Instrumental Analytical Chemistry

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New Articles Published:

 

O. Knoop, M. Woermann, H.V. Lutze, B. Sures, T.C. Schmidt
Ecotoxicological effects prior to and after the ozonation of tamoxifen

Journal of Hazardous Materials, 358 (108), 286-93  (Free access till 05 Sep 2018)

Abstract
The endocrine disrupting micropollutant tamoxifen can induce several effects on aquatic organisms. It is introduced into the environment mainly by wastewater treatment plant effluents. To reduce the discharge of micropollutants into surface waters, ozonation can be used as additional wastewater treatment option. For only few transformation products (TPs) formed by ozonation ecotoxicological data are available. To enable an initial estimation of ecotoxicological potentials of the TPs formed after the ozonation of tamoxifen, acute toxicity (immobilization) to Daphnia magna and green algae growth inhibition using Desmodesmus subspicatus were determined for several ozone doses spiked at pH 3 and pH 7. The initial immobilization of D. magna by tamoxifen was not further observed after ozonation. In contrast, the green algae growth inhibition increased due to ozonation of tamoxifen. Overall, five transformation products were observed. For three TPs, positive correlations of green algae growth inhibition and peak area were determined, whereas two TPs do not induce the residual effects. Based on our observations, TP 270 can be assumed as most potent of the formed TPs concerning green algae growth inhibition. Since the effect is not induced by formed N-oxides, green algae growth inhibition could be reduced by sufficient ozone exposure during wastewater treatment.
 

A.R. Ribeiro, B. Sures, T.C. Schmidt
Cephalosporin antibiotics in the aquatic environment: A critical review of occurrence, fate, ecotoxicity and removal technologies
Environmental Pollution 241(2018), 1153-66 (Free access till 01 Sep 2018)

Abstract

Due to their widespread occurrence in the aquatic environment, human and veterinary cephalosporin antibiotics have been studied as water pollutants. In order to characterize environmental risks of this compound class, this review evaluates relevant data about physicochemical properties, occurrence, ecotoxicity and degradation of cephalosporins. Although application of cephalosporins is rather low compared to other antibiotics and their environmental life-time is believed to be short (i.e. days), the available data is insufficient to draw conclusions on their environmental relevance. Few studies concerning the fate of cephalosporins in soil are available, while hydrolysis and photo-degradation are suggested as the main attenuation processes in the aquatic environment. Cephalosporins have been detected in different aqueous matrices in concentrations ranging from 0.30 ng L−1 to 0.03 mg L−1, with sewage and wastewater being the main matrices with positive findings. For wastewater treatment purposes, several technologies have been tested for the abatement of cephalosporins, including photolysis and adsorption. In most cases, the technology employed led to complete or significant removal (>95%) of parental drugs but few authors reported on cephalosporins' metabolites and transformation products. Furthermore, the present ecotoxicological data are insufficient for comprehensive ecological risk quotient calculations. Considering the total of 53 cephalosporins, effective values (EC, LC, NOAEC, NOAEL, etc.) are only available for around 30% of parental drugs and are very scarce for cyanobacteria, which is considered to be the most sensitive group of organisms to antibiotics. Furthermore, it has been demonstrated that cephalosporins' transformation products can be more toxic and more persistent than the parental drugs. Few investigations considering this possibility are available. Consequently, more effort on ecotoxicological data generation and verification of biological inactivation of cephalosporins-related products is needed. Likewise, the lack of natural depletion rates and knowledge gaps on mixture effects for cephalosporins’ degradation and toxicity have to be overcome.
 

A. Barion, P. Balsaa, F. Werres, U. Neuhaus, T.C. Schmidt
Stability of organochlorine pesticides during storage in water and loaded SPE disks containing sediment
Chemosphere, 210 (2018), 57-64 (Free access till 23 Aug 2018)

Abstract
With regard to the Water Framework Directive (WFD) and the required investigation of the whole water sample including suspended particulate matter (SPM), a storage stability study was conducted to determine the suitable storage time and conditions of 21
organochlorine pesticides (OCPs) spiked in water samples and pre-concentrated on solid-phase extraction disks (SPE disks). Furthermore, this work demonstrates the behaviour of three different certified sediment
reference materials (CRMs) contaminated with OCPs in water samples as well as loaded on SPE disks under different temperature conditions and storage time periods. Extracts collected on SPE disks were stored for 3, 14 and 30 days at both 4 °C and −18 °C in darkness covered in (a) freezer bags and (b) aluminum foil. With few exceptions the results of these tests demonstrate stability of OCPs up to 30 days at −18 °C. The recoveries for most substances range between 84% and 133%. Furthermore, the stability of OCPs in water samples additionally spiked with CRM up to 500 mg and stored at a temperature of 4 °C in darkness up to 56 days was investigated. The addition of
sodium azide enhanced the stability of some substances during storage, especially the endosulfans (I, II) but most substances were stable regardless of sodium azide addition over the entire storage period. An important conclusion of this study is that the storage of loaded SPE disks is an appropriate alternative to storing water samples.

 

Sina Dobaradaran, Torsten C. Schmidt, Iraj Nabipour, Nahid Khajeahmadi, Saeed Tajbakhsh, Reza Saeedi, Mohammad Javad Mohammadi, Mozhgan Keshtkar, Maryam Khorsand, Fatemeh Faraji Ghasemi
Characterization of plastic debris and association of metals with microplastics in coastline sediment along the Persian Gulf
Waste Management 78(2018), 649–58  (Free access till 05 Aug 2018)

Abstract
This study reports number, size and color distribution, and metal contents of microplastics as well as adherent sediments along the Persian Gulf. Samples were collected from 9 stations in summer 2015 with a sampling time interval of 10 days. Plastic size of 2–5 mm, and ≤0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% had the highest abundance considering number per m2, respectively. In general, the majority of collected plastics (79%) were smaller than 5 mm (defined size for microplastics). The mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of plastic fragments were 115, 531, 32.2, 0.035, 0.915, 2.03, 4.59, and 3.6 μg g−1, respectively while the mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of sediments were 186, 3050, 127, 0.81, 5.01, 14.5, 48.6 and 5.43 μg g−1 respectively. There were significant differences between the abundance of plastic items as well as the all examined metal concentrations of microplastics and sediments at different sampling times. As there is no regular cleanup program in the studied areas, significant differences between plastic items number at different sampling times (with higher plastic items number at the first day of sampling) showed that a large number of plastic items may enter from beaches to the sea and become available to marine organisms.

 

Torsten C. Schmidt
Recent trends in water analysis triggering future monitoring of organic micropollutants
Analytical and Bioanalytical Chemistry 410(17) 2018, 3933–41

Abstract
Water analysis has been an important area since the beginning of analytical chemistry. The focus though has shifted substantially: from minerals and the main constituents of water in the time of Carl Remigius Fresenius to a multitude of, in particular, organic compounds at concentrations down to the sub-nanogram per liter level nowadays. This was possible only because of numerous innovations in instrumentation in recent decades, drivers of which are briefly discussed. In addition to the high demands on sensitivity, high throughput by automation and short analysis times are major requirements. In this article, some recent developments in the chemical analysis of organic micropollutants (OMPs) are presented. These include the analysis of priority pollutants in whole water samples, extension of the analytical window, in particular to encompass highly polar compounds, the trend toward more than one separation dimension before mass spectrometric detection, and ways of coping with unknown analytes by suspect and nontarget screening approaches involving high-resolution mass spectrometry. Furthermore, beyond gathering reliable concentration data for many OMPs, the question of the relevance of such data for the aquatic system under scrutiny is becoming ever more important. To that end, effect-based analytics can be used and may become part of future routine monitoring, mostly with a focus on adverse effects of OMPs in specific test systems mimicking environmental impacts. Despite advances in the field of water analysis in recent years, there are still many challenges for further analytical research.

Jahresbericht 2017 der IAC

Der Jahresbericht 2017 der Instrumentellen Analytischen Chemie ist fertig gestellt und steht zum Download bereit.

New Articles Published:

A.R. Ribeiro, H.V. Lutze, T.C. Schmidt
Base-catalyzed hydrolysis and speciation-dependent photolysis of two cephalosporin antibiotics, ceftiofur and cefapirin
Water Research 134(2018), 253-60

Abstract
Lately, special attention has been given to veterinary cephalosporin antibiotics due to their broad activity spectrum and significant consumption. Indeed, the determination of hydrolytic and photolytic kinetics provides a better comprehension of the undesired persistence of cephalosporins in aqueous matrices. In this work, the two widely used veterinary antibiotics ceftiofur (CEF) and cefapirin (CEPA) showed high instability under alkaline conditions, degrading in few minutes at pH > 11. In buffered solutions at neutral pH and natural temperature (T = 22 ± 1 °C), both drugs presented moderate stability (t½ = 3 d, CEPA and 1.4 d, CEF). Our study also demonstrated that CEPA and CEF speciation did not significantly influence the direct photolysis rates. Using a simulated water disinfection set-up (λ = 254 nm), all ionic species of CEF and CEPA presented fast and similar pseudo-first order degradation rates, kapp 0.0095 ± 0.0004 and 0.0092 ± 0.001 cm2 mJ-1, respectively. Furthermore, using surface water in hydrolysis experiments, CEF demonstrated significant matrix-dependent stability with a half-life (t½ = 14.7 d) tenfold higher than in buffered solutions. In contrast, CEPA presented a very similar hydrolysis rate in river water (t½ = 4.2 d) and a subtle faster photo-degradation rate in this same matrix (kapp 0.0128 ± 0.001 cm2 mJ-1), highlighting the importance of disinfection radiation for cephalosporin depletion in aqueous environments.

G. Renner, T.C. Schmidt, J. Schram
Analytical methodologies for monitoring micro(nano)plastics: Which are fit for purpose?
Current Opinion in Environmental Science & Health 1 2018, 55-61(55-61)

Abstract

Image for unlabelled figure

Since 2004, when microplastics appears in literature, thousands of researchers focussed on this topic and analysed microplastics in almost every environmental compartment. However, there is still a lack of standardisation, and therefore, used methodologies varied widely. Most researchers performed controversially discussed visual examination, but it became more and more a supporting tool to reduce measuring effort. To that account, especially infrared or Raman microscopy were used for chemical characterisation. This indicates that dimensions of analysed microplastics changed to micrometre scaling. However, those microscopy technologies were used for particle by particle characterisation, and therefore, it is still challenging to handle the mass of data. Alternatively, thermal extraction and desorption gas chromatography is a useful integrating analysis approach, which allows a multicomponent characterisation of environmental samples without any complex sample preparation.
 

H.L. Wiegand, C.T. Orths, K. Kerpen, H.V. Lutze, T.C. Schmidt
Investigation of the Iron–Peroxo Complex in the Fenton Reaction: Kinetic Indication, Decay Kinetics, and Hydroxyl Radical Yields
Environmental Science & Technology 51(24) 2017, 14321-9
DOI: 10.1021/acs.est.7b03706

Abstract
Abstract Image
The Fenton reaction describes the reaction of Fe(II) with hydrogen peroxide. Several researchers proposed the formation of an intermediate iron–peroxo complex but experimental evidence for its existence is still missing. The present study investigates formation and lifetime of this intermediate at various conditions such as different Fe(II)-concentrations, absence vs presence of a hydroxyl radical scavenger (dimethyl sulfoxide, DMSO), and different pH values. Obtained results indicate that the iron–peroxo complex is formed under all experimental conditions. Based on these data, stability of the iron–peroxo complex could be examined. At pH 3 regardless of [Fe(II)]0 decay rates for the iron–peroxo complex of about 50 s–1 were determined in absence and presence of DMSO. Without DMSO and [Fe(II)]0 = 300 μM variation of pH yielded decay rates of about 70 s–1 for pH 1 and 2 and of about 50 s–1 at pH 3 and 4. Hence, the iron–peroxo complex becomes more stable with increasing pH. Furthermore, pH-dependent hydroxyl radical yields were determined to investigate whether the increasing stability of the intermediate complex may indicate a different reaction of the iron–peroxo complex which might yield Fe(IV) instead of hydroxyl radical formation as suggested in literature. However, it was found that hydroxyl radicals were produced proportionally to the Fe(II)-concentration.

F. Itzel, K.S. Jewell, J. Leonhardt, L.Gehrmann, U. Nielsen, T.A. Ternes, T.C. Schmidt, J. Türk
Comprehensive analysis of antagonistic endocrine activity during ozone treatment of hospital wastewater
Science of The Total Environment 624(2018), 1443-54

Abstract
To reduce the discharge of micropollutants, advanced wastewater treatment methods were investigated in the last years. Estrogenic effects were found to be reduced by ozonation. These activities are usually measured using genetically modified cell-based tests. As these bioassays are representing a sum parameter, also inhibitory effects such as antagonistic effects need to be further investigated as they are potentially reducing the detected activities. Therefore, a direct comparison of chemical target analysis and biological equivalent concentrations measured by bioassays is often difficult. To investigate the fate of antagonistic activities and their role in mixtures with agonistic activities, two hospital wastewater treatment plants were studied after different treatment steps. Thereby highly enriched samples were analyzed by a combination of bioassays with chemical target and non-target analyses. In order to achieve an in-depth characterization of the antagonistic activities a fractionation of the enriched samples was performed. To identify relevant compounds an effect directed identification approach was used by combining high-resolution mass spectrometry and bioassays. The results showed a high reduction for estrogene and androgene activities. However, a constant antagonistic activity after membrane bioreactor and ozone treatment was observed. A reduction of the antagonistic activity was observed after passing an activated carbon filter. The fractionation approach showed a specific finger-print of each sample of the different treatment steps. Hereby we could show that the composition of agonistic and antagonistic active compounds is changing after each treatment step while the overall measured activity stays the same. Using fractionation and the combination of bioassays the number of relevant features detected by chemical non-target screening could be reduced by > 85%. As a result the phosphorous flame retardant TCEP could be identified as anti-estrogene active. Future research should be done to identify more antagonistic active compounds and potentially active transformation products after ozone treatment.

 

H.V. Lutze, J. Brekenfeld, S.Naumov, C. von Sonntag, T.C. Schmidt
Degradation of perfluorinated compounds by sulfate radicals – New mechanistic aspects and economical consideration
Water Research 129(2018), 509-19

Abstract
Perfluorinated organic compounds (PFC) are an important group of pollutants, which are difficult to be degraded in conventional water treatment. Even hydroxyl radical based processes are not capable to degrade these compounds. Sulfate radicals can oxidize a group of PFC, i.e., perfluorinated carboxylic (PFCAs) acids. However, information in literature on kinetics and reaction mechanism is largely based on model simulations which are prone to errors. The present study provides mechanistic insights based on product formation, material balances, competition kinetics experiments and quantum chemical calculations. Furthermore, energy requirements for sulfate radical based degradation of PFCA is evaluated in the present study. PFCAs can be partly mineralized in chain reactions initiated by sulfate radicals (SO4). The perfluorinated acetic acid (TFA), propionic acid, and butanoic acid are largely degraded in a primary reaction with sulfate radicals. In case of PFCA with a chain length of > 4 carbons low yields of PFCA products were observed. Regarding reaction kinetics sulfate radicals react very slow with PFCAs (≈ 104 M−1 s−1). Thus, the energy demand required for generation of SO4 by photolysis of S2O82─ (UV/S2O82−) is very high. A 90% degradation of a PFCA by UV/S2O82− was estimated to be 55 kW h m−3 in pure water.

Mülheim Water Award 2018 open for application

The Mülheim Water Award 2018 will open for application on 1st December 2017. The Award is endowed with EUR 10.000, sponsored jointly by RWW Rheinisch-Westfälische Wasserwerksgesellschaft and GERSTEL, and coordinated by IWW Water Centre. The Mülheim Water Award aims at applied research and development projects as well as the implementation of innovative concepts for drinking water supply and water analysis.

Topic of the current submission is: "Innovations for water systems and water analysis for sustainable water management and safe and secure drinking water supply". Application deadline is February 28, 2018.

Natural or legal persons, groups of persons or institutions from Europe may apply for the Mülheim Water Award with projects delivering innovative procedures, solutions, products and concepts. Wanted for application are innovative, practice-orientated concepts as well as ready-for-use solutions to meet future challenges in water systems and water analysis.

The application procedure: Interested parties initially submit a short application. The application form will be available until February 28, 2018 at www.muelheim-water-award.com. From the pool of submitted applications, the jury will identify the most promising candidates, and will request information that is more detailed. Candidates selected for this second stage have good chances for the Mülheim Water Award 2018.

The Mülheim Water Award was first granted in 2006. In five competition rounds, more than 100 applications from 20 different European countries were submitted, covering the entire range of water management topics.

For more information visit www.muelheim-water-award.com.

Contact

Coordinating office of the Mülheim Water Award
c/o IWW Rheinisch-Westfälisches Institut für Wasser Beratungs- und Entwicklungsgesellschaft mbH
Peter Lévai
Moritzstraße 26
45476 Mülheim an der Ruhr
Germany

Phone: +49 208 40303-435
Fax: +49 208 40303-80
E-Mail: info@muelheim-water-award.com
Internet: www.muelheim-water-award.com

New Articles Published:

A.R. Ribeiro, B. Sures, T.C. Schmidt

Ecotoxicity of the two veterinarian antibiotics ceftiofur and cefapirin before and after photo-transformation
Science of The Total Environment 619–620(2018), 866–73

Abstract
The release of antibiotics into the environment may lead to deleterious effects in non-target organisms as well as pressure in antimicrobial resistance acquirement. Ceftiofur (CEF) and cefapirin (CEPA) are veterinary cephalosporins used for recurrent and economically relevant infections. Both antibiotics have been detected in aquatic environments and their fate during drinking water processing is still unknown. This work investigated the acute and chronic toxicities of CEF and CEPA towards aquatic organisms including stability tests. Complementary, the effects of water disinfection radiation (UV-C, 254 nm) on ecotoxicological responses were studied. CEF and CEPA have significant decay during Daphnia magna tests, portraying half-lives (t1/2) of 49 and 53 h, respectively. During tests with green algae (Scenedesmus spec.), CEPA was more instable (t1/2 88 h) than CEF (t1/2 267 h). CEF and its presumable hydrolysis products induced deleterious effects in Daphnia magna (48 h EC50 139, LC50 179 in μM), which was not observed with Scenedesmus spec. (72 h NOAEC 82.5 ± 2.5 μM). In the case of CEPA, no toxic effects were observed in either test (48 h EC-LC50 > 510 and 72 h NOAEC 57 ± 6, in μM). Photolysis of CEPA resulted in toxic products, which were effective for the cladoceran but not for the green algae. On the other hand, the different radiation doses studied did not affect CEF ecotoxicity. This investigation illustrates the importance of cephalosporin hydrolysis during standard toxicity tests. Furthermore, the potential formation of species-specific toxic compounds during water processing is demonstrated, highlighting the need of further assessing toxicity of both cephalosporins and their transformation products.

 

O. Knoop, F. Itzel, J. Tuerk, H.V. Lutze, T.C. Schmidt
Endocrine effects after ozonation of tamoxifen
Science of The Total Environment 622–623(2018), 71–8

Abstract
Ozonation is used as additional wastewater treatment option to remove recalcitrant micropollutants. It also removes the estrogenic activity found in wastewater but not always the anti-estrogenic activity. This can be explained by an incomplete removal of anti-estrogenic micropollutants or by formation of transformation products (TPs) which retain the activity. The present study investigates the degradation of the anti-estrogenic pharmaceutical tamoxifen in pure water, regarding TP formation and related anti-estrogenic effect using Arxula adeninivorans yeast estrogen screen (A-YES). In total, five transformation products were detected: three N-oxides and two further products (TP 270 and TP 388). For the transformation product TP 270 a correlation of the extent of formation with an increase of the anti-estrogenic activity was determined, demonstrating that transformation products from ozonation can be more active in a bioassay than the parent compounds. Our study shows also that the transformation of tamoxifen to N-oxides reduces the anti-estrogenic activity. The reactivity of amines towards ozone typically increases with pH, since only deprotonated amines react with ozone. Hence, removal of the endocrine activity by N-oxide formation may be disfavored at low pH.

E. Reisz, C. von Sonntag, A. Tekle-Röttering, S. Naumov, W. Schmidt, T.C. Schmidt:
Reaction of 2-propanol with ozone in aqueous media

Water Research, 128 (2018), 171-82

Abstract
This paper deals with reactions occurring in the aqueous system of 2-propanol/ozone. The considered reactions are discussed from thermodynamic and kinetic points of view. The major finding refers to the fact that 2-propanol reacts with O3 mainly via hydride transfer:

(HO)(H3C)2CH + O3 → [(HO)(H3C)2C+ + HO3]cage → (HO)(H3C)2C+ + HO3 → (H3C)2CO + H2O + O2

Arguments supporting this proposed mechanism are: high exergonicity of reaction (ΔG = −234 kJ mol−1 for the first two steps), low HO yield - (2.4 ± 0.5)% and high acetone yield - (87.2 ± 1.5)%. Other oxidation products detected within the system are acetaldehyde - (1.4 ± 0.1)%, formaldehyde - (4.0 ± 0.1)%, acetic acid - (2.8 ± 0.2)%, formic acid - (0.6 ± 0.2)% and hydrogen peroxide - (1.5 ± 0.1)%. The temperature dependence of the second order rate constant for the reaction 2-propanol + O3 → products is ln kII = 29.64–8500 × T−1. The activation energy and pre-exponential factor derived from this relationship are (71 ± 3) kJ mol−1 and (7.5 ± 6.4) × 1012 M−1 s−1, respectively. At 23 °C, the second order rate constant is kII = (2.7 ± 0.1) M−1 s−1. The low reaction rate can be explained by the transfer of one hydride ion from 2-propanol to electrophilic ozone.

S. Wacławek, H.V. Lutze, K. Grübel, V.V.T. Padil, M. Černík, and D.D.Dionysiou:
Chemistry of persulfates in water and wastewater treatment: A review
Chem. Eng. J., 2017. 330(Supplement C): p. 44-62.

Neues ZIM-Projekt bewilligt:

Schnelle Vor-Ort-Analytik zur Detektion von Pestiziden in Wässern mittels 2D-Ionenmobilitätsspektrometrie (Hydro-2D-DMS)
Laufzeit: 1.11.2017-31.12.2019

Ziel des Projektes ist die Entwicklung eines kostengünstigen Systems, welches die schnelle Vor-Ort-Analyse von vier der in der WRRL aufgenommenen Substanzen (Quinoxyfen, Cybutryn, Dichlorvos, Terbutryn) als Analyten in Wässern mit unterschiedlichen Matrixbestandteilen unter Einbeziehung der rechtlich geforderten Grenzwerte erlaubt.
Zur Anwendung kommen soll ein Verfahren basierend auf der Technik der differentiellen Ionenmobilitätsspektrometrie. Herkömmlich zur Analyse verwendete DMS-Systeme sind beschränkt auf eine festgelegte Frequenz (ca. 1MHz) der elektrischen Felder. Zur Verbesserung der Leistungsfähigkeit soll im Rahmen dieses Projektes ein Detektor entwickelt werden, der eine Erweiterung des detektierbaren Massenbereiches erlaubt und eine hohe Nachweisempfindlichkeit haben soll. Probeneingabesystem und Ionenquelle sind an das Detektormodul anzupassen. Neben der Konstruktion und des Baus des Prototyps sind Optimierung der experimentellen Parameter, Kalibrierung sowie die Analyse realer Wässer mit unterschiedlicher Zusammensetzung ein weiterer Schwerpunkt des Projektes.

Neues DFG-Projekt bewilligt: „Charakterisierung des Metaboloms von P. aeruginosa im Biofilm als Lungeninfektionsmodell

​​Im Rahmen dieses Projektes wird das Metabolom von P. aeruginosa unter lungenadaptierten Bedingungen als Biofilm charakterisiert. Um dies zu realisieren, soll ein Beprobungssystem für die Anzucht von P. aeruginosa entwickelt werden, welches es erlaubt aus dem Nährmedium, dem Biofilm und dem Dampfraum zeitabhängig Proben zu entnehmen. Der verfolgte Ansatz über das drei-Phasen-System erlaubt es, detektierte und charakterisierte Verbindungen entsprechend als Substrate oder Stoffwechselprodukte einzuordnen. Über verschiedene Extraktionsstechniken soll eine möglichst umfangreiche Anreicherung der gebildeten Metabolite erreicht werden.

Die qualitative und quantitative Bestimmung ausgewählter Metabolite erfolgt mittels GCxGC-EI-MS und LC+LC-IM-qTOF-MS. Die dabei notwendige Methodenentwicklung umfasst die Probenanreicherung und Optimierung relevanter experimenteller Parameter wie zum Beispiel, Auswahl der stationären Phasen, Analysenzeit in der zweiten Dimension (Modulationszeit) und Flussraten.

Durch die Zugabe von Benzothiazol als interner Standard zum Medium soll außerdem die Anreicherung, Diffusion und Verteilung der potentiellen Stoffwechselprodukte zwischen allen drei Phasen simuliert, untersucht und kontrolliert werden.

Anhand der Ergebnisse soll überprüft werden, ob P. aeruginosa über die im Dampfraum detektierten Metabolite repräsentiert wird und so eine Identifizierung von P. aeruginosa ausschließlich über die Dampfraumbeprobung möglich ist.

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In this project, the metabolome of P. aeruginosa will be characterized considering lung adapted conditions by using a biofilm as a lung infection model. Therefore, a sampling system for the cultivation of P. aeruginosa will be developed, which enables the sampling of the culture medium, the biofilm and the headspace over time. This three-phase approach allows the classification of detected and characterized substances as substrates or metabolites. A comprehensive preconcentration of the metabolites shall be achieved by application of various extraction techniques.

The qualitative and quantitative determination of selected metabolites will be carried out by GCxGC-EI-MS and LC+LC-IM-qTOF-MS. The sample preconcentration and experimental parameters e.g. stationary phase, analysis time in the 2nd dimension (modulation time) and flow rates will be optimized. 

As an internal standard, Benzothiazole will be added to the culture medium in order to investigate and control the preconcentration, diffusion and distribution of the potential metabolites.

Based on the results, it shall be verified if P. aeruginosa is represented by detecting only the metabolites in the headspace of a biofilm sample. This should answer the question whether the identification of P. aeruginosa is possible only by head space analysis or not.

 

 

Unikids:
„Wasser baut Brücken, aber hat es auch ein Gedächtnis?“

​​

​Am 8. März 2017 fand die Auftaktveranstaltung der „Unikids“ in diesem Frühjahr statt. 600 Kinder im Alter zwischen 8-12 Jahren erhielten passend zum Thema ein blaues T-Shirt und sahen ein bisschen aus wie Wassertropfen. Gespannt und aufgeregt verfolgten sie eine Stunde lang die Vorlesung von Torsten Schmidt, Ursula Telgheder und Claudia Ullrich zum Thema Wasser unter dem Titel „Wasser baut Brücken, aber hat es auch ein Gedächtnis?“. Mit anschaulichen Beispielen, Filmausschnitten  und eindrucksvollen Experimenten wurden die Eigenschaften von Wasser und ihre Wirkung auf Mensch und Umwelt nahegebracht. 

Unikids 3

​​​Besonders begeistert waren die Kinder von der Wasserbrücke, die zwischen zwei Gefäßen beiAnlegen einer sehr hohen Spannung entsteht und den bei verdunkeltem Hörsaal deutlich sichtbaren Überschlägen. Im zweiten Teil erfuhren die Kinder, warum es so viel  Hokuspokus im Wasserbereich gibt, z. B. das angebliche Wassergedächtnis. An einem einfachen Beispiel wurde ihnen gezeigt, wie sie mit wissenschaftlicher Methodik Unsinn entlarven können.

Unikids 2

Den Kindern hat die Vorlesung sichtlich viel Spaß gemacht, aber auch das Team war begeistert von den aktiven Zuhörern.

 

Neue Auflage erschienen:

Buchcover Analytische Chemie

Die verschiedenen Bücher von Prof. Georg Schwedt zur analytischen Chemie gelten bereits als Klassiker. Dazu trägt das Konzept der Verbindung von Grundlagen, Methoden und Praxis bei, aber auch die hochwertige graphische Gestaltung. Abbildungen aus „dem Schwedt“ finden sich sicherlich in allen Vorlesungen zur analytischen Chemie wieder. Das fundamentale Lehrbuch „Analytische Chemie“ ist im Dezember 2016 nun in der dritten Auflage bei Wiley-VCH erschienen. Alle relevanten Aspekte der Analytischen Chemie werden in diesem Lehrbuch, das gleichzeitig auch als Referenz für Praktiker dient, umfassend und klar auf den Punkt gebracht. Ab dieser Auflage wird das Lehrbuch nicht mehr von Prof. Schwedt alleine verantwortet, sondern unter Beteiligung der beiden Professoren für analytische Chemie an der Universität Duisburg-Essen, Oliver Schmitz und Torsten Schmidt. Die beiden haben in dieser Auflage Kapitel inhaltlich neu gestaltet, für die infolge der methodischen und technologischen Entwicklungen eine Aktualisierung erforderlich war. So wurden von Oliver Schmitz hauptsächlich die Kapitel über Qualitätssicherung, Massenspektrometrie, chromatographische Trennverfahren und elektrophoretische Trennverfahren überarbeitet. Torsten Schmidt hat vor allem das Kapitel zur Probenvorbereitung aktualisiert und das Grundlagenkapitel ergänzt.

ISBN: 978-3-527-34082-8 Link zum Buch bei Wiley-VCH

Neues ZIM-Projekt bewilligt:

Entwicklung eines kombinierten ln-situ-Sanierungs- und Monitoringverfahrens für die Behandlung von Grundwasserschäden (Luft-Untergrund-Kontamination-Erfassung "LUKE")
Laufzeit: 1.10.2016-31.3.2019

Ziel des Projektes ist die Entwicklung eines preiswerten ln-situ-Verfahrens für die Sanierung von mit BTEX kontaminiertem Grundwasser. Hierfür wird ein spezielles Multiparameter-Lanzensystem zur Aufnahme eines Gasinjektionssystems, zur kontinuierlichen Probenahme sowie zur direkten Bestimmung der Parameter pH-Wert, 02-Gehalt, C02- bzw. CH4-Gehalt, Leitfähigkeit und Feuchte im Grundwasserleiter (Aquifer) entwickelt. Hiermit ist sowohl eine Überprüfung der Vitalitätsparameter als auch eine direkte Kontrolle über die Bildung von C02 und CH4 aus Stoffwechselprozessen möglich. Die Sanierung erfolgt durch die reversible Einbringung einer glasfaserverstärkten Polymermembran in den Aquifer, die Sauerstoff auf diffusivem Wege freisetzt. Dieser dient der schadstoffzehrenden Mikrobiologie als Co-Substrat für ihren Stoffwechsel. Gegebenenfalls können über das
Lanzensystem zusätzliche Nährstoffe zugegeben werden. Mit dem System gekoppelt, ist ein modifiziertes FAIMSSpektrometer mit Fernsteuerung, welches eine kontinuierliche Überwachung der Schadstoffkonzentration in den Beobachtungspegeln erlaubt und somit eine schnelle Bewertung der Sanierungseffizienz ermöglicht.

New article published in ABC

Abc 408 23 Cover

New article published in JAAS

Kuklya Jaas 2016 Cover

 

 

A. Kuklya, C. Engelhard, K. Kerpen, Ursula Telgheder, Spectroscopic characterization of a low-temperature plasma ambient ionization probe operated with helium/nitrogen plasma gas mixtures, J. Anal. At. Spectrom., 2016, 31, 1574-1581

http://dx.doi.org/10.1039/C6JA00148C

In this study, a systematic spectroscopic characterization of a low-temperature plasma (LTP) probe operated with He/N2 gas mixtures is carried out. The influence of several experimental parameters (e.g., different He/N2 gas mixtures, discharge voltage, and gas flow rate) on the dielectric-barrier discharge afterglow was studied. It was found that an increase of the nitrogen concentration in the helium discharge gas (to values higher than 0.5% N2) leads to a significant decay of N2+, He, and O emission intensities. At 1% N2 and 99% He, oxygen emission bands were not detectable and intensity of He and N2+ emission bands were reduced by approximately five times compared to features in a 100% He discharge. Interestingly, the opposite trend was observed for NO, OH, and N2 species. Here, increasing the N2 fraction in the discharge gas mixture led to an enhancement of emission intensities. Maximum emission bands intensities of OH, NO, and N2 were detected at N2 concentrations of 0.5, 0.6, and 1.0%, respectively. A further increase of the N2 fraction leads to a decrease of emission intensities for all observed species (OH, NO, N2, He, and N2+). In general, an increase in discharge gas flow rate resulted in a significant increase of NO emission band intensities for all N2/He mixtures tested. However, only a minor effect was observed for N2 emission bands. Increasing the discharge voltage resulted in an increase of emission intensities of all detected species. Combined with spatially resolved investigations of the afterglow, these results are considered helpful to further optimize LTP performance. This is especially important for portable and direct analysis instrumentation, where LTP can be used as the ionization source and lower helium gas consumption is desirable because of cost and availability.

 

 

New article published in Water Research

Ozonation Anilines Graphical Abstract

Tekle-Röttering, A., von Sonntag, C., Reisz, E., vom Eyser, C.,
Lutze, H.V., Türk, J., Naumov, S., Schmidt, W., Schmidt, T.C., 2016. Ozonation of anilines: Kinetics, stoichiometry, product identification and elucidation of pathways. Water Research 98, 147-159

 

Evonik Stipendium für Nerea Lorenzo Parodi

Nerea Lorenzo Parodi erhält durch die Evonik Industries AG ein Stipendium für Ihr Promotionsvorhaben „Aromatische Amine als Biomarker im menschlichem Urin: analytische Methodenentwicklung und epidemiologische Untersuchung“ an der Universität Duisburg-Essen.

Die Evonik Industries AG vergibt 3 Doktorandenstipendien mit dem Ziel der Förderung des hochbegabten wissenschaftlichen Nachwuchses an der Fakultät für Chemie der Universität Duisburg-Essen.

 

Urkunde Stipendium

 

 

Evonik Scholarship for Nerea Lorenzo Parodi

Nerea Lorenzo Parodi was awarded with a scholarship for the realization of her PhD project “Aromatic amines as biomarkers in human urine: analytical method development and epidemiological studies” at the University of Duisburg-Essen by the Evonik Industries AG.

Evonik Industries AG awards three scholarships for the realization of a Doctoral thesis with the objective of promoting highly talented young researchers at the faculty of Chemistry of the University Duisburg-Essen.

 

 

Drei neue ZIM-Projekte bewilligt:

Schnelle Vor-Ort-Analytik zur Detektion von Sulfonamiden in Wässern mittels 2D-Fluoreszenzspektroskopie (MultiDimSpec)
Laufzeit: 1.10.2015-31.3.2018

Ziel des Projektes ist die Entwicklung eines miniaturisierten Systems, welches die schnelle Vor-Ort-Analyse von ausgewählten Sulfonamiden in Wässern mit unterschiedlichen Matrixbestandteilen unter Einbeziehung der rechtlich geforderten Orientierungswerte erlaubt. Als Detektionsmethode wird die 2D-Fluoreszenzspektroskopie eingesetzt, da aufgrund der intensiven Fluoreszenz der Sulfonamide die Sensitivität groß genug ist, um die als Orientierungswerte geforderten Konzentrationen bestimmen zu können. Die notwendige Selektivität wird durch Aufnahme und multivariater Datenanalyse der Emissionsspektren bei unterschiedlichen Anregungswellenlängen erreicht.
Neben dem in der aquatischen Umwelt häufig nachgewiesenen Antibiotikum Sulfamethoxazol werden als weitere lndikatorsubstanzen p-Toluolsulfonamid, o-Toluolsulfonamid, Benzolsulfonamid, Sulfadiazin und Sulfamethazin gewählt.
Der in Laborversuchen getestete Prototyp wird in ein Multisensorsystem integriert und anschließend in Feldstudien erprobt. Neben der Steuerungssoftware sind komplexe Softwaremodule für die Datenauswertung zu erstellen .

Entwicklung eines DIP-APPI-IMS-Systems zur Qualitätskontrolle von chemischen und pharmazeutischen Produkten (DIPPI-IMS)
Laufzeit: 1.7.2015-31.7.2017

Im Fokus des Forschungsvorhabens steht die Entwicklung eines Direct Inlet Probe - Atmospheric Pressure Photoionization – Ion Mobility Spectrometers (DIP-APPI-IMS) als sensitives, kostengünstiges und schnelles Verfahren für die Produkt- und Qualitätskontrolle in der chemischen und pharmazeutischen Industrie. DasProbenaufgabesystem (DIP) ermöglicht das Einbringen und Verdampfen fester und flüssiger Proben. Nach der Vorabtrennung von Matrixbestandteilen, werden die Analyten mittels Photoionisation bei Atmosphärendruck (APPI) ionisiert und innerhalb weniger Millisekunden im miniaturisierten Ionenmobilitätsspektrometer separiert und detektiert. Die Leistungsfähigkeit des DIP-APPI-IMS-Systems wird anhand der Analyse von ausgewählten Wirkstoffen in Tabletten und Salben geprüft. Als Vertreter flüssiger Proben sind unterschiedliche Speiseöle zu analysieren. Als Beispiel für die Oberflächenanalytik von Produkten sollen Weichmacher in Kunststoffen herangezogen werden. 

Entwicklung einer oxidativen Abwasseraufbereitungsmethode auf der Basis von Chlordioxid (ABC)
Laufzeit: 1.7.2015-31.12.2017

Ziel des Projektes ist die Entwicklung einer neuen Abwasseraufbereitungsmethode zur Elimination von Spurenstoffen und Desinfektion durch Chlordioxid. Wegen der hohen Selektivität von Chlordioxid ist das Potenzial zur Bildung unerwünschter Nebenprodukten schwächer ausgeprägt als bei dem zur Zeit diskutierten Einsatz von Ozon zur weitergehenden Abwasserbehandlung.  Zur Realisierung des neuen Oxidationsverfahrens wird ein von a.p.f  Aqua System AG entwickelter Chlordioxidgenerator an die Abwasseranwendung angepasst und im Rahmen einer mehrmonatigen Pilotierungsphase die Langzeitstabilität des Verfahrens ermittelt sowie eine Abschätzung der Kosten dieses Verfahrens durchgeführt.

 

Dr. Holger Lutze und Prof. Dr. Torsten Schmidt

Promotionspreis der Wasserchemischen Gesellschaft für
Dr. Holger Lutze

Dr. Holger V. Lutze (Universität Duisburg-Essen) erhält 2015 den "Promotionspreis auf dem Gebiet der Wasserchemie – gefördert von der Walter-Kölle-Stiftung". Der Vorstand der Wasserchemischen Gesellschaft, eine Fachgruppe in der Gesellschaft Deutscher Chemiker e.V. (GDCh), konnte diese Auszeichnung 2015 aufgrund hervorragender Arbeiten an zwei Kandidaten verleihen.

Dr. Lutze beschäftigt sich in seiner Arbeit "Sulfate radical based oxidation in water treatment"3 mit einem innovativen radikalbasierten Wasseraufbereitungsverfahren zum Abbau persistenter Schadstoffe.

 

Dr. Walter Kölle, der 1971 als erster Wissenschaftler mit dem Fachgruppenpreis der Wasserchemischen Gesellschaft ausgezeichnet wurde, richtete 2010 bei der GDCh eine Stiftung ein, um den wissenschaftlichen Nachwuchs in der Wasserchemie zu fördern. Der Promotionspreis auf dem Gebiet der Wasserchemie – gefördert von der Walter-Kölle-Stiftung - wird für herausragende Dissertationen auf den in der Fachgruppe vertretenen wissenschaftlichen Gebieten verliehen, die mit der Gesamtnote sehr gut oder besser bewertet wurden und eine besondere Leistung für die Weiterentwicklung des Fachgebiets darstellen.

Die Verleihung erfolgt einmal jährlich im Rahmen der Jahrestagung der Wasserchemischen Gesellschaft

Prof. Dr. Stefan Rumann, Prof. Dr. Torsten Schmidt und Prof. Dr. Ute Klammer

Prof. Torsten C. Schmidt unter den Preisträgern der UDE Diversity-Preise 2015

Die Universität Duisburg-Essen feierte am 09. Juni 2015 den 3. bundesweiten Diversity-Tag, in dessen Rahmen auch die Diversity-Preise verliehen wurden. Der Diversity-Engagementpreis ging diesmal an die Fakultät für Chemie: Prof. Bettina Siebers und Prof. Dr. Torsten Schmidt