TY  - JOUR
AB  - RATIONALE: Aromatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) pose significant risks to human health and the environment due to their toxic and carcinogenic properties. These depend strongly on molecular structure, with even isomers exhibiting different characteristics. Consequently, when conducting a risk assessment of a sample, a rapid and reliable detection technique capable of differentiating between isomers is crucial. METHODS: Time-of-flight mass spectrometry (TOFMS) combined with (1 + 1) resonance-enhanced multiphoton ionization ((1 + 1)-REMPI) has proven to be a promising approach due to its wavelength selectivity for different structures. An optical parametric oscillator generated UV radiation from 213 to 300 nm from the third harmonic (355 nm) of a Nd:YAG laser beam. A thermogravimetric system was applied to transfer the substances into the gas phase. RESULTS: We performed REMPI spectroscopy of 48 monocyclic and polycyclic aromatic hydrocarbons, including compounds with various substituents (alkyl groups, -OCH3, -SH, -OH, -Cl) and heteroatoms (N, O, S). The observed spectral shifts correlate with ring number as well as the type, number, and position of substituents and heteroatoms. While these shifts are comparable to trends observed in absorption spectra, variations in intensity arise due to differences in excited-state lifetimes and the cross sections of both absorption steps. It was further demonstrated that the selected wavelength range, extending to a lower limit of 213 nm, is especially beneficial for the naphthalenes. The relative photoionization cross sections of the investigated compounds have been calculated, showing that the aforementioned structural dependencies also influence the ionization efficiency. CONCLUSIONS: In common applications, these results may be used to determine a suitable laser wavelength for the substances of interest in order to achieve a higher level of sensitivity. For tunable laser applications, they serve as a reference for distinguishing and quantifying isomers in complex mixtures based on spectral shifts.
AU  - Schwarz, C.*
AU  - Etscheidt, F.*
AU  - Gehm, C.*
AU  - Passig, J.
AU  - Ehlert, S.*
AU  - Streibel, T.
AU  - Zimmermann, R.
C1  - 74992
C2  - 57780
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
TI  - Resonance-enhanced multiphoton ionization spectroscopy of monocyclic and polycyclic aromatic hydrocarbons in the gas phase.
JO  - Rapid Commun. Mass Spectrom.
VL  - 39
IS  - 19
PB  - Wiley
PY  - 2025
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: Sugars are key molecules of life but challenging to detect via Electrospray ionization mass spectrometry (ESI-MS). Unfortunately, sugars are challenging analytes for mass spectrometric methods due to their high gas-phase deprotonation energies and low gas-phase proton affinities which make them difficult to be ionized in high abundance for MS detection. METHODS: Hydrogen bond interactions in H2 PO4 ̅ - Saccharide anionic systems both experimentally (via Electrospray Fourier transform ion cyclotron resonance mass spectrometry, ESI-FT-ICR-MS) and computationally by several sophisticated density-functional theoretical (DFT and DFT-D3) methods. RESULTS: H2 PO4 ̅ dopant boosts the detection of sugars up to 51-times in case of sucrose and up to 263-times for glucose (at 0.1 ppm concentration level). H2 PO4 ̅ binds toward sugar molecules with noticeably more hydrogen bonds than the established dopant chloride Cl ̅ does, with increasing binding energies in the order: Monosaccharides < Trisaccharides < Disaccharides. Analysis of a complex oak plant sample revealed that NH4 H2 PO4 specifically labeled a diverse set of sugar-type plant metabolites in form of [M+H2 PO4 ] ̅ complexes. CONCLUSIONS: We reveal the mechanism of interaction of H2 PO4 ̅ with different sugars and glycosylated organic compounds, which significantly enhances their ionization in mass spectrometry. A computational and experimental investigation is presented. A strong correlation between MS signal intensities of detected [M+H2 PO4 ] ̅ anions of different saccharides and their calculated dissociation enthalpies was revealed. Thus, the variation of MS signal intensities can be very well described to a large extent by variation of calculated saccharides affinities toward H2 PO4 ̅ dopant anion, showing that DFT-D3 can very well describe experimental FT-ICR-MS observations.
AU  - Ruf, A.
AU  - Kanawati, B.
AU  - Schmitt-Kopplin, P.
C1  - 64533
C2  - 52262
TI  - Dihydrogen Phosphate anion boosts the detection of sugars in ESI-MS: A combined experimental and computational investigation.
JO  - Rapid Commun. Mass Spectrom.
VL  - 36
IS  - 11
PY  - 2022
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Rationale Fast and sensitive detection of aromatic hydrocarbons (AHs) in water is of high importance because of their significant impact on human health and the environment. For this, resonance-enhanced multiphoton ionization (REMPI) coupled to trap-and-release membrane-introduction mass spectrometry (T&R-MIMS) offers the possibility of sensitive on-line water analysis with a time resolution of minutes. Methods REMPI is a versatile tool for sensitive gas-phase analysis, in which AHs are selectively ionized in complex gas mixtures by the subsequent absorption of at least two photons. In T&R-MIMS, selective extraction and enrichment of analytes from water can be achieved using semipermeable membranes. By the subsequent stimulated desorption of enriched compounds, mass spectrometric detection is enabled. Results We present an external T&R inlet for hollow-fiber membranes coupled to REMPI time-of-flight mass spectrometry, which enables direct and sensitive detection of semi-volatile AHs in water. In laboratory experiments, spiked water samples were analyzed. For the investigated compounds, limits of detection (LODs) in the range 1-47 ng/L were determined. The LODs are approximately one order of magnitude lower than in a previously reported continuous membrane-introduction approach using a planar membrane. Further improvement of LOD may be realized by extending the trapping time and by increasing the release temperature. Furthermore, the system was applied to investigate different fuels suspended in water and real water samples. The obtained data are in good agreement with findings of a former study. Conclusions In the framework of the present study, we demonstrate the high potential of the combination of REMPI and T&R-MIMS in the form of a newly developed external hollow-fiber membrane inlet. With the developed system, semi-volatile AHs can be directly detected down to ng/L levels on a minute time scale. The approach thus may pave the way to future ship application in marine sciences, natural resources exploration or pollutant and hazard detection.
AU  - Gehm, C.*
AU  - Streibel, T.
AU  - Ehlert, S.*
AU  - Schulz-Bull, D.*
AU  - Zimmermann, R.
C1  - 59421
C2  - 48808
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
TI  - External trap-and-release membrane inlet for photoionization mass spectrometry: Towards fast direct analysis of aromatic pollutants in aquatic systems.
JO  - Rapid Commun. Mass Spectrom.
VL  - 35
IS  - 2
PB  - Wiley
PY  - 2021
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: Mass spectrometry imaging (MSI) is a powerful tool for mapping the surface of a sample. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization (AP-MALDI) offer complementary capabilities. Here, we present a workflow to apply both techniques to a single tissue section and combine the resulting data on the example of human colon cancer tissue. METHODS: Following cryo-sectioning, images were acquired using the high spatial resolution (1 μm pixel size) provided by TOF-SIMS. The same section was then coated with a para-nitroaniline matrix and images were acquired using AP-MALDI coupled to an Orbitrap mass spectrometer, offering high mass resolution, high mass accuracy and MS/MS capabilities. Datasets provided by both mass spectrometers were converted into the open and vendor-independent imzML file format and processed with the open-source software MSiReader. RESULTS: The TOF-SIMS and AP-MALDI-MS mass spectra show strong signals of fatty acids, cholesterol, phosphatidylcholine and sphingomyelin. We showed a high correlation between the fatty acid ions detected with TOF-SIMS in negative ion mode and the phosphatidylcholine ions detected with AP-MALDI in positive ion mode using a similar setting for visualization. Histological staining on the same section allowed the identification of the anatomical structures and their correlation with the ion images. CONCLUSIONS: This multimodal approach using two MSI platforms shows an excellent complementarity for the localization and identification of lipids. The spatial resolution of both systems is at or close to cellular dimensions and thus spatial correlation can only be obtained if the same tissue section is analyzed sequentitially. imzML-based data processing allows a real correlation of the imaging datasets provided by these two technologies and opens the way for a more complete molecular view of the anatomical structures of biological tissues.
AU  - Desbenoit, N.*
AU  - Walch, A.K.
AU  - Spengler, B.*
AU  - Brunelle, A.*
AU  - Römpp, A.*
C1  - 52278
C2  - 43894
CY  - Hoboken
SP  - 159-166
TI  - Correlative mass spectrometry imaging, applying TOF-SIMS and AP-MALDI to a single tissue section.
JO  - Rapid Commun. Mass Spectrom.
VL  - 32
IS  - 2
PB  - Wiley
PY  - 2017
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: The recent development of compound-specific online chlorine isotope analysis ((37) Cl-CSIA) methods has fostered dual chlorine-carbon isotope studies to gain better insights into sources and environmental transformation reactions of chlorinated ethenes (CEs). 1-point and 2-point calibration schemes are currently used to convert raw data to the international δ(37) ClSMOC scale, but a critical evaluation of best practices to arrive at reliable δ(37) ClSMOC signatures and enrichment factors was missing and is presented here. METHODS: Aqueous solutions of neat PCE and TCE and aqueous samples from a TCE biodegradation experiment with pure cultures of Desulfitobacterium hafniense Y51 were analysed for their chlorine isotope ratios using GC/qMS and GC/IRMS. The δ(37) ClSMOC values were obtained using 1-point and 2-point calibration schemes. Chlorine isotope enrichment factors, ɛCl , were calculated using both approaches and the corresponding bias of δ(37) ClSMOC values introduced by the different types of calibration was determined. RESULTS: Different calibration methods resulted in significant differences (up to 30%) in both δ(37) Cl signatures and ɛCl -values. CONCLUSIONS: Our results demonstrate that a 2-point calibration together with comprehensive information on reference materials is indispensable and should become standard practice for reliable (37) Cl-CSIA of organic compounds.
AU  - Ebert, K.A.*
AU  - Laskov, C.*
AU  - Elsner, M.
AU  - Haderlein, S.B.*
C1  - 49580
C2  - 40836
CY  - Hoboken
SP  - 68-74
TI  - Calibration bias of experimentally determined chlorine isotope enrichment factors: The need for a two-point calibration in compound-specific chlorine isotope analysis.
JO  - Rapid Commun. Mass Spectrom.
VL  - 31
IS  - 1
PB  - Wiley-blackwell
PY  - 2017
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: Peak picking algorithms in mass spectrometry face the challenge of picking the correct signals from a mass spectrum. In some cases signal wiggles (side lobes) are also chosen in the produced mass list as if they were real signals. Constraints which are defined in such algorithms do not always guarantee wiggle free accurate mass list generation out of raw mass spectra. This problem intensifies with acquisitions, which are accompanied with longer transients. Thus, the problem represents a contemporary issue, which propagates with modern high memory digitizers and exists in both MS and MS/MS spectra. METHODS: A solariX FTMS mass spectrometer with an Infinity ICR cell (Bruker Daltonics, Bremen, Germany) coupled to a 12 Tesla magnet (Magnex, UK) was used for the experimental study. Time domain transients of several different data point lengths 512k, 1M, 2M, 4M, 8M were obtained and are Fourier transformed to obtain frequency spectra which show the effect of the transient truncation on sinc wiggle developments in the FT-ICR-MS. MATLAB Simulations were also performed to investigate the origin of the Fourier Transform (FT) artifacts. RESULTS: A new filter is developed to identify and remove FT artifacts (sinc side lobes) from both frequency and mass spectra. The newly developed filter is based on distinguishing between the FWHM of the correct frequency/mass signals and the FWHM of their corresponding wiggles. The filter draws a reliable confidence limit of resolution range, within which a correct frequency/mass signal is identified. The filter is applicable over a wide mass range of metabolic interest (100-1200) amu. CONCLUSIONS: The origin of FT artifacts due to time-domain transient truncations was thoroughly investigated both experimentally and by simulations in this study. A new solution for this problem with automatic recognition and elimination of these FT artifacts (side lobes / wiggles) is provided, which is independent of any intensity thresholds, magnetic field strengths and time-domain transient lengths.
AU  - Kanawati, B.
AU  - Bader, T.M.
AU  - Wanczek, K.P.*
AU  - Li, Y.
AU  - Schmitt-Kopplin, P.
C1  - 51525
C2  - 43284
CY  - Hoboken
SP  - 1607-1615
TI  - FT-artifacts and power-function resolution filter in fourier transform mass spectrometry.
JO  - Rapid Commun. Mass Spectrom.
VL  - 31
IS  - 19
PB  - Wiley
PY  - 2017
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: This study examines the electrospray ionization mass spectrometry (ESI-MS), in-source collision-induced dissociation (CID) fragmentation and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of a synthetic pair of β- and α-anomers of the amphiphilic cholesteryl polyethoxy neoglycolipids containing the 2-azido-2-deoxy-D-galactosyl-D-GalN3 moiety. We describe the novel and unique in situ gas-phase formation of a C-glycoside ion formed during all these gas-phase processes and propose a reasonable mechanism for its formation. METHODS: The synthetic amphiphilic glycolipids were composed of the 2-deoxy-2-azido-D-galactosyl moiety (GalN3 , the hydrophilic part) covalently attached to a polyethoxy spacer which is covalently linked to the cholesteryl moiety (hydrophobic part). The 2-azido-2-deoxy-α- and β-D-galactosyl-containing glycolipids were studied by in-time and in-space ESI-MS and CID-MS/MS in positive ion mode, with quadrupole ion trap (QIT), quadrupole-quadrupole-time-of-flight (QqTOF), and Fourier transform ion cyclotron resonance (FTICR) instruments. RESULTS: Conventional single-stage ESI-MS analysis showed the formation of the protonated molecule. During the single-stage ESI-MS analysis and the CID-MS/MS of the [M+H](+) and [M+NH4 ](+) adducts obtained from both glycolipid anomers, the presence of a series of specific product ions with different intensities was observed, consistent with the [C-glycoside+H-N2 ](+) , [cholestadiene+H](+) , 2-deoxy-2-D-azido-galactosyl [GalN3 ](+) , [GalNH](+) and [sugar-Spacer+H](+) ions. CONCLUSIONS: The gas-phase formation of the [C-glycoside+H-N2 ](+) ion isolated from the glycolipid anomers was observed during both the ESI-MS of the glycolipids and the CID-MS/MS analyses of the [M+H](+) ions and it was found to occur by an intramolecular rearrangement involving an ion-molecule complex. CID-QqTOF-MS/MS and CID-FTICR-MS(2) analysis allowed the differentiation of the two glycolipid anomers and showed noticeable variation in the intensities of the product ions.
AU  - Banoub, J.H.*
AU  - Demian, W.L.*
AU  - Piazzetta, P.*
AU  - Sarkis, G.*
AU  - Kanawati, B.
AU  - Lafont, D.*
AU  - Laurent, N.*
AU  - Vaillant, C.*
AU  - Randell, E.*
AU  - Giorgi, G.*
AU  - Fridgen, T.D.*
C1  - 46723
C2  - 37769
SP  - 1717-1732
TI  - The in situ gas-phase formation of a C-glycoside ion obtained during electrospray ionization tandem mass spectrometry. A unique intramolecular mechanism involving an ion-molecule reaction.
JO  - Rapid Commun. Mass Spectrom.
VL  - 29
IS  - 19
PY  - 2015
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: Aerosols play an important role in depositing metals into forest ecosystems. Better understanding of forest aerosols with regard to their metal content and their possible sources is of great significance for air quality and forest health. METHODS: Particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5 ) in aerosols was collected every month for 20 months using moderate-volume samplers in the Dinghushan (DHS) nature reserve in southern China. The concentrations of metals (Al, Cd, Mn, Ni, Pb, and Zn) as well as the Pb isotopic ratios in the PM2.5 samples were measured by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Moderate pollution with aerosol PM2.5 was detected at the DHS nature reserve with the air mass from mainland China being the predominant PM2.5 source. The high enrichment factors (EFs) for the heavy metals Pb, Cd, and Zn, as well as the PM2.5 mass concentrations, coupled with backward trajectory analysis, indicated the anthropogenic origins of the PM2.5 and of the heavy metals in the PM2.5 . The Pb isotopic ratios revealed the contributions from various Pb sources, which varied between seasons. CONCLUSIONS: Industrial emissions and automobile exhaust from the Pearl River Delta (PRD) primarily contributed to the anthropogenic Pb in PM2.5 , although there was occasionally a contribution from coal combustion during the wet season. Pb isotopic ratios analyses are helpful for air quality assessment and Pb source tracing.
AU  - Zhu, X.M.*
AU  - Kuang, Y.-W.*
AU  - Li, J.*
AU  - Schroll, R.
AU  - Wen, D.Z.*
C1  - 46287
C2  - 37461
CY  - Hoboken
SP  - 1403-1410
TI  - Metals and possible sources of lead in aerosols at the Dinghushan nature reserve, southern China.
JO  - Rapid Commun. Mass Spectrom.
VL  - 29
IS  - 15
PB  - Wiley-blackwell
PY  - 2015
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: The ionization of neutral diacylglycerols (DAGs) by electrospray ionization mass spectrometry (ESI-MS) is challenging compared with other lipid classes which possess ionic head group conjugations. Although ESI-MS is the method of choice in lipidomic analysis, it is questionable whether all lipid classes can be efficiently ionized by this method. Actually, various lipids were not efficiently detected (due to poor ionization) in many studies which claimed to comprehensively describe lipid profiles. Since neutral lipids are precursors for the biosynthesis of most other lipid classes, the necessity for improved or alternative ionization and identification schemes becomes obvious. METHODS: We identified the 1,2-diacylglycerol (DAG) dimer ion formation in the gas phase by ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) in negative electrospray ionization ((-)ESI) mode. The geometry of the dimer ion was investigated by accurate density functional theory (DFT) calculations at the B3LYP/6-311+G(d)//B3LYP/LANL2DZ level of theory. Fragmentation of the dimer ions of many investigated DAGs has been achieved via collision-induced dissociation (CID) experiments with several elevated collision energies (0-12 eV). RESULTS: We revealed the possibility to ionize neutral DAGs as dimer ions in the negative ESI mode. Quantum mechanical calculations revealed a polar head-to-head intermolecular interaction between one charged DAG and one DAG neutral. This represents an energy minimum structure for the DAG dimer ions. We could furthermore detect CID fragmentation product ions that can only result from intermolecular reactions in this head-to-head conformation (SN2 nucleophilic substitution reactions inside the dimer DAG ion). CONCLUSIONS: Here, we present for the first time the opportunity to ionize and identify DAGs as dimer ions. This new finding provides a new alternative for investigations of important diacylglycerol lipids and provides the opportunity to obtain complementary and more comprehensive results in future lipidomic studies. Copyright © 2014 John Wiley & Sons, Ltd.
AU  - Müller, C.
AU  - Kanawati, B.
AU  - Rock, T.
AU  - Forcisi, S.
AU  - Moritz, F.
AU  - Schmitt-Kopplin, P.
C1  - 31715
C2  - 34688
CY  - Hoboken
SP  - 1735-1744
TI  - Dimer ion formation and intermolecular fragmentation of 1,2-diacylglycerols revealed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for more comprehensive lipid analysis.
JO  - Rapid Commun. Mass Spectrom.
VL  - 28
IS  - 15
PB  - Wiley-blackwell
PY  - 2014
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: A challenge of atmospheric particulate matter (PM) analysis is the understanding of the sources and chemistry of complex organic aerosols, especially the water-soluble organic compounds (WSOC) fraction, a key component of atmospheric fine PM (PM2.5 ). The sources of WSOC are not well understood and, thus, the molecular characterization of WSOC is important because it provides insight into aerosol sources and the underlying mechanisms of secondary organic aerosols formation and transformation. METHODS: In this study, molecular characterization of WSOC was achieved using Fourier transform ion cyclotron resonance mass spectrometry. The aromaticity equivalent (Xc ), a new parameter calculated from the assigned molecular formula, is introduced to improve the identification and characterization of aromatic and condensed aromatic compounds in WSOC. Diesel PM (DPM) and atmospheric PM samples were used to study the applicability of the proposed method. RESULTS: Threshold values of Xc ≥2.5000 and Xc ≥2.7143 are proposed as unambiguous minimum criteria for the presence of aromatics and condensed aromatics, respectively. By using these criteria, 36% of precursors were defined as aromatics and condensed aromatics in the DPM. For comparison, 21% of aromatic and condensed aromatic compounds were defined using the Aromaticity Index (AI) classification. The lower estimates by the AI approach are probably due to the failure to recognize aromatics and condensed aromatics with longer alkyl chains. The estimated aromatic and condensed aromatic fractions in the atmospheric aerosol samples collected in an industrial area affected by biomass burning events were 51.2 and 50.0%, respectively. CONCLUSIONS: The advantage of employing this parameter is that Xc would have a constant value for each proposed core structure regardless of the degree of alkylation, and thus visual representation and structural interpretations of the spectra become advantageous for characterizing and comparing complex samples. In addition, the proposed parameter complements the AI classification and identification of aromatic and condensed aromatic structures in complex matrices.
AU  - Yassine, M.M.*
AU  - Harir, M.
AU  - Dabek-Zlotorzynska, E.*
AU  - Schmitt-Kopplin, P.
C1  - 32537
C2  - 35113
CY  - Hoboken
SP  - 2445-2454
TI  - Structural characterization of organic aerosol using Fourier transform ion cyclotron resonance mass spectrometry: Aromaticity equivalent approach.
JO  - Rapid Commun. Mass Spectrom.
VL  - 28
IS  - 22
PB  - Wiley-Blackwell
PY  - 2014
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - RATIONALE: Compound-specific isotope analysis (CSIA) relies on continuous flow combustion of organic substances to CO(2) and N(2) in a miniature reactor to measure (13)  C/(12)  C and (15)  N/(14)  N stable isotope ratios. Accurate analysis is well established for many volatile hydrocarbons. In contrast, compounds which contain hetero and halogen atoms are less volatile and may be more recalcitrant to combustion. METHODS: This study tested carbon and nitrogen isotope analysis of atrazine, desethylatrazine (DEA), dichlobenil and 2,6-dichlorobenzamide (BAM) by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) with multiple reactor tubes of two different kinds (conventional CuO/NiO/Pt and a NiO tube/CuO-NiO reactor prototype). RESULTS: The advantages of the NiO tube/CuO-NiO reactor were the absence of an additional reduction reactor, the possibility of routine reoxidation in nitrogen isotope analysis, and reliable atrazine and DEA measurements over several hundred injections. In contrast, BAM analysis showed good accuracy for carbon, but notable variations in the trueness of nitrogen isotope ratios. Accurate carbon and nitrogen analysis was nevertheless possible by bracketing samples with external compound-specific standards and subsequent offset correction. CONCLUSIONS: We conclude that instrument data should never be taken at its 'face value', but must consistently be validated with compound-specific standards of the respective analytes.
AU  - Reinnicke, S.
AU  - Juchelka, D.*
AU  - Steinbeiss, S.
AU  - Meyer, A.H.
AU  - Hilkert, A.*
AU  - Elsner, M.
C1  - 7407
C2  - 29703
SP  - 1053-1060
TI  - Gas chromatography/isotope ratio mass spectrometry of recalcitrant target compounds: Performance of different combustion reactors and strategies for standardization.
JO  - Rapid Commun. Mass Spectrom.
VL  - 26
IS  - 9
PB  - Wiley-Blackwell
PY  - 2012
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - L-Ascorbic acid and two distinct anomers, namely the α-D-glucopyranosyl and β-D-glucopyranosyl-(1→2)-L-ascorbic acid (stereoisomers), were studied within the scope of collision-induced dissociation (CID) experiments, performed by linear ion acceleration and collision with argon atoms inside a hexapole quadrupole hexapole ion beam guide, which is coupled to an ion cyclotron resonance (ICR) cell with a 12 Tesla magnet for high-resolution measurements. Loss of C(2)H(4)O(2) neutral from the [M-H](-) anion of L-ascorbic acid was observed. Density functional theory (DFT) calculations on the 6-311+G(2d,p)//6-31+G(d) level of theory reveal a new concerted mechanism for an intramolecular gas-phase rearrangement, through which the observed ejected neutral C(2)H(4)O(2) can take place. A similar rearrangement also occurs in the case of α- and β-D-glucopyranosyl-(1→2)-L-ascorbic acid. For the α isomer, only homolytic glycoside fragmentation was observed. For the β isomer, both homolytic and heterolytic glycoside cleavages were possible. The mechanisms behind all observed fragmentation pathways were fully understood by the implementation of accurate DFT calculations. Stereoisomeric differentiation between α and β isomers of the L-ascorbic acid-2-O-glucoside could be revealed by tandem mass spectrometry (MS/MS) experiments and were explained theoretically.
AU  - Kanawati, B.
AU  - von Saint Paul, V.
AU  - Herrmann, C.
AU  - Schäffner, A.
AU  - Schmitt-Kopplin, P.
C1  - 3754
C2  - 27593
SP  - 806-814
TI  - Mass spectrometric stereoisomeric differentiation between α- and β-ascorbic acid 2-O-glucosides. Experimental and density functional theory study.
JO  - Rapid Commun. Mass Spectrom.
VL  - 25
IS  - 6
PB  - Wiley-Blackwell
PY  - 2011
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Natural organic matter (NOM) occurs as an extremely complex mixture of large, charged molecules that are formed by secondary synthesis reactions. Due to their nature, their full characterization is an important challenge to scientists specializing in NOM as well as analytical chemistry. Ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis enables the identification of thousands of masses in a single measurement. A major challenge in the data analysis process of NOM using the FT-ICR MS technique is the need to sort the entire data set and to present it in an accessible mode. Here we present a simple targeted algorithm called the David Mass Sort (DMS) algorithm which facilitates the detection and counting of consecutive series of masses correlated to any selected mass spacing. This program searches for specific mass differences among all of the masses in a single spectrum against all of the masses in the same spectrum. As a representative case, the current study focuses on the analysis of the well-characterized Suwannee River humic and fulvic acid (SRHA and SRFA, respectively). By applying this algorithm, we were able to find and assess the amount of singly and doubly charged molecules. In addition we present the capabilities of the program to detect any series of consecutive masses correlated to specific mass spacing, e.g. COO, H(2), OCH(2) and O(2). Under several limitations, these mass spacings may be correlated to both chemical and biochemical changes which occur simultaneously during the formation and/or degradation of large mixtures of compounds.
AU  - Grinhut, T.*
AU  - Lansky, D.*
AU  - Gáspár, A.
AU  - Hertkorn, N.
AU  - Schmitt-Kopplin, P.
AU  - Hadar, Y.*
AU  - Chen, Y.N.*
C1  - 5956
C2  - 27657
SP  - 2831-2837
TI  - Novel software for data analysis of Fourier transform ion cyclotron resonance mass spectra applied to natural organic matter.
JO  - Rapid Commun. Mass Spectrom.
VL  - 24
IS  - 19
PB  - Wiley-Blackwell
PY  - 2010
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - In order to better understand the chemical diversity of dissolved organic matter (DOM) in iron-rich mine waters, a variety of sediment pore waters was analysed by means of ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A considerable number of the DOM elemental formulae were found to contain sulfur. In a rather simplified experiment, DOM was exposed to sunlight in the presence of dissolved ferric iron, which is common in the oxygenated acidified epilimnetic waters of mine pit lakes. The photochemical alteration of the CHOS (carbon-, hydrogen-, oxygen- and sulfur-containing) compounds was then categorised by following the changes in signal intensity of mass peaks. Nearly 20,000 elemental compositions were identified and sorted into the following categories: totally degraded, partially degraded, not significantly degraded, minor new photoproducts, and newly formed photoproducts. A large proportion of the CHOS compounds were found to be entirely degraded; the degradation ratios exceeded those of the CHO compounds. The pools of totally degraded compounds and those of newly formed products were contrasted with respect to photochemically relevant mass differences. These results indicate that photochemical loss of sulfur-containing low molecular weight compounds can be considered likely. One feasible explanation is the photodegradation of sulfonic acids within the CHOS pool eventually leading to the release of sulfate.
AU  - Herzsprung, P.*
AU  - Hertkorn, N.
AU  - Friese, K.*
AU  - Schmitt-Kopplin, P.
C1  - 4489
C2  - 27658
SP  - 2909-2924
TI  - Photochemical degradation of natural organic sulfur compounds (CHOS) from iron-rich mine pit lake pore waters - an initial understanding from evaluation of single-elemental formulae using ultra-high-resolution mass spectrometry.
JO  - Rapid Commun. Mass Spectrom.
VL  - 24
IS  - 19
PB  - Wiley-Blackwell
PY  - 2010
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Glutaric acid, a common short-chain aliphatic dicarboxylic acid, was investigated in the negative ion mode by subjecting its [M-H](-) ion to collision-induced dissociation (CID) experiments in an infinity ion cyclotron resonance (ICR) cell coupled to a hexapole-quadrupole-hexapole ion guide. A 12 Tesla magnet was used for high-resolution measurements. Two distinctive main pathways were observed in the MS/MS spectrum. The fragmentation pathways were also thoroughly investigated in a density functional theory (DFT) study involving a B3LYP/6-311+G(2d,p)//B3LYP/6-311+G(d,p) level of theory. Elimination of CO(2) from the [M-H](-) ion of the dicarboxylic acid takes place in a concerted mechanism, by which a 1,5 proton shift occurs from the intact carboxyl group to the methylene moiety located in the alpha position relative to the deprotonated carboxyl group. This concerted mechanism stabilizes the terminal negative charge and deprotonates the second carboxylic acid group. Water elimination from the [M-H](-) ion does not take place by means of a simple proton removal from the alpha methylene group - and OH(-) release from the carboxylate group to abstract an additional alpha proton thus leading to the formation of a deprotonated ketene anion. In the case of this dicarboxylic acid, a new mechanism was found for water elimination, which differs from that known for aliphatic monocarboxylic acids. An intramolecular interaction between the deprotonated and the intact carboxyl groups plays a key role in making a new energetically favourable mechanism. The DFT study also reveals that a combined loss of CO2 and H2O in the form of H2CO3 is possible.
AU  - Kanawati, B.
AU  - Schmitt-Kopplin, P.
C1  - 5251
C2  - 28088
SP  - 1198-1206
TI  - Exploring rearrangements along the fragmentation of glutaric acid negative ion: A combined experimental and theoretical study.
JO  - Rapid Commun. Mass Spectrom.
VL  - 24
IS  - 8
PB  - Wiley-Blackwell
PY  - 2010
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Natural organic matter as complex biogeochemical non-repetitive material was investigated with ion mobility mass spectrometry (IMS) and ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) approaches in order to unravel the existence of multiply charged state constituents. Hereby we describe and assign the potential molecular formulae of these doubly charged species, derived from FTICR-MS, and the existence of these species was confirmed via IMS. The parallel application of these powerful techniques enabled the boundaries of the understanding of natural organic matter to be pushed further.
AU  - Gáspár, A.
AU  - Kunenkov, E.V.*
AU  - Lock, R.*
AU  - Desor, M.*
AU  - Perminova, I.*
AU  - Schmitt-Kopplin, P.
C1  - 1331
C2  - 26056
SP  - 683-688
TI  - Combined utilization of ion mobility and ultra-high-resolution mass spectrometry to identify multiply charged constituents in natural organic matter.
JO  - Rapid Commun. Mass Spectrom.
VL  - 23
IS  - 5
PB  - Wiley-Blackwell
PY  - 2009
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Citrate complexes of Mn and Fe, and potentially those of Cu and Zn, are considered as important low molecular mass species in human serum and cerebrospinal fluid (CSF). For example, Mn is supposed to enter the brain under excess exposure as Mn-citrate leading to neurotoxic effects. Mn-citrate has been characterised in human CSF using chromatography and electrophoresis online with inductively coupled plasma mass spectrometry, but not yet with molecular mass spectrometry. Therefore, this study explores the potential of electrospray ionisation (ESI) with selected reaction monitoring (SRM) for the detection of metal-citrate complexes, in particular Mn-citrate. The collision-induced dissociation of precursor ions with various metal:citrate stoichiometries was studied for Mn-citrate, Fe-citrate, Cu-citrate and Zn-citrate. High selectivity was achieved for Mn(II)-citrate even in respect to Fe(III)-citrate which forms isobaric precursor ions. The limit of detection for Mn-citrate was estimated to be around 250 mu g L-1 (referring to the total Mn content in the standard) using flow injection. The sensitivity was sufficient for the determination of Mn-citrate in standard solutions and in an extract of an Mn-citrate-containing supplement. An improved ESI source design is expected to reduce the limits of detection significantly. The developed ESI-SRM method has the potential to provide complementary data for the quality control of current separation methods for metal citrates using element-selective detection, with application to biomedical samples and further matrices.
AU  - Nischwitz, V.
AU  - Michalke, B.
C1  - 1722
C2  - 26280
SP  - 2338-2346
TI  - Electrospray ionisation with selected reaction monitoring for the determination of Mn-citrate, Fe-citrate, Cu-citrate and Zn-citrate.
JO  - Rapid Commun. Mass Spectrom.
VL  - 23
IS  - 15
PB  - Wiley-Blackwell
PY  - 2009
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) was applied to identify boric acid(B degrees)/borate(B-) complexes in a monomolecular model system, composed of aqueous caffeic acid and boric acid/borate solutions in various concentration ratios at pH 9.2. Using negative mode electrospray ionization as a 'soft' ionization technique, clusters of polyborate were detected beside the well-known BL degrees , BL- and BL2- complexes. An algorithm for the detection of boron complexes, based on their accurate mass and isotope patterns, is proposed which enabled the assignment of elemental compositions/structural formulae of boron/ligand complexes. We present experimental evidence of self-oligomerization of up to six borate units with caffeic acid, resulting in stable covalently bound polyborate-polyol complexes.
AU  - Gáspár, A.
AU  - Harir, M.
AU  - Lucio, M.
AU  - Hertkorn, N.
AU  - Schmitt-Kopplin, P.
C1  - 3323
C2  - 25827
SP  - 3119-3129
TI  - Targeted borate complex formation as followed with electrospray ionization Fourier transform ion cyclotron mass spectrometry: Monomolecular model system and polyborate formation.
JO  - Rapid Commun. Mass Spectrom.
VL  - 22
IS  - 20
PB  - Wiley-Blackwell
PY  - 2008
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Stable isotope ratios ((13)C/(12)C and (15)N/(14)N) were measured in royal jelly (RJ) samples by isotope ratio mass spectrometry (IRMS) to evaluate authenticity and adulteration. Carbon and nitrogen isotope contents (given as delta values relative to a standard, delta(13)C, delta(15)N) of RJ samples from various European origins and samples from commercial sources were analyzed. Uniform delta(13)C values from -26.7 to -24.9 per thousand were observed for authentic RJ from European origins. Values of delta(15)N ranged from -1.1 to 5.8 per thousand depending on the plant sources of nectars and pollen. High delta(13)C values of several commercial RJ samples from -20.8 to -13.3 per thousand indicated adulteration with high fructose corn syrup (HFCS) as a sugar source. Use of biotechnologically produced yeast powder as protein source for the adulterated samples was assumed as delta(15)N values were lower, as described for C(4) or CAM plant sources. RJ samples from authentic and from adulterated production were distinguished. The rapid and reliable method is suitable for urgent actual requirements in food monitoring.
AU  - Stocker, A.
AU  - Rossmann, A.*
AU  - Kettrup, A.
AU  - Bengsch, E.
C1  - 2746
C2  - 23466
SP  - 181-184
TI  - Detection of royal jelly adulteration using carbon and nitrogen stable isotope ratio analysis.
JO  - Rapid Commun. Mass Spectrom.
VL  - 20
IS  - 2
PB  - Wiley
PY  - 2006
SN  - 0951-4198
ER  - 

TY  - JOUR
AU  - Cataldi, T.R.I.*
AU  - Bianco, G.*
AU  - Frommberger, M.
AU  - Schmitt-Kopplin, P.
C1  - 4111
C2  - 21882
SP  - 1341-1344
TI  - Direct analysis of selected N-acryl-l-homoserine lactones by gas chromatography/mass spectrometry.
JO  - Rapid Commun. Mass Spectrom.
VL  - 18
PB  - Wiley
PY  - 2004
SN  - 0951-4198
ER  - 

TY  - JOUR
AU  - Zimmermann, R.
AU  - Ferge, T.
AU  - Galli, M.*
AU  - Karlsson, R.*
C1  - 9877
C2  - 20894
SP  - 851-859
TI  - Application of single-particle laser desorption/ionization time-of-flight mass spectrometry for detection of polycyclic aromatic hydrocarbons from soot particles orginating from an industrial combustion process.
JO  - Rapid Commun. Mass Spectrom.
VL  - 17
PB  - Wiley
PY  - 2003
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - A systematic study was performed to identify the origin of surprisingly high analyte-to-matrix yield ratios recently observed in time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis of oligo- and polypeptides mixed in matrices of alpha-cyano-4-hydroxycinnamic acid (4HCCA). Several sets of samples of porcine insulin in 4HCCA (1:3100 molar) were prepared from liquid solutions by a nebuliser technique, with more than one order of magnitude variation in sprayed material (substrate silicon). Following different periods of storage in air and/or vacuum as well as exposure to high-purity water, TOF-SIMS analysis was performed under oblique impact of 22 keV SF5+. Treatment with water involved either deposition of a droplet covering the whole sample for times between 1 and 20 min or spraying with water in droplet equivalent quantities. The analyte and matrix molecules were detected as protonated molecules (insulin also in doubly protonated form). Even the as-prepared samples usually showed insulin-to-4HCCA yield ratios exceeding the molar ratio of the mixed material. Upon ageing in vacuum the matrix ion yields remained constant but the analyte yields decreased, partly due to break-up of intrachain disulfide bonds. Water treatment resulted in a pronounced decrease in the 4HCCA yield, typically by a factor of five, in parallel with an increase of the insulin yield, by up to a factor of four. Evidence is provided that these changes occur concurrently with a partial dissolution of 4HCCA at the sample surface. The enhanced insulin yield was not correlated with the Na+ yield. The typically 20-fold increase in the insulin-to-4HCCA yield ratio, generated by water exposure of the samples, provides the explanation for the high yield ratios observed previously with water-treated samples. Spraying with water or repeated exposure to water droplets caused a pronounced degradation of the insulin parent yields in combination with an increasing appearance of signals due to the B- and A-chains of insulin. To clarify the issue of surface segregation, a few samples were prepared by spraying acetone-diluted solutions of insulin on previously deposited layers of 4HCCA. Whereas the insulin yields from as-prepared samples were rather low, the yields observed after water treatment were comparable with those observed with samples of insulin in 4HCCA. The results suggest that a large amount of insulin is present at the surface of samples prepared from liquid mixtures of insulin in 4HCCA. With both methods of sample preparation, however, high secondary ion yields of insulin were only obtained after exposure of the samples to water. The chemical changes responsible for this beneficial effect still need to be identified.
AU  - Szymczak, W.
AU  - Wittmaack, K.
C1  - 9876
C2  - 20439
SP  - 2025-2033
TI  - Effect of water treatment on analyte and matrix ion yields in matrix-assisted time-of-flight secondary ion mass spectrometry : The case of insulin in and on hydroxycinnamic acid.
JO  - Rapid Commun. Mass Spectrom.
VL  - 16
PB  - Wiley
PY  - 2002
SN  - 0951-4198
ER  - 

TY  - JOUR
AB  - Mobile resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) was applied for on-line detection of surrogates for polychlorinated dibenzo-p-dioxins/furans (PCDD/F) in the flue gas of an industrial hazardous waste incineration plant (thermal power: 22 MW). Conventional gas chromatography/mass spectrometry (GC/MS) measurements have been performed to establish an indicator relation between the best suited surrogate (monochlorobenzene) and the PCDD/F concentration in the flue gas (measured in international toxicity equivalents, I-TEQ). The indicator relation allows the estimation of the actual PCDD/F emission from the on-line registered MCBz signal. Furthermore, several other aromatic components have been measured on-line. During transient instabilities of the combustion conditions, e.g. due to barrel uptake, highly dynamic changes in the emission profiles of substituted benzenes and polycyclic aromatic hydrocarbons (PAH) were observed.
AU  - Zimmermann, R.
AU  - Heger, H.-J.
AU  - Blumenstock, M.
AU  - Dorfner, R.
AU  - Schramm, K.-W.
AU  - Boesl, U.*
C1  - 20836
C2  - 18892
SP  - 307-314
TI  - On-line measurement of chlorobenzene in waste incineration flue gas as a surrogate for the emission of polychlorinated dibenzo-p-dioxins/furans (I-TEQ) using mobile resonance laser ionization time-of-flight mass spectrometry.
JO  - Rapid Commun. Mass Spectrom.
VL  - 13
PY  - 1999
SN  - 0951-4198
ER  -