-7345
ER -
TY - JOUR
A1 - Schwarze, Thomas
A1 - Dosche, Carsten
A1 - Flehr, Roman
A1 - Klamroth, Tillmann
A1 - Löhmannsröben, Hans-Gerd
A1 - Saalfrank, Peter
A1 - Cleve, Ernst
A1 - Buschmann, Hans-Jürgen
A1 - Holdt, Hans-Jürgen
T1 - Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement
Y1 - 2010
UR - http://www.rsc.org/ej/CC/2010/b919973j.pdf
SN - 1359-7345
ER -
TY - GEN
A1 - Riebe, Daniel
A1 - Erler, Alexander
A1 - Brinkmann, Pia
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Gebbers, Robin
T1 - Comparison of Calibration Approaches in Laser-Induced Breakdown Spectroscopy for Proximal Soil Sensing in Precision Agriculture
T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2 - The lack of soil data, which are relevant, reliable, affordable, immediately available, and sufficiently detailed, is still a significant challenge in precision agriculture. A promising technology for the spatial assessment of the distribution of chemical elements within fields, without sample preparation is laser-induced breakdown spectroscopy (LIBS). Its advantages are contrasted by a strong matrix dependence of the LIBS signal which necessitates careful data evaluation. In this work, different calibration approaches for soil LIBS data are presented. The data were obtained from 139 soil samples collected on two neighboring agricultural fields in a quaternary landscape of northeast Germany with very variable soils. Reference analysis was carried out by inductively coupled plasma optical emission spectroscopy after wet digestion. The major nutrients Ca and Mg and the minor nutrient Fe were investigated. Three calibration strategies were compared. The first method was based on univariate calibration by standard addition using just one soil sample and applying the derived calibration model to the LIBS data of both fields. The second univariate model derived the calibration from the reference analytics of all samples from one field. The prediction is validated by LIBS data of the second field. The third method is a multivariate calibration approach based on partial least squares regression (PLSR). The LIBS spectra of the first field are used for training. Validation was carried out by 20-fold cross-validation using the LIBS data of the first field and independently on the second field data. The second univariate method yielded better calibration and prediction results compared to the first method, since matrix effects were better accounted for. PLSR did not strongly improve the prediction in comparison to the second univariate method.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 786
KW - laser-induced breakdown spectroscopy
KW - LIBS
KW - proximal soil sensing
KW - soil nutrients
KW - elemental composition
Y1 - 2019
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-440079
SN - 1866-8372
IS - 786
ER -
TY - JOUR
A1 - Riebe, Daniel
A1 - Erler, Alexander
A1 - Brinkmann, Pia
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Gebbers, Robin
T1 - Comparison of Calibration Approaches in Laser-Induced Breakdown Spectroscopy for Proximal Soil Sensing in Precision Agriculture
JF - Sensors
N2 - The lack of soil data, which are relevant, reliable, affordable, immediately available, and sufficiently detailed, is still a significant challenge in precision agriculture. A promising technology for the spatial assessment of the distribution of chemical elements within fields, without sample preparation is laser-induced breakdown spectroscopy (LIBS). Its advantages are contrasted by a strong matrix dependence of the LIBS signal which necessitates careful data evaluation. In this work, different calibration approaches for soil LIBS data are presented. The data were obtained from 139 soil samples collected on two neighboring agricultural fields in a quaternary landscape of northeast Germany with very variable soils. Reference analysis was carried out by inductively coupled plasma optical emission spectroscopy after wet digestion. The major nutrients Ca and Mg and the minor nutrient Fe were investigated. Three calibration strategies were compared. The first method was based on univariate calibration by standard addition using just one soil sample and applying the derived calibration model to the LIBS data of both fields. The second univariate model derived the calibration from the reference analytics of all samples from one field. The prediction is validated by LIBS data of the second field. The third method is a multivariate calibration approach based on partial least squares regression (PLSR). The LIBS spectra of the first field are used for training. Validation was carried out by 20-fold cross-validation using the LIBS data of the first field and independently on the second field data. The second univariate method yielded better calibration and prediction results compared to the first method, since matrix effects were better accounted for. PLSR did not strongly improve the prediction in comparison to the second univariate method.
KW - laser-induced breakdown spectroscopy
KW - LIBS
KW - proximal soil sensing
KW - soil nutrients
KW - elemental composition
Y1 - 2019
U6 - https://doi.org/10.3390/s19235244
SN - 1424-8220
VL - 19
IS - 23
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Brinkmann, Pia
A1 - Köllner, Nicole
A1 - Merk, Sven
A1 - Beitz, Toralf
A1 - Altenberger, Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Comparison of handheld and echelle spectrometer to assess copper in ores by means of laser-induced breakdown spectroscopy (LIBS)
JF - Minerals
N2 - Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples.
KW - LIBS
KW - copper-bearing minerals
KW - UVR
KW - PCA
KW - PLSR
Y1 - 2023
U6 - https://doi.org/10.3390/min13010113
SN - 2075-163X
VL - 13
IS - 1
PB - MDPI
CY - Basel
ER -
TY - GEN
A1 - Brinkmann, Pia
A1 - Köllner, Nicole
A1 - Merk, Sven
A1 - Beitz, Toralf
A1 - Altenberger, Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Comparison of handheld and echelle spectrometer to assess copper in ores by means of laser-induced breakdown spectroscopy (LIBS)
T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1311
KW - LIBS
KW - copper-bearing minerals
KW - UVR
KW - PCA
KW - PLSR
Y1 - 2023
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-584742
SN - 1866-8372
IS - 1311
ER -
TY - GEN
A1 - McQuade, D. Tyler
A1 - O'Brien, Alexander G.
A1 - Dörr, Markus
A1 - Rajaratnam, Rajathees
A1 - Eisold, Ursula
A1 - Monnanda, Bopanna
A1 - Nobuta, Tomoya
A1 - Löhmannsröben, Hans-Gerd
A1 - Meggers, Eric
A1 - Seeberger, Peter H.
T1 - Continuous synthesis of pyridocarbazoles and initial photophysical and bioprobe characterization
N2 - Pyridocarbazoles when ligated to transition metals yield high affinity kinase inhibitors. While batch photocyclizations enable the synthesis of these heterocycles, the non-oxidative Mallory reaction only provides modest yields and difficult to purify mixtures. We demonstrate here that a flow-based Mallory cyclization provides superior results and enables observation of a clear isobestic point. The flow method allowed us to rapidly synthesize ten pyridocarbazoles and for the first time to document their interesting photophysical attributes. Preliminary characterization reveals that these molecules might be a new class of fluorescent bioprobe.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 246
KW - protein-kinase inhibitors
KW - continuous-flow
KW - photochemical synthesis
KW - light
KW - efficient
KW - phenanthrenes
KW - complexes
Y1 - 2013
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-95214
SP - 4067
EP - 4070
ER -
TY - JOUR
A1 - Cywinski, Piotr J.
A1 - Moro, Artur J.
A1 - Löhmannsröben, Hans-Gerd
T1 - Cyclic GMP recognition using ratiometric QD-fluorophore conjugate nanosensors
JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics
KW - Quantum dots
KW - Naphthyridines
KW - Cyclic GMP
KW - Base pairing
KW - Fluorescent nanoconjugate
KW - Nanosensor
Y1 - 2014
U6 - https://doi.org/10.1016/j.bios.2013.09.002
SN - 0956-5663
SN - 1873-4235
VL - 52
SP - 288
EP - 292
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Morgner, Frank
A1 - Lecointre, Alexandre
A1 - Charbonniere, Loic J.
A1 - Löhmannsröben, Hans-Gerd
T1 - Detecting free hemoglobin in blood plasma and serum with luminescent terbium complexes
JF - Physical chemistry, chemical physics : a journal of European Chemical Societies
N2 - Hemolysis, the rupturing of red blood cells, can result from numerous medical conditions (in vivo) or occur after collecting blood specimen or extracting plasma and serum out of whole blood (in vitro). In clinical laboratory practice, hemolysis can be a serious problem due to its potential to bias detection of various analytes or biomarkers. Here we present the first "mix-and-measure' method to assess the degree of hemolysis in biosamples using luminescence spectroscopy. Luminescent terbium complexes (LTC) were studied in the presence of free hemoglobin (Hb) as indicators for hemolysis in TRIS-buffer, and in fresh human plasma with absorption, excitation and emission measurements. Our findings indicate dynamic as well as resonance energy transfer (FRET) between the LTC and the porphyrin ligand of hemoglobin. This transfer leads to a decrease in luminescence intensity and decay time even at nanomolar hemoglobin concentrations either in buffer or plasma. Luminescent terbium complexes are very sensitive to free hemoglobin in buffer and blood plasma. Due to the instant change in luminescence properties of the LTC in presence of Hb it is possible to access the concentration of hemoglobin via spectroscopic methods without incubation time or further treatment of the sample thus enabling a rapid and sensitive detection of hemolysis in clinical diagnostics.
Y1 - 2015
U6 - https://doi.org/10.1039/c4cp04206a
SN - 1463-9076
SN - 1463-9084
VL - 17
IS - 3
SP - 1740
EP - 1745
PB - Royal Society of Chemistry
CY - Cambridge
ER -
TY - GEN
A1 - Morgner, Frank
A1 - Lecointre, Alexandre
A1 - Charbonnière, Loic J.
A1 - Löhmannsröben, Hans-Gerd
T1 - Detecting free hemoglobin in blood plasma and serum with luminescent terbium complexes
N2 - Hemolysis, the rupturing of red blood cells, can result from numerous medical conditions (in vivo) or occur after collecting blood specimen or extracting plasma and serum out of whole blood (in vitro). In clinical laboratory practice, hemolysis can be a serious problem due to its potential to bias detection of various analytes or biomarkers. Here we present the first ‘‘mix-and-measure’’ method to assess the degree of hemolysis in biosamples using luminescence spectroscopy. Luminescent terbium complexes (LTC) were studied in the presence of free hemoglobin (Hb) as indicators for hemolysis in TRIS-buffer, and in fresh human plasma with absorption, excitation and emission measurements. Our findings indicate dynamic as well as resonance energy transfer (FRET) between the LTC and the porphyrin ligand of hemoglobin. This transfer leads to a decrease in luminescence intensity and decay time even at nanomolar hemoglobin concentrations either in buffer or plasma. Luminescent terbium complexes are very sensitive to free hemoglobin in buffer and blood plasma. Due to the instant change in luminescence properties of the LTC in presence of Hb it is possible to access the concentration of hemoglobin via spectroscopic methods without incubation time or further treatment of the sample thus enabling a rapid and sensitive detection of hemolysis in clinical diagnostics.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 288
Y1 - 2014
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-99485
ER -
TY - JOUR
A1 - Laudien, Robert
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
T1 - Detection of explosive related nitroaromatic compounds (ERNC) by laser-based ion mobility spectrometry
Y1 - 2008
SN - 978-0-8194-7348-6
ER -
TY - JOUR
A1 - Rethfeldt, Nina
A1 - Brinkmann, Pia
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Köllner, Nicole
A1 - Altenberger, Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Detection of Rare Earth Elements in Minerals and Soils by Laser-Induced Breakdown Spectroscopy (LIBS) Using Interval PLS
JF - Minerals
N2 - The numerous applications of rare earth elements (REE) has lead to a growing global demand and to the search for new REE deposits. One promising technique for exploration of these deposits is laser-induced breakdown spectroscopy (LIBS). Among a number of advantages of the technique is the possibility to perform on-site measurements without sample preparation. Since the exploration of a deposit is based on the analysis of various geological compartments of the surrounding area, REE-bearing rock and soil samples were analyzed in this work. The field samples are from three European REE deposits in Sweden and Norway. The focus is on the REE cerium, lanthanum, neodymium and yttrium. Two different approaches of data analysis were used for the evaluation. The first approach is univariate regression (UVR). While this approach was successful for the analysis of synthetic REE samples, the quantitative analysis of field samples from different sites was influenced by matrix effects. Principal component analysis (PCA) can be used to determine the origin of the samples from the three deposits. The second approach is based on multivariate regression methods, in particular interval PLS (iPLS) regression. In comparison to UVR, this method is better suited for the determination of REE contents in heterogeneous field samples. View Full-Text
KW - LIBS
KW - rare earth elements
KW - minerals
KW - PCA
KW - iPLS regression
Y1 - 2021
U6 - https://doi.org/10.3390/min11121379
SN - 2075-163X
VL - 11
SP - 1
EP - 17
PB - MDPI
CY - Basel, Schweiz
ER -
TY - GEN
A1 - Rethfeldt, Nina
A1 - Brinkmann, Pia
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Köllner, Nicole
A1 - Altenberger, Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Detection of Rare Earth Elements in Minerals and Soils by Laser-Induced Breakdown Spectroscopy (LIBS) Using Interval PLS
T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - The numerous applications of rare earth elements (REE) has lead to a growing global demand and to the search for new REE deposits. One promising technique for exploration of these deposits is laser-induced breakdown spectroscopy (LIBS). Among a number of advantages of the technique is the possibility to perform on-site measurements without sample preparation. Since the exploration of a deposit is based on the analysis of various geological compartments of the surrounding area, REE-bearing rock and soil samples were analyzed in this work. The field samples are from three European REE deposits in Sweden and Norway. The focus is on the REE cerium, lanthanum, neodymium and yttrium. Two different approaches of data analysis were used for the evaluation. The first approach is univariate regression (UVR). While this approach was successful for the analysis of synthetic REE samples, the quantitative analysis of field samples from different sites was influenced by matrix effects. Principal component analysis (PCA) can be used to determine the origin of the samples from the three deposits. The second approach is based on multivariate regression methods, in particular interval PLS (iPLS) regression. In comparison to UVR, this method is better suited for the determination of REE contents in heterogeneous field samples. View Full-Text
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1254
KW - LIBS
KW - rare earth elements
KW - minerals
KW - PCA
KW - iPLS regression
Y1 - 2022
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-557469
SN - 1866-8372
SP - 1
EP - 17
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Erler, Alexander
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Grothusheitkamp, Daniela
A1 - Kunz, T.
A1 - Methner, Frank-Jürgen
T1 - Detection of volatile organic compounds in the headspace above mold fungi by GC-soft X-radiation-based APCI-MS
JF - Journal of mass spectrometr
N2 - Mold fungi on malting barley grains cause major economic loss in malting and brewery facilities. Possible proxies for their detection are volatile and semivolatile metabolites. Among those substances, characteristic marker compounds have to be identified for a confident detection of mold fungi in varying surroundings. The analytical determination is usually performed through passive sampling with solid phase microextraction, gas chromatographic separation, and detection by electron ionization mass spectrometry (EI-MS), which often does not allow a confident determination due to the absence of molecular ions. An alternative is GC-APCI-MS, generally, allowing the determination of protonated molecular ions. Commercial atmospheric pressure chemical ionization (APCI) sources are based on corona discharges, which are often unspecific due to the occurrence of several side reactions and produce complex product ion spectra. To overcome this issue, an APCI source based on soft X-radiation is used here. This source facilitates a more specific ionization by proton transfer reactions only. In the first part, the APCI source is characterized with representative volatile fungus metabolites. Depending on the proton affinity of the metabolites, the limits of detection are up to 2 orders of magnitude below those of EI-MS. In the second part, the volatile metabolites of the mold fungus species Aspergillus, Alternaria, Fusarium, and Penicillium are investigated. In total, 86 compounds were found with GC-EI/APCI-MS. The metabolites identified belong to the substance classes of alcohols, aldehydes, ketones, carboxylic acids, esters, substituted aromatic compounds, terpenes, and sesquiterpenes. In addition to substances unspecific for the individual fungus species, characteristic patterns of metabolites, allowing their confident discrimination, were found for each of the 4 fungus species. Sixty-seven of the 86 metabolites are detected by X-ray-based APCI-MS alone. The discrimination of the fungus species based on these metabolites alone was possible. Therefore, APCI-MS in combination with collision induced dissociation alone could be used as a supervision method for the detection of mold fungi.
KW - APCI
KW - gas chromatography
KW - mass spectrometry
KW - mold fungi
KW - soft X-radiation
KW - volatile organic compounds
Y1 - 2018
U6 - https://doi.org/10.1002/jms.4210
SN - 1076-5174
SN - 1096-9888
VL - 53
IS - 10
SP - 911
EP - 920
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Schober, Lars
A1 - Löhmannsröben, Hans-Gerd
T1 - Determination of optical parameters for light penetration in particulate materials and soils with diffuse reflectance (DR) spectroscopy
Y1 - 2000
ER -
TY - JOUR
A1 - Dosche, Carsten
A1 - Kumke, Michael Uwe
A1 - Löhmannsröben, Hans-Gerd
A1 - Ariese, Freek
A1 - Bader, Arjen N.
A1 - Gooijer, Cees
A1 - Miljanic, Ognjen S.
A1 - Iwamoto, M.
A1 - Vollhardt, K. Peter C.
A1 - Puchta, Ralph
A1 - Hommes, N. J. R. V.
T1 - Deuteration effects on the vibronic structure of the fluorescence spectra and the internal conversion rates of triangular [4]phenylene
N2 - Deuteration effects on the vibronic structure of the emission and excitation spectra of triangular [ 4] phenylene (D-3h [4]phenylene) were studied using laser-excited Shpol'skii spectroscopy (LESS) in an octane matrix at 4.2 K. For correct assignment of the vibrational modes, the experimental results were compared with calculated frequencies (B3LYP/6-31G*). CH vibrations were identified by their characteristic isotopic shifts in the spectra of deuterated triangular [4]phenylenes. Two CC stretching modes, at 100 cm(-1) and 1176 cm(-1), suitable as probes for bond strength changes in the excited state, were identified. The isotope effect on the internal conversion rates of triangular [4] phenylene was evaluated from measurements of temperature dependent lifetime. Isotope dependency and the magnitude of the internal conversion rates indicate that internal conversion in triangular [4] phenylene is most likely induced by CH vibrations. The results obtained by LESS and lifetime measurements were compared with PM3 PECI calculations of the excited state structure. The theoretical results and the relation between ground and excited state vibration energies of the 1176 cm(-1) probe vibration indicate a reduction of bond alternation of the central cyclohexatriene ring in the excited state
Y1 - 2004
SN - 1463-9076
ER -
TY - GEN
A1 - Eich, Susanne
A1 - Schmälzlin, Elmar
A1 - Löhmannsröben, Hans-Gerd
T1 - Distributed fiber optical sensing of oxygen with optical time domain reflectometry
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1085
KW - OTDR
KW - optical sensing
KW - molecular oxygen
KW - triangular-[4] phenylene
Y1 - 2021
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-476659
SN - 1866-8372
IS - 1085
ER -
TY - JOUR
A1 - Eich, Susanne
A1 - Schmälzlin, Elmar
A1 - Löhmannsröben, Hans-Gerd
T1 - Distributed fiber optical sensing of Oxygen with optical time domain reflectometry
JF - Sensors
N2 - In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements.
KW - OTDR
KW - optical sensing
KW - molecular oxygen
KW - triangular-[4] phenylene
Y1 - 2013
U6 - https://doi.org/10.3390/s130607170
SN - 1424-8220
VL - 13
IS - 6
SP - 7170
EP - 7183
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Morgner, Frank
A1 - Bennemann, Mark
A1 - Cywiński, Piotr J.
A1 - Kollosche, Matthias
A1 - Górski, Krzysztof
A1 - Pietraszkiewicz, Marek
A1 - Geßner, André
A1 - Löhmannsröben, Hans-Gerd
T1 - Elastic FRET sensors for contactless pressure measurement
JF - RSC Advances : an international journal to further the chemical sciences
N2 - Contactless pressure monitoring based on Forster resonance energy transfer between donor/acceptor pairs immobilized within elastomers is demonstrated. The donor/acceptor energy transfer is employed by dispersing terbium(III) tris[(2-hydroxybenzoyl)-2-aminoethyl] amine complex (LLC, donor) and CdSe/ZnS quantum dots (QD655, acceptor) in styrene-ethylene/buthylene-styrene (SEBS) and poly(dimethylsiloxane) (PDMS). The continuous monitoring of QD luminescence showed a reversible intensity change as the pressure signal is alternated between two stable states indicating a pressure sensitivity of 6350 cps kPa(-1). Time-resolved measurements show the pressure impact on the FRET signal due to an increase of decay time (270 ms up to 420 ms) for the donor signal and parallel drop of decay time (170 mu s to 155 mu s) for the acceptor signal as the net pressure applied. The LLC/QD655 sensors enable a contactless readout as well as space resolved monitoring to enable miniaturization towards smaller integrated stretchable opto-electronics. Elastic FRET sensors can potentially lead to developing profitable analysis systems capable to outdo conventional wired electronic systems (inductive, capacitive, ultrasonic and photoelectric sensors) especially for point-of-care diagnostics, biological monitoring required for wearable electronics.
Y1 - 2017
U6 - https://doi.org/10.1039/c7ra06379b
SN - 2046-2069
VL - 7
SP - 50578
EP - 50583
PB - RSC Publishing
CY - Cambridge
ER -
TY - JOUR
A1 - Cywinski, Piotr J.
A1 - Hammann, Tommy
A1 - Huehn, Dominik
A1 - Parak, Wolfgang J.
A1 - Hildebrandt, Niko
A1 - Löhmannsröben, Hans-Gerd
T1 - Europium-quantum dot nanobioconjugates as luminescent probes for time-gated biosensing
JF - Journal of biomedical optics
N2 - Nanobioconjugates have been synthesized using cadmium selenide quantum dots (QDs), europium complexes (EuCs), and biotin. In those conjugates, long-lived photoluminescence (PL) is provided by the europium complexes, which efficiently transfer energy via Forster resonance energy transfer (FRET) to the QDs in close spatial proximity. As a result, the conjugates have a PL emission spectrum characteristic for QDs combined with the long PL decay time characteristic for EuCs. The nanobioconjugates synthesis strategy and photo-physical properties are described as well as their performance in a time-resolved streptavidin-biotin PL assay. In order to prepare the QD-EuC-biotin conjugates, first an amphiphilic polymer has been functionalized with the EuC and biotin. Then, the polymer has been brought onto the surface of the QDs (either QD655 or QD705) to provide functionality and to make the QDs water dispersible. Due to a short distance between EuC and QD, an efficient FRET can be observed. Additionally, the QD-EuC-biotin conjugates' functionality has been demonstrated in a PL assay yielding good signal discrimination, both from autofluorescence and directly excited QDs. These newly designed QD-EuC-biotin conjugates expand the class of highly sensitive tools for bioanalytical optical detection methods for diagnostic and imaging applications. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
KW - quantum dots
KW - europium complex
KW - amphiphilic polymer assembly
KW - nanobioconjugate
KW - biosensor
KW - time-resolved fluorescence
Y1 - 2014
U6 - https://doi.org/10.1117/1.JBO.19.10.101506
SN - 1083-3668
SN - 1560-2281
VL - 19
IS - 10
PB - SPIE
CY - Bellingham
ER -
TY - JOUR
A1 - Engelhard, Sonja
A1 - Kumke, Michael Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Examples of the application of optical process and quality sensing (OPQS) to beer brewing and polyurethane foaming processes
N2 - Optical methods play an important role in process analytical technologies (PAT). Four examples of optical process and quality sensing (OPQS) are presented, which are based on three important experimental techniques: near- infrared absorption, luminescence quenching, and a novel method, photon density wave (PDW) spectroscopy. These are used to evaluate four process and quality parameters related to beer brewing and polyurethane (PU) foaming processes: the ethanol content and the oxygen (O-2) content in beer, the biomass in a bioreactor, and the cellular structures of PU foam produced in a pilot production plant
Y1 - 2006
UR - http://www.springerlink.com/content/100417
U6 - https://doi.org/10.1007/s00216-005-3364-4
SN - 1618-2642
ER -
TY - JOUR
A1 - Trinh, Christopher Q.
A1 - Ellis, Simon C.
A1 - Bland-Hawthorn, Joss
A1 - Lawrence, Jon S.
A1 - Horton, Anthony J.
A1 - Leon-Saval, Sergio G.
A1 - Shortridge, Keith
A1 - Bryant, Julia
A1 - Case, Scott
A1 - Colless, Matthew
A1 - Couch, Warrick
A1 - Freeman, Kenneth
A1 - Löhmannsröben, Hans-Gerd
A1 - Gers, Luke
A1 - Glazebrook, Karl
A1 - Haynes, Roger
A1 - Lee, Steve
A1 - O'Byrne, John
A1 - Miziarski, Stan
A1 - Roth, Martin M.
A1 - Schmidt, Brian
A1 - Tinney, Christopher G.
A1 - Zheng, Jessica
T1 - Gnosis - the first instrument to use fiber bragg gratings for OH suppression
JF - The astronomical journal
N2 - The near-infrared is an important part of the spectrum in astronomy, especially in cosmology because the light from objects in the early universe is redshifted to these wavelengths. However, deep near-infrared observations are extremely difficult to make from ground-based telescopes due to the bright background from the atmosphere. Nearly all of this background comes from the bright and narrow emission lines of atmospheric hydroxyl (OH) molecules. The atmospheric background cannot be easily removed from data because the brightness fluctuates unpredictably on short timescales. The sensitivity of ground-based optical astronomy far exceeds that of near-infrared astronomy because of this long-standing problem. GNOSIS is a prototype astrophotonic instrument that utilizes "OH suppression fibers" consisting of fiber Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47 and 1.7 mu m. GNOSIS was commissioned at the 3.9 m Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibers, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput (approximate to 60%) and excellent suppression of the skylines by the OH suppression fibers, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS+IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise dominated. OH suppression fibers could potentially impact ground-based astronomy at the level of adaptive optics or greater. However, until a clear reduction in the interline background and the corresponding increasing in sensitivity is demonstrated optimized OH suppression fibers paired with a fiber-fed spectrograph will at least provide a real benefit at low resolving powers.
KW - atmospheric effects
KW - infrared: diffuse background
KW - instrumentation: miscellaneous
Y1 - 2013
U6 - https://doi.org/10.1088/0004-6256/145/2/51
SN - 0004-6256
VL - 145
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Zühlke, Martin
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
A1 - Andreotti, Sandro
A1 - Reinert, Knut
A1 - Zenichowski, Karl
A1 - Diener, Marc
T1 - High-performance liquid chromatography with electrospray ionization ion mobility spectrometry: Characterization, data management, and applications
JF - Journal of separation science
N2 - The combination of high-performance liquid chromatography and electrospray ionization ion mobility spectrometry facilitates the two-dimensional separation of complex mixtures in the retention and drift time plane. The ion mobility spectrometer presented here was optimized for flow rates customarily used in high-performance liquid chromatography between 100 and 1500 mu L/min. The characterization of the system with respect to such parameters as the peak capacity of each time dimension and of the 2D spectrum was carried out based on a separation of a pesticide mixture containing 24 substances. While the total ion current chromatogram is coarsely resolved, exhibiting coelutions for a number of compounds, all substances can be separately detected in the 2D plane due to the orthogonality of the separations in retention and drift dimensions. Another major advantage of the ion mobility detector is the identification of substances based on their characteristic mobilities. Electrospray ionization allows the detection of substances lacking a chromophore. As an example, the separation of a mixture of 18 amino acids is presented. A software built upon the free mass spectrometry package OpenMS was developed for processing the extensive 2D data. The different processing steps are implemented as separate modules which can be arranged in a graphic workflow facilitating automated processing of data.
KW - Amino acids
KW - Electrospray ionization
KW - Ion mobility spectrometry
KW - Pesticides
KW - Two-dimensional separations
Y1 - 2016
U6 - https://doi.org/10.1002/jssc.201600749
SN - 1615-9306
SN - 1615-9314
VL - 39
SP - 4756
EP - 4764
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Dosche, Carsten
A1 - Löhmannsröben, Hans-Gerd
A1 - Raab, Volker
A1 - Raab, Corinna
A1 - Unverzagt, Matthias
T1 - High-resolution spectrometer using combined dispersive and interferometric wavelength separation for raman and laser-induced Breakdown Spectroscopy (LIBS)
JF - Applied spectroscopy : an international journal of spectroscopy ; official publication of the Society for Applied Spectroscopy
N2 - In this paper the concept of a compact high-resolution spectrometer based on the combination of dispersive and interferometric elements is presented. Dispersive elements are used to spectrally resolve the light in one direction with coarse resolution (Delta lambda < 0.5 nm), while perpendicular to that direction an etalon provides high spectral resolution (Delta lambda < 50 pm). This concept for two-dimensional spectroscopy has been implemented for the wavelength range lambda = 350-650 nm. Appropriate algorithms for reconstructing spectra from the two-dimensional raw data and for wavelength calibration were established in an analysis software. Potential applications for this new spectrometer are Raman and laser-induced breakdown spectroscopy (LIBS). Resolutions down to 28 pm (routinely 54 pm) could be realized for these applications.
KW - Raman spectroscopy
KW - Laser-induced breakdown spectroscopy
KW - LIBS
KW - Fabry-Perot etalon
KW - High-resolution spectrometer
Y1 - 2014
U6 - https://doi.org/10.1366/13-07426
SN - 0003-7028
SN - 1943-3530
VL - 68
IS - 9
SP - 1030
EP - 1038
PB - Society for Applied Spectroscopy
CY - Frederick
ER -
TY - GEN
A1 - Niederkrüger, Matthias
A1 - Salb, Christian
A1 - Beck, Michael
A1 - Hildebrandt, Niko
A1 - Löhmannsröben, Hans-Gerd
A1 - Marowsky, Gerd
T1 - Improvement of a fluorescence immunoassay with a compact diode-pumped solid state laser at 315 nm
N2 - We demonstrate the improvement of fluorescence immunoassay (FIA) diagnostics in deploying a newly developed compact diode-pumped solid state (DPSS) laser with emission at 315 nm. The laser is based on the quasi-three-level transition in Nd:YAG at 946 nm. The pulsed operation is either realized by an active Q-switch using an electro-optical device or by introduction of a Cr4+:YAG saturable absorber as passive Q-switch element. By extra-cavity second harmonic generation in different nonlinear crystal media we obtained blue light at 473 nm. Subsequent mixing of the fundamental and the second harmonic in a β-barium-borate crystal provided pulsed emission at 315 nm with up to 20 μJ maximum pulse energy and 17 ns pulse duration. Substitution of a nitrogen laser in a FIA diagnostics system by the DPSS laser succeeded in considerable improvement of the detection limit. Despite significantly lower pulse energies (7 μJ DPSS laser versus 150 μJ nitrogen laser), in preliminary investigations the limit of detection was reduced by a factor of three for a typical FIA.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 016
KW - Immunoassay
KW - Fluoreszenz-Resonanz-Energie-Transfer
KW - Neodym-YAG-Laser
KW - 946 nm
KW - 473 nm
KW - 315 nm
KW - gepulster DPSS Laser
KW - sättigbarer Absorber
KW - fluorescence immunoassay
KW - 946 nm
KW - 473 nm
KW - 315 nm
KW - pulsed DPSS laser
Y1 - 2006
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10150
ER -
TY - JOUR
A1 - Löhmannsröben, Hans-Gerd
T1 - In situ Laser-induced fluorescence (LIF) analysis pf petroleum product-contaminared soil samples
Y1 - 2000
ER -
TY - JOUR
A1 - Prüfert, Chris
A1 - Urban, Raphael David
A1 - Fischer, Tillmann Georg
A1 - Villatoro, José Andrés
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Belder, Detlev
A1 - Zeitler, Kirsten
A1 - Löhmannsröben, Hans-Gerd
T1 - In situ monitoring of photocatalyzed isomerization reactions on a microchip flow reactor by IR-MALDI ion mobility spectrometry
JF - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica
N2 - The visible-light photocatalyticE/Zisomerization of olefins can be mediated by a wide spectrum of triplet sensitizers (photocatalysts). However, the search for the most efficient photocatalysts through screenings in photo batch reactors is material and time consuming. Capillary and microchip flow reactors can accelerate this screening process. Combined with a fast analytical technique for isomer differentiation, these reactors can enable high-throughput analyses. Ion mobility (IM) spectrometry is a cost-effective technique that allows simple isomer separation and detection on the millisecond timescale. This work introduces a hyphenation method consisting of a microchip reactor and an infrared matrix-assisted laser desorption ionization (IR-MALDI) ion mobility spectrometer that has the potential for high-throughput analysis. The photocatalyzedE/Zisomerization of ethyl-3-(pyridine-3-yl)but-2-enoate (E-1) as a model substrate was chosen to demonstrate the capability of this device. Classic organic triplet sensitizers as well as Ru-, Ir-, and Cu-based complexes were tested as catalysts. The ionization efficiency of theZ-isomer is much higher at atmospheric pressure which is due to a higher proton affinity. In order to suppress proton transfer reactions by limiting the number of collisions, an IM spectrometer working at reduced pressure (max. 100 mbar) was employed. This design reduced charge transfer reactions and allowed the quantitative determination of the reaction yield in real time. Among 14 catalysts tested, four catalysts could be determined as efficient sensitizers for theE/Zisomerization of ethyl cinnamate derivativeE-1. Conversion rates of up to 80% were achieved in irradiation time sequences of 10 up to 180 s. With respect to current studies found in the literature, this reduces the acquisition times from several hours to only a few minutes per scan.
KW - microchip
KW - reaction monitoring
KW - IR-MALDI
KW - ion mobility spectrometry
KW - photochemistry
KW - photocatalysis
KW - Olefin isomerization
Y1 - 2020
U6 - https://doi.org/10.1007/s00216-020-02923-y
SN - 1618-2642
SN - 1618-2650
VL - 412
IS - 28
SP - 7899
EP - 7911
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Haitzer, Markus
A1 - Löhmannsröben, Hans-Gerd
A1 - Steinberg, Christian E. W.
A1 - Zimmermann, Ute
T1 - In vivo laser-induced fluorescence detection of pyrene in nematodes and determination of pyrene binding constants for humic substances by fluorescences quenching and bioaccumulation experiments
Y1 - 2000
ER -
TY - JOUR
A1 - Lemke, Matthias
A1 - Fernandez-Trujillo, R.
A1 - Löhmannsröben, Hans-Gerd
T1 - In-situ LIF analysis of biological and petroleum-based hydraulic oils on soil
N2 - Absorption and fluorescence properties of 4 hydraulic oils ( 3 biological and 1 petroleum-based) were investigated. In-situ LIF (laser-induced fluorescence) analysis of the oils on a brown sandy loam soil was performed. With calibration, quantitative detection was achieved. Estimated limits of detection were below ca. 500 mg/kg for the petroleum-based oil and ca. 2000 mg/kg for one biological oil. A semi-quantitative classification scheme is proposed for monitoring of the biological oils. This approach was applied to investigate the migration of a biological oil in soil- containing compartments, namely a soil column and a soil bed
Y1 - 2005
SN - 1424-8220
ER -
TY - GEN
A1 - Lemke, Matthias
A1 - Fernández-Trujillo, Rebeca
A1 - Löhmannsröben, Hans-Gerd
T1 - In-situ LIF analysis of biological and petroleum-based hydraulic oils on soil
N2 - Absorption and fluorescence properties of 4 hydraulic oils (3 biological and 1 petroleum-based) were investigated. In-situ LIF (laser-induced fluorescence) analysis of the oils on a brown sandy loam soil was performed. With calibration, quantitative detection was achieved. Estimated limits of detection were below ca. 500 mg/kg for the petroleum-based oil and ca. 2000 mg/kg for one biological oil. A semi-quantitative classification scheme is proposed for monitoring of the biological oils. This approach was applied to investigate the migration of a biological oil in soil-containing compartments, namely a soil column and a soil bed.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 011
KW - in-situ
KW - optical oil sensor
KW - lubricants
KW - hydraulic oils
KW - soil
KW - laser induced
Y1 - 2005
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12268
ER -
TY - JOUR
A1 - Roth, Martin M.
A1 - Löhmannsröben, Hans-Gerd
A1 - Kelz, A.
A1 - Kumke, Michael Uwe
T1 - innoFSPEC : fiber optical spectroscopy and sensing
Y1 - 2008
SN - 978-0-819-47228-1
ER -
TY - JOUR
A1 - Zakrevskyy, Yuriy
A1 - Cywinski, Piotr
A1 - Cywinska, Magdalena
A1 - Paasche, Jens
A1 - Lomadze, Nino
A1 - Reich, Oliver
A1 - Löhmannsröben, Hans-Gerd
A1 - Santer, Svetlana
T1 - Interaction of photosensitive surfactant with DNA and poly acrylic acid
JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
Y1 - 2014
U6 - https://doi.org/10.1063/1.4862679
SN - 0021-9606
SN - 1089-7690
VL - 140
IS - 4
PB - American Institute of Physics
CY - Melville
ER -
TY - JOUR
A1 - Kumke, Michael Uwe
A1 - Löhmannsröben, Hans-Gerd
T1 - Introduction to fluorescence spectroscopy
Y1 - 2009
ER -
TY - JOUR
A1 - Brendler, Christian
A1 - Riebe, Daniel
A1 - Ritschel, Thomas
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
T1 - Investigation of neuroleptics and other aromatic compounds by laser-based ion mobility mass spectrometry
JF - Analytical & bioanalytical chemistry
N2 - Laser-based ion mobility (IM) spectrometry was used for the detection of neuroleptics and PAH. A gas chromatograph was connected to the IM spectrometer in order to investigate compounds with low vapour pressure. The substances were ionized by resonant two-photon ionization at the wavelengths lambda = 213 and 266 nm and pulse energies between 50 and 300 mu J. Ion mobilities, linear ranges, limits of detection and response factors are reported. Limits of detection for the substances are in the range of 1-50 fmol. Additionally, the mechanism of laser ionization at atmospheric pressure was investigated. First, the primary product ions were determined by a laser-based time-of-flight mass spectrometer with effusive sample introduction. Then, a combination of a laser-based IM spectrometer and an ion trap mass spectrometer was developed and characterized to elucidate secondary ion-molecule reactions that can occur at atmospheric pressure. Some substances, namely naphthalene, anthracene, promazine and thioridazine, could be detected as primary ions (radical cations), while other substances, in particular acridine, phenothiazine and chlorprothixene, are detected as secondary ions (protonated molecules). The results are interpreted on the basis of quantum chemical calculations, and an ionization mechanism is proposed.
KW - Ion mobility spectrometry
KW - Mass spectrometry
KW - Gas chromatography
KW - Laser ionization
KW - REMPI
KW - Neuroleptics
Y1 - 2013
U6 - https://doi.org/10.1007/s00216-012-6654-7
SN - 1618-2642
VL - 405
IS - 22
SP - 7019
EP - 7029
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Beitz, Toralf
A1 - Laudien, Robert
A1 - Löhmannsröben, Hans-Gerd
A1 - Kallies, Bernd
T1 - Ion mobility spectrometric investigation of aromatic cations in the gas phase
N2 - In this work, ion mobility (IM) spectra of more than 50 aromatic compounds were recorded with a laser-based IM spectrometer at atmospheric pressure. IM spectra of PAH in the laser desorption experiment show a high complexity resulting from the occurrence of monomeric, dimeric, and oligomeric cluster ions. The mobilities of all compounds were determined in helium as drift gas. This allows the calculation of the diffusion cross sections (Omega(calc)) on the basis of the exact hard sphere scattering model and their comparison with the experimentally determined diffusion cross sections (Omega(exp)). Extended Omega(exp)/Omega(calc) and Omega(exp/)mass correlations were performed in order to gain insight into conformational properties of cationic alkyl benzenes and internal rotation of phenyl rings in aromatic ions. This is demonstrated with some examples, such as the evaluation of the dihedral angle of the ions of 9,10- diphenylanthracene, o- and m-terphenyl, and 1,2,3- and 1,3,5-triphenylbenzene. Furthermore, sandwich and T-structures of dimeric PAH cations are discussed. The analysis was extended to oligomeric ions with up to nine monomer units. Experimental evidence is presented suggesting the formation of pi-stacks with a transition toward modified pi-stacks with increasing cluster size. The distance between monomeric units in dimeric and oligomeric ions was obtained
Y1 - 2006
UR - http://pubs.acs.org/journal/jpcafh
U6 - https://doi.org/10.1021/Jp055335n
SN - 1089-5639
ER -
TY - JOUR
A1 - Villatoro, José Andrés
A1 - Zühlke, Martin
A1 - Riebe, Daniel
A1 - Riedel, Jens
A1 - Beitz, Toralf
A1 - Löhmannsröben, Hans-Gerd
T1 - IR-MALDI ion mobility spectrometry
JF - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry and Analusis
N2 - The novel combination of infrared matrix-assisted laser dispersion and ionization (IR-MALDI) with ion mobility (IM) spectrometry makes it possible to investigate biomolecules in their natural environment, liquid water. As an alternative to an ESI source, the IR-MALDI source was implemented in an in-house-developed ion mobility (IM) spectrometer. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse (lambda = 2.94 mu m, 6 ns pulse width), which disperses the liquid as nano- and micro-droplets. The prerequisites for the application of IR-MALDI-IM spectrometry as an analytical method are narrow analyte ion signal peaks for a high spectrometer resolution. This can only be achieved by improving the desolvation of ions. One way to full desolvation is to give the cluster ions sufficient time to desolvate. Two methods for achieving this are studied: the implementation of an additional drift tube, as in ESI-IM-spectrometry, and the delayed extraction of the ions. As a result of this optimization procedure, limits of detection between 5 nM and 2.5 mu M as well as linear dynamic ranges of 2-3 orders of magnitude were obtained for a number of substances. The ability of this method to analyze simple mixtures is illustrated by the separation of two different surfactant mixtures.
KW - Ion mobility spectrometry
KW - IR-MALDI
KW - Laser
Y1 - 2016
U6 - https://doi.org/10.1007/s00216-016-9739-x
SN - 1618-2642
SN - 1618-2650
VL - 408
SP - 6259
EP - 6268
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Villatoro, José Andrés
A1 - Zühlke, Martin
A1 - Riebe, Daniel
A1 - Beitz, Toralf
A1 - Weber, Marcus
A1 - Riedel, Jens
A1 - Löhmannsröben, Hans-Gerd
T1 - IR-MALDI ion mobility spectrometry: physical source characterization and application as HPLC detector
JF - International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry
N2 - Infrared matrix-assisted laser dispersion and ionization (IR-MALDI) in combination with ion mobility (IM) spectrometry enables the direct analysis of biomolecules in aqueous solution. The release of ions directly from an aqueous solution is based on a phase explosion, induced by the absorption of an IR laser pulse, which disperses the liquid as vapor, nano-and micro-droplets. The ionization process is characterized initially by a broad spatial distribution of the ions, which is a result of complex fluid dynamics and desolvation kinetics. These processes have a profound effect on the shape and width of the peaks in the IM spectra. In this work, the transport of ions by the phase explosion-induced shockwave could be studied independently from the transport by the electric field. The shockwave-induced mean velocities of the ions at different time scales were determined through IM spectrometry and shadowgraphy. The results show a deceleration of the ions from 118 m.s(-1) at a distance of 400 mu m from the liquid surface to 7.1 m.s(-1) at a distance of 10 mm, which is caused by a pile-up effect. Furthermore, the desolvation kinetics were investigated and a first-order desolvation constant of 325 +/- 50 s(-1) was obtained. In the second part, the IR-MALDI-IM spectrometer is used as an HPLC detector for the two-dimensional separation of a pesticide mixture.
KW - Ion mobility spectrometry
KW - IR-MALDI
KW - Shadowgraphy
KW - Laser
KW - Imaging
KW - HPLC
Y1 - 2016
U6 - https://doi.org/10.1007/s12127-016-0208-1
SN - 1435-6163
SN - 1865-4584
VL - 19
SP - 197
EP - 207
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Horner, G.
A1 - Lau, Steffen
A1 - Kantor, Z.
A1 - Löhmannsröben, Hans-Gerd
T1 - Isotope selective analysis of CO2 with tunable diode laser (TDL) spectroscopy in the NIR
N2 - The performance of a home-built tunable diode laser (TDL) spectrometer, aimed at multi-line detection of carbon dioxide, has been evaluated and optimized. In the regime of the (3001)(III) <-- (000) band of (CO2)-C-12 around 1.6 mum, the dominating isotope species (CO2)-C-12, (CO2)-C-13, and (COO)-C-12-O-18-O-16 were detected simultaneously without interference by water vapor. Detection limits in the range of few ppmv were obtained for each species utilizing wavelength modulation (WM) spectroscopy with balanced detection in a long-path absorption cell set-up. High sensitivity in conjunction with high precision-typically +/-1% and +/-6% for 3% and 0.7% of CO2, respectively-renders this experimental approach a promising analytical concept for isotope-ratio determination of carbon dioxide in soil and breath gas. For a moderate (CO2)-C-12 line, the pressure dependence of the line profile was characterized in detail, to account for pressure effects on sensitive measurements
Y1 - 2004
SN - 0003-2654
ER -
TY - GEN
A1 - Hörner, Gerald
A1 - Lau, Steffen
A1 - Kantor, Zoltan
A1 - Löhmannsröben, Hans-Gerd
T1 - Isotope selective analysis of CO2 with tunable diode laser (TDL) spectroscopy in the NIR
N2 - The performance of a home-built tunable diode laser (TDL) spectrometer, aimed at multi-line detection of carbon dioxide, has been evaluated and optimized. In the regime of the (3001)III / (000) band of 12CO2 around 1.6 μm, the dominating isotope species 12CO2, 13CO2, and 12C18O16O were detected simultaneously without interference by water vapor. Detection limits in the range of few ppmv were obtained for each species utilizing wavelength modulation (WM) spectroscopy with balanced detection in a long-path absorption cell set-up. High sensitivity in conjunction with high precision —typically ±1‰ and ±6‰ for 3% and 0.7% of CO2, respectively— renders this experimental approach a promising analytical concept for isotope-ratio determination of carbon dioxide in soil and breath gas. For a moderate 12CO2 line, the pressure dependence of the line profile was characterized in detail, to account for pressure effects on sensitive measurements.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 020
KW - Isotopenverhältnis
KW - Kohlendioxid
KW - Diodenlaserspektroskopie
KW - Isotope ratio
KW - carbon monoxide
KW - diode laser spectroscopy
Y1 - 2004
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10167
ER -
TY - JOUR
A1 - Löhmannsröben, Hans-Gerd
A1 - Lau, Steffen
T1 - Isotope selectivity in environmental monitoring : NIR diode laser spectroscopy for isotope-selective sensing of soil-respired carbon dioxide
Y1 - 2005
ER -
TY - GEN
A1 - Lau, Steffen
A1 - Salffner, Katharina
A1 - Löhmannsröben, Hans-Gerd
T1 - Isotopic resolution of carbon monoxide and carbon dioxide by NIR diode laser spectroscopy
N2 - Near-infrared (NIR) absorption spectroscopy with tunable diode lasers allows the simultaneous detection of the three most important isotopologues of carbon dioxide (12CO2, 13CO2, 12C18O16O) and carbon monoxide (12CO, 13CO, 12C18O). The flexible and compact fiber-optic tunable diode laser absorption spectrometer (TDLAS) allows selective measurements of CO2 and CO with high isotopic resolution without sample preparation since there is no interference with water vapour. For each species, linear calibration plots with a dynamic range of four orders of magnitude and detection limits (LOD) in the range of a few ppm were obtained utilizing wavelength modulation spectroscopy (WMS) with balanced detection in a Herriott-type multipass cell. The high performance of the apparatus is illustrated by fill-evacuation-refill cycles.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 017
KW - Isotop
KW - Kohlenmonoxid
KW - Kohlendioxid
KW - Diodenlaserspektroskopie
KW - isotope
KW - carbon monoxide
KW - carbon dioxide
KW - diode laser spectroscopy
Y1 - 2006
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10135
ER -