R. Brix - Academia.edu (original) (raw)

Papers by R. Brix

Research paper thumbnail of Validation of sample pre-treatment, bioassay responses and identification methods for effect directed analysis (EDA)

Research paper thumbnail of Assessment and modelling of bioavailability and food web exposure in three European rivers: Scheldt, Elbe and Llobregat

Research paper thumbnail of Bioavailability and bioaccumulation as crucial factors linking contamination and ecological status

Research paper thumbnail of Liquid Chromatography/Mass Spectrometry Method for Determination of Perfluorooctane Sulfonyl Fluoride upon Derivatization with Benzylamine

Analytical Chemistry, 2011

Perfluorooctane sulfonyl fluoride (PFOSF) is a main precursor of environmentally ubiquitous perfl... more Perfluorooctane sulfonyl fluoride (PFOSF) is a main precursor of environmentally ubiquitous perfluorooctanesulfonate (PFOS), and the quantity released to the environment is substantial. Determination of PFOSF, particularly at low concentrations, presents significant challenges for high-performance liquid chromatography and liquid chromatography/mass spectrometry (LC/MS) analyses due to the lack of chromophore and ionizable functional group, respectively. In this study, a new method was developed by derivatizing PFOSF with benzylamine to allow rapid quantitative analysis by using LC/MS. The method demonstrated good linearity in the range from 2 to 80 ng mL(-1) with r(2) > 0.994 for the derivatization product while the absolute detection limit was 2.5 pg. Liquid-liquid and liquid-solid extraction procedures were established for analysis of water and soil samples, and recoveries were in the range of 51-128%. In addition, the derivatization was selective for PFOSF, whereas PFOS did not nearly react. The developed simple analytical method with good reproducibility might not only be applied for analysis of PFOSF in the environment but also be applicable for supporting investigations on environmental fate of PFOSF, particularly its environmental and biotransformation to PFOS.

Research paper thumbnail of Toxicological profiling of hot spots for effect directed analysis in the Elbe, Scheldt and Llobregat rivers

Research paper thumbnail of Strategies for identification of unknown compounds from EDA studies, using an Orbitrap high resolution mass spectrometer

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

Research paper thumbnail of Solubility of nonylphenol and nonylphenol ethoxylates. On the possible role of micelles

Research paper thumbnail of Dose-dependence of coumarin elimination and inhibitory effect of 8-methoxy-psoralen

Research paper thumbnail of Identification of disinfection by-products of selected triazines in drinking water by LC-Q-ToF-MS/MS and evaluation of their toxicity

Journal of Mass Spectrometry, 2009

During the development of an on-line solid phase extraction-liquid chromatography-ultraviolet det... more During the development of an on-line solid phase extraction-liquid chromatography-ultraviolet detection (SPE-LC-UV) analytical method for determination of eight selected triazines; ametryn, atrazine, cyanazine, metrybuzine, prometryn, propazin, simazine, and terbutryn, in drinking water, it was observed that the retention times of three of them (ametryn, prometryn, and terbutryn) in Milli-Q water were different from those in chlorinated Milli-Q water, indicating the formation of new products. The cause of this change was found in the oxidation of the molecules as a result of chlorination with sodium hypochlorite. Experiments performed at varying concentrations of triazines and hypochlorite showed that the extent of the reaction depended on their relative concentrations. At the maximum admissible level of 100 ng/l for individual pesticides in drinking water, no apparent transformation was observed in the absence or at low concentrations (0.05 mg/l) of hypochlorite; however, on increasing the concentration of hypochlorite to the level typically present in drinking water (0.9 mg/l) the transformation was complete. The reaction is quite fast; within 1 h the parent compound is completely degraded and after 22 h the concentrations of the by-products are constant. Investigation of the by-products by ultra performance liquid chromatography-quadrupole-time of flight- tandem mass spectrometry (UPLC-Q-ToF-MS/MS) has shown that all three triazines follow a similar transformation pathway, forming four new molecules whose structure have been elucidated. The acute toxicity of the new products was investigated using a standard method based on the bioluminescence inhibition of Vibrio fischeri, and the by-products showed a higher toxicity than that of the parent compounds.

Research paper thumbnail of Primary and complex stressors in polluted mediterranean rivers: Pesticide effects on biological communities

Journal of Hydrology, 2010

Research paper thumbnail of Comparative study of an estradiol enzyme-linked immunosorbent assay kit, liquid chromatography–tandem mass spectrometry, and ultra performance liquid chromatography–quadrupole time of flight mass spectrometry for part-per-trillion analysis of estrogens in water samples

Journal of Chromatography A, 2007

Research paper thumbnail of Bridging Levels of Pharmaceuticals in River Water with Biological Community Structure in the Llobregat River Basin (Northeast Spain)

Environmental Toxicology and Chemistry, 2009

Research paper thumbnail of Establishing potential links between the presence of alkylphenolic compounds and the benthic community in a European river basin

Environmental Science and Pollution Research, 2012

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

This paper presents a study evaluating the suitability of recombinant yeast-based estrogenicity a... more This paper presents a study evaluating the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool for monitoring of the chemical status of water bodies in support of the Water Framework Directive (WFD). Three different recombinant yeast-based assays were evaluated; the Yeast Estrogen Screen (YES), the Recombinant Yeast Assay (RYA) and the Rikilt Estrogen bioAssay (REA), of which the YES assay was employed by two different laboratories. No significant difference between the performance of neither the different laboratories, nor the different yeast-assays was observed. Six batches of eleven samples each were analysed one week apart by the four participating laboratories and the robustness, repeatability and reproducibility of the participating yeast-based assays were evaluated. The setup included a correlation between bioassay results and results from chemical target analysis, which gave valuable information in the evaluation of the assays' performance. A good agreement was found between chemical and bioassay results, showing that the yeast-based assays can give valuable information in WFD work. However, the low sensitivity of the assays towards alkylphenols needs to be significantly improved if they are to be used for monitoring of these compounds. The study further led to suggestions on ways to improve traceability and quality assurance of the yeast-based assays.

Research paper thumbnail of Environmental risk assessment of pharmaceuticals in rivers: Relationships between hazard indexes and aquatic macroinvertebrate diversity indexes in the Llobregat River (NE Spain)

Environment International, 2010

Research paper thumbnail of Toxicity assessment of sediments from three European river basins using a sediment contact test battery

Ecotoxicology and Environmental Safety, 2011

Research paper thumbnail of Characterizing field sediments from three European river basins with special emphasis on endocrine effects – A recommendation for Potamopyrgus antipodarum as test organism

Research paper thumbnail of Wastewater reuse in Mediterranean semi-arid areas: The impact of discharges of tertiary treated sewage on the load of polar micro pollutants in the Llobregat river (NE Spain)

Research paper thumbnail of Validation of sample pre-treatment, bioassay responses and identification methods for effect directed analysis (EDA)

Research paper thumbnail of Assessment and modelling of bioavailability and food web exposure in three European rivers: Scheldt, Elbe and Llobregat

Research paper thumbnail of Bioavailability and bioaccumulation as crucial factors linking contamination and ecological status

Research paper thumbnail of Liquid Chromatography/Mass Spectrometry Method for Determination of Perfluorooctane Sulfonyl Fluoride upon Derivatization with Benzylamine

Analytical Chemistry, 2011

Perfluorooctane sulfonyl fluoride (PFOSF) is a main precursor of environmentally ubiquitous perfl... more Perfluorooctane sulfonyl fluoride (PFOSF) is a main precursor of environmentally ubiquitous perfluorooctanesulfonate (PFOS), and the quantity released to the environment is substantial. Determination of PFOSF, particularly at low concentrations, presents significant challenges for high-performance liquid chromatography and liquid chromatography/mass spectrometry (LC/MS) analyses due to the lack of chromophore and ionizable functional group, respectively. In this study, a new method was developed by derivatizing PFOSF with benzylamine to allow rapid quantitative analysis by using LC/MS. The method demonstrated good linearity in the range from 2 to 80 ng mL(-1) with r(2) > 0.994 for the derivatization product while the absolute detection limit was 2.5 pg. Liquid-liquid and liquid-solid extraction procedures were established for analysis of water and soil samples, and recoveries were in the range of 51-128%. In addition, the derivatization was selective for PFOSF, whereas PFOS did not nearly react. The developed simple analytical method with good reproducibility might not only be applied for analysis of PFOSF in the environment but also be applicable for supporting investigations on environmental fate of PFOSF, particularly its environmental and biotransformation to PFOS.

Research paper thumbnail of Toxicological profiling of hot spots for effect directed analysis in the Elbe, Scheldt and Llobregat rivers

Research paper thumbnail of Strategies for identification of unknown compounds from EDA studies, using an Orbitrap high resolution mass spectrometer

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

Research paper thumbnail of Solubility of nonylphenol and nonylphenol ethoxylates. On the possible role of micelles

Research paper thumbnail of Dose-dependence of coumarin elimination and inhibitory effect of 8-methoxy-psoralen

Research paper thumbnail of Identification of disinfection by-products of selected triazines in drinking water by LC-Q-ToF-MS/MS and evaluation of their toxicity

Journal of Mass Spectrometry, 2009

During the development of an on-line solid phase extraction-liquid chromatography-ultraviolet det... more During the development of an on-line solid phase extraction-liquid chromatography-ultraviolet detection (SPE-LC-UV) analytical method for determination of eight selected triazines; ametryn, atrazine, cyanazine, metrybuzine, prometryn, propazin, simazine, and terbutryn, in drinking water, it was observed that the retention times of three of them (ametryn, prometryn, and terbutryn) in Milli-Q water were different from those in chlorinated Milli-Q water, indicating the formation of new products. The cause of this change was found in the oxidation of the molecules as a result of chlorination with sodium hypochlorite. Experiments performed at varying concentrations of triazines and hypochlorite showed that the extent of the reaction depended on their relative concentrations. At the maximum admissible level of 100 ng/l for individual pesticides in drinking water, no apparent transformation was observed in the absence or at low concentrations (0.05 mg/l) of hypochlorite; however, on increasing the concentration of hypochlorite to the level typically present in drinking water (0.9 mg/l) the transformation was complete. The reaction is quite fast; within 1 h the parent compound is completely degraded and after 22 h the concentrations of the by-products are constant. Investigation of the by-products by ultra performance liquid chromatography-quadrupole-time of flight- tandem mass spectrometry (UPLC-Q-ToF-MS/MS) has shown that all three triazines follow a similar transformation pathway, forming four new molecules whose structure have been elucidated. The acute toxicity of the new products was investigated using a standard method based on the bioluminescence inhibition of Vibrio fischeri, and the by-products showed a higher toxicity than that of the parent compounds.

Research paper thumbnail of Primary and complex stressors in polluted mediterranean rivers: Pesticide effects on biological communities

Journal of Hydrology, 2010

Research paper thumbnail of Comparative study of an estradiol enzyme-linked immunosorbent assay kit, liquid chromatography–tandem mass spectrometry, and ultra performance liquid chromatography–quadrupole time of flight mass spectrometry for part-per-trillion analysis of estrogens in water samples

Journal of Chromatography A, 2007

Research paper thumbnail of Bridging Levels of Pharmaceuticals in River Water with Biological Community Structure in the Llobregat River Basin (Northeast Spain)

Environmental Toxicology and Chemistry, 2009

Research paper thumbnail of Establishing potential links between the presence of alkylphenolic compounds and the benthic community in a European river basin

Environmental Science and Pollution Research, 2012

Research paper thumbnail of Evaluation of the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool in environmental samples

Environment International, 2010

This paper presents a study evaluating the suitability of recombinant yeast-based estrogenicity a... more This paper presents a study evaluating the suitability of recombinant yeast-based estrogenicity assays as a pre-screening tool for monitoring of the chemical status of water bodies in support of the Water Framework Directive (WFD). Three different recombinant yeast-based assays were evaluated; the Yeast Estrogen Screen (YES), the Recombinant Yeast Assay (RYA) and the Rikilt Estrogen bioAssay (REA), of which the YES assay was employed by two different laboratories. No significant difference between the performance of neither the different laboratories, nor the different yeast-assays was observed. Six batches of eleven samples each were analysed one week apart by the four participating laboratories and the robustness, repeatability and reproducibility of the participating yeast-based assays were evaluated. The setup included a correlation between bioassay results and results from chemical target analysis, which gave valuable information in the evaluation of the assays' performance. A good agreement was found between chemical and bioassay results, showing that the yeast-based assays can give valuable information in WFD work. However, the low sensitivity of the assays towards alkylphenols needs to be significantly improved if they are to be used for monitoring of these compounds. The study further led to suggestions on ways to improve traceability and quality assurance of the yeast-based assays.

Research paper thumbnail of Environmental risk assessment of pharmaceuticals in rivers: Relationships between hazard indexes and aquatic macroinvertebrate diversity indexes in the Llobregat River (NE Spain)

Environment International, 2010

Research paper thumbnail of Toxicity assessment of sediments from three European river basins using a sediment contact test battery

Ecotoxicology and Environmental Safety, 2011

Research paper thumbnail of Characterizing field sediments from three European river basins with special emphasis on endocrine effects – A recommendation for Potamopyrgus antipodarum as test organism

Research paper thumbnail of Wastewater reuse in Mediterranean semi-arid areas: The impact of discharges of tertiary treated sewage on the load of polar micro pollutants in the Llobregat river (NE Spain)