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Dou Q, Canavan A, Fu Y, Xiang L, Wang Y, Wang X, Jiang X, Dirr C, Wang F, Elsner M. Nitrogen stable isotope analysis of sulfonamides by derivatization-gas chromatography-isotope ratio mass spectrometry. Anal Bioanal Chem 2024:10.1007/s00216-024-05361-2. [PMID: 38849528 DOI: 10.1007/s00216-024-05361-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/15/2024] [Accepted: 05/16/2024] [Indexed: 06/09/2024]
Abstract
The continuous introduction of micropollutants into the environment through livestock farming, agricultural practices, and wastewater treatment is a major concern. Among these pollutants are synthetic sulfonamide antibiotics such as sulfamethoxazole, which are not always fully degraded and pose a risk of fostering antimicrobial resistance. It is challenging to assess the degradation of sulfonamides with conventional concentration measurements. This study introduces compound-specific isotope analysis of nitrogen isotope ratios at natural abundances by derivatization-gas chromatography hyphenated with isotope ratio mass spectrometry (derivatization-GC-IRMS) as a new and more precise method for tracing the origin and degradation of sulfonamides. Here, sulfamethoxazole was used as a model compound to develop and optimize the derivatization conditions using (trimethylsilyl)diazomethane as a derivatization reagent. With the optimized conditions, accurate and reproducible δ15N analysis of sulfamethoxazole by derivatization-GC-IRMS was achieved in two different laboratories with a limit for precise isotope analysis of 3 nmol N on column, corresponding to 0.253 µg non-derivatized SMX. Application of the method to four further sulfonamides, sulfadiazine, sulfadimethoxine, sulfadimidine, and sulfathiazole, shows the versatility of the developed method. Its benefit was demonstrated in a first application, highlighting the possibility of distinguishing sulfamethoxazole from different suppliers and pharmaceutical products.
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Affiliation(s)
- Qingyuan Dou
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Aoife Canavan
- Chair of Analytical Chemistry and Water Chemistry, School of Natural Sciences, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Yuhao Fu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Leilei Xiang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Yu Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Xi Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Xin Jiang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Christopher Dirr
- Chair of Analytical Chemistry and Water Chemistry, School of Natural Sciences, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany
| | - Fang Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, 210008, China.
- University of Chinese Academy of Science, Beijing, 100049, China.
| | - Martin Elsner
- Chair of Analytical Chemistry and Water Chemistry, School of Natural Sciences, Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85748, Garching, Germany.
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de Mendonça Ochs S, Souza TM, Sobrinho RDL, de Oliveira RB, Bernardes MC, Netto ADP. Simultaneous evaluation of benzotriazoles, benzothiazoles and benzenesulfonamides in water samples from the impacted urban Jacarepaguá Lagoon System (Rio de Janeiro, Brazil) by liquid chromatography coupled to electrospray tandem mass spectrometry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:160033. [PMID: 36356777 DOI: 10.1016/j.scitotenv.2022.160033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Benzotriazoles, benzothiazoles, and benzenesulfonamides are emerging pollutants stable in aquatic media emitted by anthropogenic sources. Selected compounds of these classes were evaluated in the impacted urban Jacarepaguá Lagoon System (JLS) located in a tropical coastal region of Rio de Janeiro City, Brazil that has experienced a rapid expansion of urban occupation and environmental degradation in recent decades, and it represents a pioneering study of these compounds carried out in Brazilian areas. A method of solid phase extraction followed by ultra-performance liquid chromatography coupled to electrospray tandem mass-spectrometry was implemented to evaluate water samples collected in different water bodies (rivers, lagoons, and channels) of the JLS from March 2017 to May 2018. Limits of quantification (LOQs) ≤ 10.0 ng L-1, method linearity up to 1000 μg L-1, and recoveries between 62 and 121 % at three different levels were obtained. Individual concentrations varied from < LOQ to 5260 ng L-1 (benzotriazole, in May 2018) which also predominated in all river samples. 2-mercaptobenzothiazole predominated in samples taken in lagoons and channels in March 2017, and 2-aminobenzothiazole was never detected. River samples showed total concentrations up to 30 times larger in all sampling campaigns, except March 2017 when the sample taken at Tijuca Lagoon showed the largest total concentration of the compounds studied due to the largest concentration of 2-mercaptobenzothiazole (2505 ng L-1) found in this study. Principal component analysis (PCA) using only composition data was unable to distinguish samples from rivers, and lagoons and channels, but a PCA combining composition data and environmental parameters (pH, Eh, dissolved O2 concentration, temperature, salinity, and conductivity) discriminated the samples according to two groups: rivers and lagoons and channels. The Joá Channel flows directly to the open sea and our data allowed a (preliminary) estimation of the total mass flows of the studied compounds to the open sea, which would vary between 1702 g day-1 (March 2017) to 106 g day-1 (May 2018) and allowed a preliminary estimative based on the geometric mean of input of 87.9 kg year-1, indicating the importance of the drainage area to the contamination of the coastal area, and consequently to ocean pollution.
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Affiliation(s)
- Soraya de Mendonça Ochs
- FIOCRUZ, Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde - INCQS, Departamento de Química, Avenida Brasil, 4365, Rio de Janeiro, RJ CEP 21040-360, Brazil; Programa de Pós-Graduação em Química, Instituto de Química (PPGQ), Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Valonguinho, Centro, Niterói, RJ CEP 24020-141, Brazil
| | - Thallis Martins Souza
- Programa de Pós-Graduação em Química, Instituto de Química (PPGQ), Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Valonguinho, Centro, Niterói, RJ CEP 24020-141, Brazil; FIOCRUZ, Fundação Oswaldo Cruz, Instituto de Tecnologia em Imunobiológicos (Bio-Manguinhos), Departamento de Controle de Qualidade, Rio de Janeiro, RJ, Brazil
| | - Rodrigo de Lima Sobrinho
- Programa de Pós-Graduação em Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ CEP 24020-141, Brazil
| | - Rodrigo B de Oliveira
- INMETRO, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Senhora das Graças, 50, Xerém, Duque de Caxias, CEP: 25250-020, RJ, Brazil; Departamento de Polícia Federal, Instituto Nacional de Criminalística, SAIS Quadra 07 Lote 23, Setor Policial Sul, CEP 70610-902, DF, Brazil
| | - Marcelo Corrêa Bernardes
- Programa de Pós-Graduação em Química, Instituto de Química (PPGQ), Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Valonguinho, Centro, Niterói, RJ CEP 24020-141, Brazil; Programa de Pós-Graduação em Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ CEP 24020-141, Brazil
| | - Annibal Duarte Pereira Netto
- Programa de Pós-Graduação em Química, Instituto de Química (PPGQ), Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Valonguinho, Centro, Niterói, RJ CEP 24020-141, Brazil; Programa de Pós-Graduação em Alimentos e Nutrição (PPGAN), Universidade Federal do Estado do Rio de Janeiro, Avenida Pasteur, 296, Rio de Janeiro, RJ CEP 22290-240, Brazil.
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Blessing M, Baran N. A review on environmental isotope analysis of aquatic micropollutants: Recent advances, pitfalls and perspectives. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Wu L, Suchana S, Flick R, Kümmel S, Richnow H, Passeport E. Carbon, hydrogen and nitrogen stable isotope fractionation allow characterizing the reaction mechanisms of 1H-benzotriazole aqueous phototransformation. WATER RESEARCH 2021; 203:117519. [PMID: 34391022 DOI: 10.1016/j.watres.2021.117519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/13/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
1H-benzotriazole is part of a larger family of benzotriazoles, which are widely used as lubricants, polymer stabilizers, corrosion inhibitors, and anti-icing fluid components. It is frequently detected in urban runoff, wastewater, and receiving aquatic environments. 1H-benzotriazole is typically resistant to biodegradation and hydrolysis, but can be transformed via direct photolysis and photoinduced mechanisms. In this study, the phototransformation mechanisms of 1H-benzotriazole were characterized using multi-element compound-specific isotope analysis (CSIA). The kinetics, transformation products, and isotope fractionation results altogether revealed that 1H-benzotriazole direct photolysis and indirect photolysis induced by OH radicals involved two alternative pathways. In indirect photolysis, aromatic hydroxylation dominated and was associated with small carbon (εC = -0.65 ± 0.03‰), moderate hydrogen (εH = -21.6‰), and negligible nitrogen isotope enrichment factors and led to hydroxylated forms of benzotriazole. In direct photolysis of 1H-benzotriazole, significant nitrogen (εN = -8.4 ± 0.4 to -4.2 ± 0.3‰) and carbon (εC = -4.3 ± 0.2 to -1.64 ± 0.04‰) isotope enrichment factors indicated an initial N-N bond cleavage followed by nitrogen elimination with a C-N bond cleavage. The results of this study highlight the potential for multi-element CSIA application to track 1H-benzotriazole degradation in aquatic environments.
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Affiliation(s)
- Langping Wu
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada
| | - Shamsunnahar Suchana
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada
| | - Robert Flick
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada
| | - Steffen Kümmel
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Hans Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Elodie Passeport
- Department of Civil and Mineral Engineering, University of Toronto, 35 St. George St., Toronto, ON M5S 1A4, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S 3E5, Canada.
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Liu Y, Guo Y, Wu W, Xiong Y, Sun C, Yuan L, Li M. A Machine Learning-Based QSAR Model for Benzimidazole Derivatives as Corrosion Inhibitors by Incorporating Comprehensive Feature Selection. Interdiscip Sci 2019; 11:738-747. [PMID: 31486019 DOI: 10.1007/s12539-019-00346-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 01/28/2023]
Abstract
BACKGROUND Computational prediction of inhibition efficiency (IE) for inhibitor molecules is a crucial supplementary way to design novel molecules that can efficiently inhibit corrosion onto metallic surfaces. PURPOSE Here we are dedicated to developing a new machine learning-based predictor for the inhibition efficiency (IE) of benzimidazole derivatives. METHODS First, a comprehensively numerical representation was given on inhibitor molecules from all aspects of energy, electronic, topological, physicochemical and spatial properties based on 3-D structures and 150 valid structural descriptors were obtained. Then, a thorough investigation of these structural descriptors was implemented. The multicollinearity-based clustering analysis was performed to remove the linear correlated feature variables, so 47 feature clusters were produced. Meanwhile, Gini importance by random forest (RF) was used to further measure the contributions of the descriptors in each cluster and 47 non-linear descriptors were selected with the highest Gini importance score in the corresponding cluster. Further, considering the limited number of available inhibitors, different feature subsets were constructed according to the Gini importance score ranking list of 47 descriptors. RESULTS Finally, support vector machine (SVM) models based on different feature subsets were tested by leave-one-out cross validation. Through comparisons, the optimal SVM model with the top 11 descriptors was achieved based on Poly kernel. This model yields a promising performance with the correlation coefficient (R) and root-mean-square error (RMSE) of 0.9589 and 4.45, respectively, which indicates that the method proposed by us gives the best performance for the current data. CONCLUSION Based on our model, 6 new benzimidazole molecules were designed and their IE values predicted by this model indicate that two of them have high potential as outstanding corrosion inhibitors.
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Affiliation(s)
- Youquan Liu
- Research Institute of Natural Gas Technology, Petro China Southwest Oil and Gas Field Company, Chengdu, 610213, China.
| | - Yanzhi Guo
- College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, People's Republic of China.
| | - Wengang Wu
- Research Institute of Natural Gas Technology, Petro China Southwest Oil and Gas Field Company, Chengdu, 610213, China
| | - Ying Xiong
- Research Institute of Natural Gas Technology, Petro China Southwest Oil and Gas Field Company, Chengdu, 610213, China
| | - Chuan Sun
- Research Institute of Natural Gas Technology, Petro China Southwest Oil and Gas Field Company, Chengdu, 610213, China
| | - Li Yuan
- Research Institute of Natural Gas Technology, Petro China Southwest Oil and Gas Field Company, Chengdu, 610213, China
| | - Menglong Li
- College of Chemistry, Sichuan University, Chengdu, Sichuan, 610064, People's Republic of China
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Torrentó C, Bakkour R, Glauser G, Melsbach A, Ponsin V, Hofstetter TB, Elsner M, Hunkeler D. Solid-phase extraction method for stable isotope analysis of pesticides from large volume environmental water samples. Analyst 2019; 144:2898-2908. [PMID: 30896686 DOI: 10.1039/c9an00160c] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Compound-specific isotope analysis (CSIA) is a valuable tool for assessing the fate of organic pollutants in the environment. However, the requirement of sufficient analyte mass for precise isotope ratio mass spectrometry combined with prevailing low environmental concentrations currently limits comprehensive applications to many micropollutants. Here, we evaluate the upscaling of solid-phase extraction (SPE) approaches for routine CSIA of herbicides. To cover a wide range of polarity, a SPE method with two sorbents (a hydrophobic hypercrosslinked sorbent and a hydrophilic sorbent) was developed. Extraction conditions, including the nature and volume of the elution solvent, the amount of sorbent and the solution pH, were optimized. Extractions of up to 10 L of agricultural drainage water (corresponding to up to 200 000-fold pre-concentration) were successfully performed for precise and sensitive carbon and nitrogen CSIA of the target herbicides atrazine, acetochlor, metolachlor and chloridazon, and metabolites desethylatrazine, desphenylchloridazon and 2,6-dichlorobenzamide in the sub-μg L-1-range. 13C/12C and 15N/14N ratios were measured by gas chromatography-isotope ratio mass spectrometry (GC/IRMS), except for desphenylchloridazon, for which liquid chromatography (LC/IRMS) and derivatization-GC/IRMS were used, respectively. The method validated in this study is an important step towards analyzing isotope ratios of pesticide mixtures in aquatic systems and holds great potential for multi-element CSIA applications to trace pesticide degradation in complex environments.
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Affiliation(s)
- Clara Torrentó
- Centre for Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland.
| | - Rani Bakkour
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry (NPAC), University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Aileen Melsbach
- Helmholtz Zentrum München, Institute of Groundwater Ecology, 85764 Neuherberg, Germany
| | - Violaine Ponsin
- Centre for Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland.
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Martin Elsner
- Helmholtz Zentrum München, Institute of Groundwater Ecology, 85764 Neuherberg, Germany and Technical University of Munich, Chair of Analytical Chemistry and Water Chemistry, 81377 Munich, Germany
| | - Daniel Hunkeler
- Centre for Hydrogeology and Geothermics (CHYN), University of Neuchâtel, 2000 Neuchâtel, Switzerland.
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Berens MJ, Ulrich BA, Strehlau JH, Hofstetter TB, Arnold WA. Mineral identity, natural organic matter, and repeated contaminant exposures do not affect the carbon and nitrogen isotope fractionation of 2,4-dinitroanisole during abiotic reduction. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:51-62. [PMID: 30484795 DOI: 10.1039/c8em00381e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The recent development of insensitive munitions, such as 2,4-dinitroanisole (DNAN), as components of military explosives has generated concern for potential subsurface contamination and created a need to fully characterize their transformation processes. Compound specific isotope analysis (CSIA) has proven to be a useful means of assessing transformation pathways according to characteristic stable isotope fractionation patterns. The C and N isotope fractionation of DNAN associated with abiotic and enzymatic hydrolysis was recently assessed. The extent to which DNAN isotope fractionation will be affected by other potentially competing transformation pathways known for nitroaromatic compounds (e.g., reduction) and if previous knowledge can be extrapolated to other environmental matrices remains to be understood. Here, we investigated the C and N isotope fractionation and reaction rate constants of DNAN during abiotic reduction mediated by mineral-associated Fe(ii) species as a function of mineral type, natural organic matter presence, and repeated exposures to DNAN. Though rate constants varied, N and C apparent kinetic isotope effects (AKIEs) remained consistent across all experiments (averaged values of 15N-AKIE = 1.0317 ± 0.0064 and 13C-AKIE = 1.0008 ± 0.0005) and revealed significant 15N- and minimal 13C-enrichment in agreement with previous work on nitroaromatic compounds. Moreover, the observed fractionation was clearly distinct from trends for abiotic and enzymatic hydrolysis. This study provides a strengthened basis for the use of CSIA as a robust tool for monitoring DNAN degradation in complex environmental matrices as a component of future remediation efforts.
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Affiliation(s)
- Matthew J Berens
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, MN 55455-0116, USA.
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Kraševec I, Prosen H. Solid-Phase Extraction of Polar Benzotriazoles as Environmental Pollutants: A Review. Molecules 2018; 23:molecules23102501. [PMID: 30274289 PMCID: PMC6222494 DOI: 10.3390/molecules23102501] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/04/2022] Open
Abstract
Polar benzotriazoles are corrosion inhibitors with widespread use; they are environmentally characterized as emerging pollutants in the water system, where they are present in low concentrations. Various extraction methods have been used for their separation from various matrices, ranging from classical liquid–liquid extractions to various microextraction techniques, but the most frequently applied extraction technique remains the solid-phase extraction (SPE), which is the focus of this review. We present an overview of the methods, developed in the last decade, applied for the determination of benzotriazoles in aqueous and solid environmental samples. Several other matrices, such as human urine and plant material, are also considered in the text. The methods are reviewed according to the determined compounds, sample matrices, cartridges and eluents used, extraction recoveries and the achieved limits of quantification. A critical evaluation of the advantages and drawbacks of the published methods is given.
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Affiliation(s)
- Ida Kraševec
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
| | - Helena Prosen
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
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Bakkour R, Bolotin J, Sellergren B, Hofstetter TB. Molecularly Imprinted Polymers for Compound-Specific Isotope Analysis of Polar Organic Micropollutants in Aquatic Environments. Anal Chem 2018; 90:7292-7301. [DOI: 10.1021/acs.analchem.8b00493] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Rani Bakkour
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Jakov Bolotin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Börje Sellergren
- Department of Biomedical Sciences, Malmö University, 20506 Malmö, Sweden
| | - Thomas B. Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
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Pati SG, Kohler HPE, Hofstetter TB. Characterization of Substrate, Cosubstrate, and Product Isotope Effects Associated With Enzymatic Oxygenations of Organic Compounds Based on Compound-Specific Isotope Analysis. Methods Enzymol 2017; 596:291-329. [PMID: 28911775 DOI: 10.1016/bs.mie.2017.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Enzymatic oxygenations are among the most important biodegradation and detoxification reactions of organic pollutants. In the environment, however, such natural attenuation processes are extremely difficult to monitor. Changes of stable isotope ratios of aromatic pollutants at natural isotopic abundances serve as proxies for isotope effects associated with oxygenation reactions. Such isotope fractionations offer new avenues for revealing the pathway and extent of pollutant transformation and provide new insights into the mechanisms of catalysis by Rieske non-heme ferrous iron oxygenases. Based on compound-specific C, H, N, and O isotope analysis, we present a comprehensive methodology with which isotope effects can be derived from the isotope fractionation measured in substrates, the cosubstrate O2, and organic oxygenation products. We use dioxygenation of nitrobenzene and 2-nitrotoluene by nitrobenzene dioxygenase as illustrative examples to introduce different mathematical procedures for deriving apparent substrate and product isotope effects. We present two experimental approaches to control reactant and product turnover for isotope fractionation analysis in experimental systems containing purified enzymes, E. coli clones, and pure strains of environmental microorganisms. Finally, we present instrumental procedures and sample treatment instructions for analysis of C, H, and N isotope analysis in organic compounds and O isotope analysis in aqueous O2 by gas and liquid chromatography coupled to isotope ratio mass spectrometry.
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Affiliation(s)
- Sarah G Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, Zürich, Switzerland
| | - Hans-Peter E Kohler
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, Zürich, Switzerland.
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Wijker RS, Zeyer J, Hofstetter TB. Isotope fractionation associated with the simultaneous biodegradation of multiple nitrophenol isomers by Pseudomonas putida B2. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:775-784. [PMID: 28470308 DOI: 10.1039/c6em00668j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Quantifying the extent of biodegradation of nitroaromatic compounds (NACs) in contaminated soils and sediments is challenging because of competing oxidative and reductive reaction pathways. We have previously shown that the stable isotope fractionation of NACs reveals the routes of degradation even if it is simultaneously caused by different bacteria. However, it is unclear whether compound-specific isotope analysis (CSIA) can be applied in situations where multiple pollutants are biodegraded by only one microorganism under multi-substrate conditions. Here we examined the C and N isotope fractionation of 2-nitrophenol (2-NP) and 3-nitrophenol (3-NP) during biodegradation by Pseudomonas putida B2 through monooxygenation and partial reductive pathways, respectively, in the presence of single substrates vs. binary substrate mixtures. Laboratory experiments showed that the reduction of 3-NP by Pseudomonas putida B2 is associated with large N and minor C isotope fractionation with C and N isotope enrichment factors, εC and εN, of -0.3 ± 0.1‰ and -22 ± 0.2‰, respectively. The opposite isotope fractionation trends were found for 2-NP monooxygenation. In the simultaneous presence of 2-NP and 3-NP, 2-NP is biodegraded at identical rate constants and εC and εN values (-1.0 ± 0.1‰ and -1.3 ± 0.2‰) to those found for the monooxygenation of 2-NP in single substrate experiments. While the pathway and N isotope fractionation of 3-NP reduction (εN = -24 ± 1.1‰) are independent of the presence of 2-NP, intermediates of 2-NP monooxygenation interfere with 3-NP reduction. Because neither pH, substrate uptake, nor aromatic substituents affected the kinetic isotope effects of nitrophenol biodegradation, our study illustrates that CSIA provides robust scientific evidence for the assessment of natural attenuation processes.
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Affiliation(s)
- Reto S Wijker
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, Zürich, Switzerland.
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Yarnes CT, Herszage J. The relative influence of derivatization and normalization procedures on the compound-specific stable isotope analysis of nitrogen in amino acids. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:693-704. [PMID: 28168754 DOI: 10.1002/rcm.7832] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 06/06/2023]
Abstract
RATIONALE Within the last decade, applications of compound-specific stable isotope analysis of nitrogen (δ15 N values) in amino acids (CSIA-AA) have developed rapidly, particularly within organismal ecology. Unlike with bulk stable isotope analysis (BSIA), the reproducibility of δ15 N-AA measurements has not been critically assessed. Two primary concerns include the diversity of techniques available for the derivatization of amino acids prior to analysis by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and the myriad of standardization practices and quality assurance procedures used across studies. METHODS We examined the relative effect of three normalization procedures, (1) internal reference calibration, (2) compound-specific calibration, and (3) scale-normalization, on the accuracy and precision of δ15 N-AA measurements by GC/C/IRMS and the comparability of δ15 N-AA measurements by two derivatization techniques, methoxycarbonylation-esterification and acetylation-esterification, across a range of organisms. RESULTS The overall accuracy and precision of δ15 N-AA measurements were improved following both compound-specific calibration and scale-normalization, as was the comparability of δ15 N-AA measurements of individual amino acids between derivatization techniques across organisms. The mean difference of scale-normalized δ15 N-AA values across all organisms between the two derivatization techniques was 0.19‰, much less than the typical analytical error associated with δ15 N-AA measurements (±1‰). CONCLUSIONS: Adoption of standardized calibration procedures will be important to establishing reproducibility in δ15 N-AA measurements, particularly across derivatization techniques. It is both technically practical and desirable for users of CSIA-AA to adopt practices in quality control and assessment similar to those outlined for BSIA, including the compound-specific calibration of δ15 N-AA values, followed by scale-normalization. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Christopher T Yarnes
- Stable Isotope Facility, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Julian Herszage
- Stable Isotope Facility, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
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Maier MP, Prasse C, Pati SG, Nitsche S, Li Z, Radke M, Meyer A, Hofstetter TB, Ternes TA, Elsner M. Exploring Trends of C and N Isotope Fractionation to Trace Transformation Reactions of Diclofenac in Natural and Engineered Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10933-10942. [PMID: 27635778 DOI: 10.1021/acs.est.6b02104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Although diclofenac ranks among the most frequently detected pharmaceuticals in the urban water cycle, its environmental transformation reactions remain imperfectly understood. Biodegradation-induced changes in 15N/14N ratios (εN = -7.1‰ ± 0.4‰) have indicated that compound-specific isotope analysis (CSIA) may detect diclofenac degradation. This singular observation warrants exploration for further transformation reactions. The present study surveys carbon and nitrogen isotope fractionation in other environmental and engineered transformation reactions of diclofenac. While carbon isotope fractionation was generally small, observed nitrogen isotope fractionation in degradation by MnO2 (εN = -7.3‰ ± 0.3‰), photolysis (εN = +1.9‰ ± 0.1‰), and ozonation (εN = +1.5‰ ± 0.2‰) revealed distinct trends for different oxidative transformation reactions. The small, secondary isotope effect associated with ozonation suggests an attack of O3 in a molecular position distant from the N atom. Model reactants for outer-sphere single electron transfer generated large inverse nitrogen isotope fractionation (εN = +5.7‰ ± 0.3‰), ruling out this mechanism for biodegradation and transformation by MnO2. In a river model, isotope fractionation-derived degradation estimates agreed well with concentration mass balances, providing a proof-of-principle validation for assessing micropollutant degradation in river sediment. Our study highlights the prospect of combining CSIA with transformation product analysis for a better assessment of transformation reactions within the environmental life of diclofenac.
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Affiliation(s)
- Michael P Maier
- Helmholtz Zentrum Muenchen, German Research Center, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg D-85764, Germany
| | - Carsten Prasse
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
- Department of Civil & Environmental Engineering, University of California , Berkeley, California, 94720 United States
| | - Sarah G Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , 8092 Zürich, Switzerland
| | - Sebastian Nitsche
- Helmholtz Zentrum Muenchen, German Research Center, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg D-85764, Germany
| | - Zhe Li
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University , 10691 Stockholm, Sweden
| | - Michael Radke
- Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University , 10691 Stockholm, Sweden
| | - Armin Meyer
- Helmholtz Zentrum Muenchen, German Research Center, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg D-85764, Germany
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , 8092 Zürich, Switzerland
| | - Thomas A Ternes
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Martin Elsner
- Helmholtz Zentrum Muenchen, German Research Center, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, Neuherberg D-85764, Germany
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14
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Pati SG, Kohler HPE, Pabis A, Paneth P, Parales RE, Hofstetter TB. Substrate and Enzyme Specificity of the Kinetic Isotope Effects Associated with the Dioxygenation of Nitroaromatic Contaminants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6708-16. [PMID: 26895026 DOI: 10.1021/acs.est.5b05084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Compound-specific isotope analysis (CSIA) is a promising approach for tracking biotransformation of organic pollutants, but isotope fractionation associated with aromatic oxygenations is only poorly understood. We investigated the dioxygenation of a series of nitroaromatic compounds to the corresponding catechols by two enzymes, namely, nitrobenzene and 2-nitrotoluene dioxygenase (NBDO and 2NTDO) to elucidate the enzyme- and substrate-specificity of C and H isotope fractionation. While the apparent (13)C- and (2)H-kinetic isotope effects of nitrobenzene, nitrotoluene isomers, 2,6-dinitrotoluene, and naphthalene dioxygenation by NBDO varied considerably, the correlation of C and H isotope fractionation revealed a common mechanism for nitrobenzene and nitrotoluenes. Similar observations were made for the dioxygenation of these substrates by 2NTDO. Evaluation of reaction kinetics, isotope effects, and commitment-to-catalysis based on experiment and theory showed that rates of dioxygenation are determined by the enzymatic O2 activation and aromatic C oxygenation. The contribution of enzymatic O2 activation to the reaction rate varies for different nitroaromatic substrates of NBDO and 2NTDO. Because aromatic dioxygenation by nonheme iron dioxygenases is frequently the initial step of biodegradation, O2 activation kinetics may also have been responsible for the minor isotope fractionation reported for the oxygenation of other aromatic contaminants.
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Affiliation(s)
- Sarah G Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , 8092 Zürich, Switzerland
| | - Hans-Peter E Kohler
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Anna Pabis
- Institute of Applied Radiation Chemistry, Lodz University of Technology , 90-924 Lodz, Poland
| | - Piotr Paneth
- Institute of Applied Radiation Chemistry, Lodz University of Technology , 90-924 Lodz, Poland
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, University of California , Davis, California 95616, United States
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , 8092 Zürich, Switzerland
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15
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Elsner M, Imfeld G. Compound-specific isotope analysis (CSIA) of micropollutants in the environment - current developments and future challenges. Curr Opin Biotechnol 2016; 41:60-72. [PMID: 27340797 DOI: 10.1016/j.copbio.2016.04.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/14/2016] [Accepted: 04/12/2016] [Indexed: 10/21/2022]
Abstract
Over the last decade, the occurrence of micropollutants in the environment has become a worldwide issue of increasing concern. Compound-specific stable-isotope analysis (CSIA) of natural isotopic abundance may greatly enhance the evaluation of sources and transformation processes of micropollutants, such as pesticides, personal care products or pharmaceuticals. We summarize recent advances from laboratory studies, review current limitations and analytical challenges associated with low concentrations and high polarity of micropollutants, and delineate the potential of micropolluant CSIA for field applications. We highlight future challenges and prospects regarding source apportionment, identification of biotic and abiotic transformation reactions on a mechanistic level, as well as integrative evaluation of degradation hot spots on the catchment scale. Such advances may feed into a framework for risk assessment of micropollutants that includes CSIA.
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Affiliation(s)
- Martin Elsner
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
| | - Gwenaël Imfeld
- Laboratoire d'Hydrologie et de Géochimie de Strasbourg (LHyGeS), UMR 7517, Université de Strasbourg/EOST, CNRS, 1 rue Blessig, 67084 Strasbourg Cedex, France
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16
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Schürner HKV, Maier MP, Eckert D, Brejcha R, Neumann CC, Stumpp C, Cirpka OA, Elsner M. Compound-Specific Stable Isotope Fractionation of Pesticides and Pharmaceuticals in a Mesoscale Aquifer Model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5729-39. [PMID: 27100740 DOI: 10.1021/acs.est.5b03828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Compound-specific isotope analysis (CSIA) receives increasing interest for its ability to detect natural degradation of pesticides and pharmaceuticals. Despite recent laboratory studies, CSIA investigations of such micropollutants in the environment are still rare. To explore the certainty of information obtainable by CSIA in a near-environmental setting, a pulse of the pesticide bentazone, the pesticide metabolite 2,6-dichlorobenzamide (BAM), and the pharmaceuticals diclofenac and ibuprofen was released into a mesoscale aquifer with quasi-two-dimensional flow. Concentration breakthrough curves (BTC) of BAM and ibuprofen demonstrated neither degradation nor sorption. Bentazone was transformed but did not sorb significantly, whereas diclofenac showed both degradation and sorption. Carbon and nitrogen CSIA could be accomplished in similar concentrations as for "traditional" priority pollutants (low μg/L range), however, at the cost of uncertainties (0.4-0.5‰ (carbon), 1‰ (nitrogen)). Nonetheless, invariant carbon and nitrogen isotope values confirmed that BAM was neither degraded nor sorbed, while significant enrichment of (13)C and in particular (15)N corroborated transformation of diclofenac and bentazone. Retardation of diclofenac was reflected in additional (15)N sorption isotope effects, whereas isotope fractionation of transverse dispersion could not be identified. These results provide a benchmark on the performance of CSIA to monitor the reactivity of micropollutants in aquifers and may guide future efforts to accomplish CSIA at even lower concentrations (ng/L range).
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Affiliation(s)
- Heide K V Schürner
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Michael P Maier
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Dominik Eckert
- Center for Applied Geosciences, University of Tübingen , Hölderlinstraße 12, 72074 Tübingen, Germany
| | - Ramona Brejcha
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Claudia-Constanze Neumann
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Christine Stumpp
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Olaf A Cirpka
- Center for Applied Geosciences, University of Tübingen , Hölderlinstraße 12, 72074 Tübingen, Germany
| | - Martin Elsner
- Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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17
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Prasse C, Stalter D, Schulte-Oehlmann U, Oehlmann J, Ternes TA. Spoilt for choice: A critical review on the chemical and biological assessment of current wastewater treatment technologies. WATER RESEARCH 2015; 87:237-70. [PMID: 26431616 DOI: 10.1016/j.watres.2015.09.023] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/02/2015] [Accepted: 09/11/2015] [Indexed: 05/28/2023]
Abstract
The knowledge we have gained in recent years on the presence and effects of compounds discharged by wastewater treatment plants (WWTPs) brings us to a point where we must question the appropriateness of current water quality evaluation methodologies. An increasing number of anthropogenic chemicals is detected in treated wastewater and there is increasing evidence of adverse environmental effects related to WWTP discharges. It has thus become clear that new strategies are needed to assess overall quality of conventional and advanced treated wastewaters. There is an urgent need for multidisciplinary approaches combining expertise from engineering, analytical and environmental chemistry, (eco)toxicology, and microbiology. This review summarizes the current approaches used to assess treated wastewater quality from the chemical and ecotoxicological perspective. Discussed chemical approaches include target, non-target and suspect analysis, sum parameters, identification and monitoring of transformation products, computational modeling as well as effect directed analysis and toxicity identification evaluation. The discussed ecotoxicological methodologies encompass in vitro testing (cytotoxicity, genotoxicity, mutagenicity, endocrine disruption, adaptive stress response activation, toxicogenomics) and in vivo tests (single and multi species, biomonitoring). We critically discuss the benefits and limitations of the different methodologies reviewed. Additionally, we provide an overview of the current state of research regarding the chemical and ecotoxicological evaluation of conventional as well as the most widely used advanced wastewater treatment technologies, i.e., ozonation, advanced oxidation processes, chlorination, activated carbon, and membrane filtration. In particular, possible directions for future research activities in this area are provided.
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Affiliation(s)
- Carsten Prasse
- Federal Institute of Hydrology (BfG), Department of Aquatic Chemistry, Koblenz, Germany; Department of Civil & Environmental Engineering, University of California at Berkeley, Berkeley, United States.
| | - Daniel Stalter
- National Research Centre for Environmental Toxicology, The University of Queensland, Queensland, Australia; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
| | | | - Jörg Oehlmann
- Goethe University Frankfurt, Department Aquatic Ecotoxicology, Frankfurt, Germany
| | - Thomas A Ternes
- Federal Institute of Hydrology (BfG), Department of Aquatic Chemistry, Koblenz, Germany
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18
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Ratti M, Canonica S, McNeill K, Bolotin J, Hofstetter TB. Isotope Fractionation Associated with the Indirect Photolysis of Substituted Anilines in Aqueous Solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12766-12773. [PMID: 26418612 DOI: 10.1021/acs.est.5b03119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Organic micropollutants containing aniline substructures are susceptible to different light-induced transformation processes in aquatic environments and water treatment operations. Here, we investigated the magnitude and variability of C and N isotope fractionation during the indirect phototransformation of four para-substituted anilines in aerated aqueous solutions. The model photosensitizers, namely 9,10-anthraquinone-1,5-disulfonate and methylene blue, were used as surrogates for dissolved organic matter chromophores generating excited triplet states in sunlit surface waters. The transformation of aniline, 4-CH3-, 4-OCH3-, and 4-Cl-aniline by excited triplet states of the photosensitizers was associated with inverse and normal N isotope fractionation, whereas C isotope fractionation was negligible. The apparent 15N kinetic isotope effects (AKIE) were almost identical for both photosensitizers, increased from 0.9958±0.0013 for 4-OCH3-aniline to 1.0035±0.0006 for 4-Cl-aniline, and correlated well with the electron donating properties of the substituent. N isotope fractionation is pH-dependent in that H+ exchange reactions dominate below and N atom oxidation processes above the pKa value of the substituted aniline's conjugate acid. Correlations of C and N isotope fractionation for indirect phototransformation were different from those determined previously for the direct photolysis of chloroanilines and offer new opportunities to distinguish between abiotic degradation pathways.
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Affiliation(s)
- Marco Ratti
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , CH-8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , CH-8092 Zürich, Switzerland
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , CH-8600 Dübendorf, Switzerland
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , CH-8092 Zürich, Switzerland
| | - Jakov Bolotin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , CH-8600 Dübendorf, Switzerland
| | - Thomas B Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , CH-8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich , CH-8092 Zürich, Switzerland
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19
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Ratti M, Canonica S, McNeill K, Erickson PR, Bolotin J, Hofstetter TB. Isotope fractionation associated with the direct photolysis of 4-chloroaniline. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4263-4273. [PMID: 25719866 DOI: 10.1021/es505784a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Compound-specific isotope analysis is a useful approach to track transformations of many organic soil and water pollutants. Applications of CSIA to characterize photochemical processes, however, have hardly been explored. In this work, we systematically studied C and N isotope fractionation associated with the direct photolysis of 4-Cl-aniline used as a model compound for organic micropollutants that are known to degrade via photochemical processes. Laboratory experiments were carried out at an irradiation wavelength of 254 nm over the pH range 2.0 to 9.0 as well as in the presence of Cs(+) as a quencher of excited singlet 4-Cl-aniline at pH 7.0 and 9.0. We observed considerable variation of C and N isotope enrichment factors, ϵC and ϵN, between -1.2 ± 0.2‰ to -2.7 ± 0.2‰ for C and -0.6 ± 0.2‰ to -9.1 ± 1.6‰ for N, respectively, which could not be explained by the speciation of 4-Cl-aniline alone. In the presence of 1 M Cs(+), we found a marked increase of apparent (13)C-kinetic isotope effects ((13)C-AKIE) and decrease of 4-Cl-aniline fluorescence lifetimes. Our data suggest that variations of C and N isotope fractionation originate from heterolytic dechlorination of excited triplet and singlet states of 4-Cl-aniline. Linear correlations of (13)C-AKIE vs (15)N-AKIE were distinctly different for these two reaction pathways and may be explored further for the identification of photolytic aromatic dechlorination reactions.
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Affiliation(s)
- Marco Ratti
- †Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- ‡Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, CH-8092 Zürich, Switzerland
| | - Silvio Canonica
- †Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Kristopher McNeill
- ‡Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, CH-8092 Zürich, Switzerland
| | - Paul R Erickson
- ‡Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, CH-8092 Zürich, Switzerland
| | - Jakov Bolotin
- †Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Thomas B Hofstetter
- †Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- ‡Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, CH-8092 Zürich, Switzerland
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20
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Spahr S, Bolotin J, Schleucher J, Ehlers I, von Gunten U, Hofstetter TB. Compound-Specific Carbon, Nitrogen, and Hydrogen Isotope Analysis of N-Nitrosodimethylamine in Aqueous Solutions. Anal Chem 2015; 87:2916-24. [DOI: 10.1021/ac5044169] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephanie Spahr
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- School
of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jakov Bolotin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
| | - Jürgen Schleucher
- Umeå University, Department of Medical Biochemistry
and Biophysics, S-90187 Umeå, Sweden
| | - Ina Ehlers
- Umeå University, Department of Medical Biochemistry
and Biophysics, S-90187 Umeå, Sweden
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- School
of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Thomas B. Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
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21
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Herrero P, Borrull F, Pocurull E, Marcé RM. An overview of analytical methods and occurrence of benzotriazoles, benzothiazoles and benzenesulfonamides in the environment. Trends Analyt Chem 2014. [DOI: 10.1016/j.trac.2014.06.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Pati SG, Kohler HPE, Bolotin J, Parales RE, Hofstetter TB. Isotope effects of enzymatic dioxygenation of nitrobenzene and 2-nitrotoluene by nitrobenzene dioxygenase. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:10750-10759. [PMID: 25101486 DOI: 10.1021/es5028844] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Oxygenation of aromatic rings is a frequent initial step in the biodegradation of persistent contaminants, and the accompanying isotope fractionation is increasingly used to assess the extent of transformation in the environment. Here, we systematically investigated the dioxygenation of two nitroaromatic compounds (nitrobenzene and 2-nitrotoluene) by nitrobenzene dioxygenase (NBDO) to obtain insights into the factors governing its C, H, and N isotope fractionation. Experiments were carried out at different levels of biological complexity from whole bacterial cells to pure enzyme. C, H, and N isotope enrichment factors and kinetic isotope effects (KIEs) were derived from the compound-specific isotope analysis of nitroarenes, whereas C isotope fractionation was also quantified in the oxygenated reaction products. Dioxygenation of nitrobenzene to catechol and 2-nitrotoluene to 3-methylcatechol showed large C isotope enrichment factors, ϵC, of -4.1 ± 0.2‰ and -2.5 ± 0.2‰, respectively, and was observed consistently in the substrates and dioxygenation products. ϵH- and ϵN-values were smaller, that is -5.7 ± 1.3‰ and -1.0 ± 0.3‰, respectively. C isotope fractionation was also identical in experiments with whole bacterial cells and pure enzymes. The corresponding (13)C-KIEs for the dioxygenation of nitrobenzene and 2-nitrotoluene were 1.025 ± 0.001 and 1.018 ± 0.001 and suggest a moderate substrate specificity. Our study illustrates that dioxygenation of nitroaromatic contaminants exhibits a large C isotope fractionation, which is not masked by substrate transport and uptake processes and larger than dioxygenation of other aromatic hydrocarbons.
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Affiliation(s)
- Sarah G Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
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23
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Huntscha S, Hofstetter TB, Schymanski EL, Spahr S, Hollender J. Biotransformation of benzotriazoles: insights from transformation product identification and compound-specific isotope analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:4435-4443. [PMID: 24621328 DOI: 10.1021/es405694z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Benzotriazoles are widely used domestic and industrial corrosion inhibitors and have become omnipresent organic micropollutants in the aquatic environment. Here, the range of aerobic biological degradation mechanisms of benzotriazoles in activated sludge was investigated. Degradation pathways were elucidated by identifying transient and persistent transformation products in batch experiments using liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). In addition, initial reactions were studied using compound-specific isotope analysis (CSIA). Biodegradation half-lives of 1.0 days for 1H-benzotriazole, 8.5 days for 4-methyl-1H-benzotriazole, and 0.9 days for 5-methyl-1H-benzotriazole with activated sludge confirmed their known partial persistence in conventional wastewater treatment. Major transformation products were identified as 4- and 5-hydroxy-1H-benzotriazole for the degradation of 1H-benzotriazole, and 1H-benzotriazole-5-carboxylic acid for the degradation of 5-methyl-1H-benzotriazole. These transformation products were found in wastewater effluents, showing their environmental relevance. Many other candidate transformation products, tentatively identified by interpretation of HR-MS/MS spectra, showed the broad range of possible reaction pathways including oxidation, alkylation, hydroxylation and indicate the significance of cometabolic processes for micropollutant degradation in biological wastewater treatment in general. The combination of evidence from product analysis with the significant carbon and nitrogen isotope fractionation suggests that aromatic monohydroxylation is the predominant step during the biotransformation of 1H-benzotriazole.
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Affiliation(s)
- Sebastian Huntscha
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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Maier MP, De Corte S, Nitsche S, Spaett T, Boon N, Elsner M. C & N isotope analysis of diclofenac to distinguish oxidative and reductive transformation and to track commercial products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2312-20. [PMID: 24397428 DOI: 10.1021/es403214z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Although diclofenac is frequently found in aquatic systems, its degradability in the environment remains imperfectly understood. On the one hand, evidence from concentration analysis alone is inconclusive if an unknown hydrology impedes a distinction between degradation and dilution. On the other hand, not all transformation products may be detectable. As a new approach, we therefore developed GC-IRMS (gas chromatography-isotope-ratio mass-spectrometry) analysis for carbon and nitrogen isotope measurements of diclofenac. The method uses a derivatization step that can be conducted either online or offline, for optimized throughput or sensitivity, respectively. In combination with on-column injection, the latter method enables determination of diclofenac isotope ratios down to the sub-μgL(-1) range in environmental samples. Degradation in an aerobic sediment-water system showed strong nitrogen isotope fractionation (εN = -7.1‰), whereas reductive diclofenac dechlorination was associated with significant carbon isotope fractionation (εC = -2.0‰). Hence dual element isotope analysis bears potential not only to detect diclofenac degradation, but even to distinguish both transformation pathways in the environment. In an explorative survey, analysis of commercial diclofenac products showed significant differences in carbon and nitrogen isotope ratios, demonstrating a further potential to track, and potentially even to authenticate, commercial production batches.
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Affiliation(s)
- Michael P Maier
- Helmholtz Zentrum Muenchen, German Research Center, Institute of Groundwater Ecology , Ingolstädter Landstrasse 1, Neuherberg D-85764, Germany
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Wijker RS, Kurt Z, Spain JC, Bolotin J, Zeyer J, Hofstetter TB. Isotope fractionation associated with the biodegradation of 2- and 4-nitrophenols via monooxygenation pathways. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:14185-14193. [PMID: 24266668 DOI: 10.1021/es403876u] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Monooxygenation is an important route of nitroaromatic compound (NAC) biodegradation and it is widely found for cometabolic transformations of NACs and other aromatic pollutants. We investigated the C and N isotope fractionation of nitrophenol monooxygenation to complement the characterization of NAC (bio)degradation pathways by compound-specific isotope analysis (CSIA). Because of the large diversity of enzymes catalyzing monooxygenations, we studied the combined C and N isotope fractionation and the corresponding (13)C- and (15)N-apparent kinetic isotope effects (AKIEs) of four nitrophenol-biodegrading microorganisms (Bacillus spharericus JS905, Pseudomonas sp. 1A, Arthrobacter sp. JS443, Pseudomonas putida B2) in the pH range 6.1-8.6 with resting cells and crude cell extracts. While the extent of C and N isotope fractionation and the AKIE-values varied considerably for the different organisms, the correlated C and N isotope signatures (δ(15)N vs δ(13)C) revealed trends, indicative of two distinct monooxygenation pathways involving hydroxy-1,4-benzoquinone or 1,2- and 1,4-benzoquinone intermediates, respectively. The distinction was possible based on larger secondary (15)N-AKIEs associated with the benzoquinone pathway. Isotope fractionation was neither masked substantially by nitrophenol speciation nor transport across cell membranes. Only when 4-nitrophenol was biodegraded by Pseudomonas sp. 1A did isotope fractionation become negligible, presumably due to rate-limiting substrate binding steps pertinent to the catalytic cycle of flavin-dependent monooxygenases.
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Affiliation(s)
- Reto S Wijker
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , CH-8600 Dübendorf, Switzerland
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Wijker RS, Bolotin J, Nishino SF, Spain JC, Hofstetter TB. Using compound-specific isotope analysis to assess biodegradation of nitroaromatic explosives in the subsurface. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:6872-6883. [PMID: 23547531 DOI: 10.1021/es3051845] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Assessing the fate of nitroaromatic explosives in the subsurface is challenging because contaminants are present in different phases (e.g., bound to soil or sediment matrix or as solid-phase residues) and transformation takes place via several potentially competing pathways over time-scales of decades. We developed a procedure for compound-specific analysis of stable C, N, and H isotopes in nitroaromatic compounds (NACs) and characterized biodegradation of 2,4,6-trinitrotoluene (TNT) and two dinitrotoluene isomers (2,4-DNT and 2,6-DNT) in subsurface material of a contaminated site. The type and relative contribution of reductive and oxidative pathways to the degradation of the three contaminants was inferred from the combined evaluation of C, N, and H isotope fractionation. Indicative trends of Δδ(15)N vs Δδ(13)C and Δδ(2)H vs Δδ(13)C were obtained from laboratory model systems for biodegradation pathways initiated via (i) dioxygenation, (ii) reduction, and (iii) CH3-group oxidation. The combined evaluation of NAC isotope fractionation in subsurface materials and in laboratory experiments suggests that in the field, 86-89% of 2,4-DNT transformation was due to dioxygenation while TNT was mostly reduced and 2,6-DNT reacted via a combination of reduction and CH3-group oxidation. Based on historic information on site operation, our data imply biodegradation of 2,4-DNT with half-lives of up to 9-17 years compared to 18-34 years for cometabolic transformation of TNT and 2,6-DNT.
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Affiliation(s)
- Reto S Wijker
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
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Schreglmann K, Hoeche M, Steinbeiss S, Reinnicke S, Elsner M. Carbon and nitrogen isotope analysis of atrazine and desethylatrazine at sub-microgram per liter concentrations in groundwater. Anal Bioanal Chem 2012; 405:2857-67. [PMID: 23274558 DOI: 10.1007/s00216-012-6616-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 11/27/2022]
Abstract
Environmental degradation of organic micropollutants is difficult to monitor due to their diffuse and ubiquitous input. Current approaches-concentration measurements over time, or daughter-to-parent compound ratios-may fall short, because they do not consider dilution, compound-specific sorption characteristics or alternative degradation pathways. Compound-specific isotope analysis (CSIA) offers an alternative approach based on evidence from isotope values. Until now, however, the relatively high limits for precise isotope analysis by gas chromatography-isotope ratio mass spectrometry (GC-IRMS) have impeded CSIA of sub-microgram-per-liter scale micropollutant concentrations in field samples. This study presents the first measurements of C and N isotope ratios of the herbicide atrazine and its metabolite desethylatrazine at concentrations of 100 to 1,000 ng/L in natural groundwater samples. Solid-phase extraction and preparative HPLC were tested and validated for preconcentration and cleanup of groundwater samples of up to 10 L without bias by isotope effects. Matrix interferences after solid-phase extraction could be greatly reduced by a preparative HPLC cleanup step prior to GC-IRMS analysis. Sensitivity was increased by a factor of 6 to 8 by changing the injection method from large-volume to cold-on-column injection on the GC-IRMS system. Carbon and nitrogen isotope values of field samples showed no obvious correlation with concentrations or desethylatrazine-to-atrazine ratios. Contrary to expectations, however, δ (13) C values of desethylatrazine were consistently less negative than those of atrazine from the same sites. Potentially, this line of evidence may contain information about further desethylatrazine degradation. In such a case, the common practice of using desethylatrazine-to-atrazine ratios would underestimate natural atrazine degradation.
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Affiliation(s)
- Kathrin Schreglmann
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Groundwater Ecology, Neuherberg, Germany
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