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A large number of pharmacologically active compounds have been detected in the aquatic environment during the last decade [1] and this gives rise to many concerns [2]. The substances have been disclosed by accident, clever search or elaborate mass spectrometry. Nowadays a broad spectrum of drug parent compounds can be screened for [3], yet the knowledge about the presence of isomers and transformation products (metabolites, conjugates, degradates) is still limited.
This study comprises the development of an enzyme-linked immunosorbent assay (ELISA) for the quantification of caffeine in complex aqueous matrices without any sample clean-up procedure. Salinity and dissolved organic matter were selected as potential interfering agents. The addition of a sample buffer containing bovine serum albumin (BSA) prior to the sample was found to decrease the influence of those interfering agents. The working range of the developed method was 0.1–100 µg L- 1. Quantification of caffeine was possible in 43 out of 51 real aqueous samples, at values between < LOD and 15 µg L- 1. Results correlate well with those obtained by LCMS/MS. To the best of our knowledge this is the first study dealing with the quantification of caffeine in Portugal's surface waters.
A frequently studied environmental contaminant is the active substance diclofenac, which is removed insufficiently in sewage treatment plants. Since its inclusion in the watch list of the EU Water Framework Directive, the concentrations in surface waters will be determined throughout Europe. For this, still, more precise analytical methods are needed. As a reference, HPLC-MS is frequently employed. One of the major metabolites is 4’-hydroxydiclofenac (4’-OH-DCF). Also, diclofenac lactam is important for assessing degradation and transformation. Aceclofenac (ACF), the glycolic acid ester of diclofenac is used as a drug, too, and could potentially be cleaved to yield diclofenac again. In various sewage treatment plant influent samples, diclofenac, 4’-OH-DCF, DCF lactam and ACF could be determined with detection limits of 3 µg/L, 0.2 µg/L, 0.17 µg/L and 10 ng/L, respectively.
The main goal of the study was to evaluate the catalytic activity of two hybrid nanocatalysts consisting in Fe3O4 nanoparticles modified with either chitosan (CS) or polyethylene glycol (PEG)/ferrous oxalate (FO), and further deposited on solid substrate as thin films. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were employed for the structural and morphological characterizations of the heterogeneous catalysts. The Degradation kinetic studies of two reactive azo dye (Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84)) as well as Bisphenol A (BPA) solutions were carried out using Fenton-like oxidation, in the presence of different concentrations of H2O2, at initial near-neutral pH and room temperature. The results indicated that a low amount of catalytic material (0.15 g/L), deposited as thin film, was able to efficiently trigger dye degradation in solution in the presence of 6.5mmol/LH2O2 for RB5 and of only 1.6mmol/LH2O2 in the case of BPA and RY84. In the presence of complex matrices such asWWTP waters, the removal of BPAwas low (only 24% for effluent samples). Our findings recommend the studied immobilized nanocatalysts as promising economical tools for the pretreatment of wastewaters using advanced oxidation processes (AOPs).
Singlet oxygen generation potential of two novel free-base-porphyrin photocatalysts was investigated. The freebase-porphyrin-sensitized Fe3O4 magnetic nanoparticles (MNPs) were tested for the degradation of the model pollutant Bisphenol A (BPA) in aqueous solution, for the first time. MNPs with either cubic or spherical shape were synthesized using the sonochemical approach, followed by sensitizing with photoactive 4,4′,4′′,4′′′- (Porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP). The resulted photocatalysts were characterized in detail by scanning and transmission electron microscopy, Brunauer–Emmett–Teller analysis, spectral techniques and vibrating sample magnetometry. The electron spin resonance experiments have confirmed the high activity of the photocatalysts through the efficient formation of singlet oxygen in solution. The optimum operational parameters for BPA degradation were established as follows: 1.0 μmol L−1 BPA, 1.0 g L−1 of photocatalyst, 100 μmol L−1 H2O2, under UVA irradiation. In these conditions, the results for both photocatalysts revealed that after only 10 min of reaction, over 64% and ca. 90% of BPA have been removed from solution in the absence and presence of H2O2, respectively. Whereas after 60 minutes of treatment, only 24% of BPA in real wastewater effluent samples were removed under UVA irradiation in the absence of H2O2, showing the high complexity of real wastewater. Moreover, both photocatalysts were successfully used for BPA removal in three consecutive runs, without significant loss of catalytic features.
Estrone (E1), a metabolite of the estrogenic hormones 17β-estradiol (β-E2) and 17α-estradiol (α-E2), is itself a potent estrogen which can have a significant impact on the hormonal balance. Due to ist high potential for adverse effects on human health and aquatic life even at pg/L to ng/L levels, its appearance in water should be monitored. E1 has also been considered a marker substance for the presence of other estrogens. This study presents a newly developed direct competitive enzymelinked immunosorbent assay (ELISA) for quantification of E1 in environmental water samples using new monoclonal antibodies.
The quantification range of the ELISA is 0.15 μg/L to 8.7 μg/L E1, and the limit of detection is around 60 ng/L for not pre-concentrated water samples. A pre-concentration step after careful selection of suitable phases for SPE was developed, too. The influence of organic solvents and natural organic matter on the ELISA was assessed. The high selectivity of the monoclonal antibody was demonstrated by determining the cross-reactivity against 20 structurally related compounds.
For the assessment of matrix effects, a concept (“LC–ELISA”) is thoroughly exploited, i.e., separating complex samples by HPLC into 0.3 min fractions and determination of the apparent E1 concentration. Furthermore, fractions with interferences for nontarget/suspected-target analysis can be assigned. A dilution approach was applied to distinguish between specific interferences (cross-reactants) and non-specific interferences (matrix effects). In the determination of 18 environmental samples, a good agreement of the E1 concentration in the respective fractions was obtained with mean recoveries of 103 % to 132 % comparing ELISA to LC–MS/MS.
Pharmacologically active compounds are often detected in wastewater and surface waters. The nonsteroidal anti-inflammatory drug diclofenac (DCF) was included in the European watch list of substances that requires its environmental monitoring in the member states. DCF may harmfully influence the ecosystem already at concentrations ≤ 1 μg L−1. The fast and easy quantification of DCF is becoming a subject of global importance. Fluorescence polarization immunoassay (FPIA) is a homogeneous mix-and-read method which does not require the immobilization of reagents. FPIA can be performed in one phase within 20–30 min, making it possible to analyse wastewater without any complicated pre-treatment. In this study, new tracermolecules with different structures, linking fluorophores to derivatives of the analyte, were synthesized, three homologous tracers based on DCF, two including a C6 spacer, and one heterologous tracer derived from 5-hydroxy-DCF. The tracer molecules were thoroughly assessed for performance. Regarding sensitivity of the FPIA, the lowest limit of detection reached was 2.0 μg L−1 with a working range up to 870 μg L−1. The method was validated for real wastewater samples against LC-MS/MS as reference method with good agreement of both methods.
Portable, antikörperbasierte Analysenverfahren für die Schadstofferfassung im Wasserkreislauf
(2021)
Die Wasseranalytik wird bestimmt von zwei Hauptbedarfen, einerseits der Erfassung der Gewässergüte und Grundwassergüte als Basis für die Bereitstellung einwandfreien Trinkwassers und zum anderen des Monitorings der Wasserqualität in den Prozessen der Wasseraufbereitung und der Abwasserreinigung. Für beide Anwendungsbereiche ist eine laborbasierte Analytik eher hinderlich, werden die Analysenergebnisse doch eigentlich vor Ort benötigt, um etwa Beprobungskampagnen rasch anpassen zu können. Des Weiteren werden die Daten auch schnell benötigt, um zeitnah in die technischen Prozesse einzugreifen. Organische Kontaminanten werden meist über chromatographische Verfahren, häufig gekoppelt mit einer massenspektrometrischen Detektion, in instrumentellen Labormethoden erfasst, und die hochauflösende Massenspektrometrie und die Non-target-Analytik haben viel zum Wissen über das Vorkommen, insbesondere von sogenannten „Emerging Contaminants“, beigetragen, sowie zum Verständnis der beteiligten Eintragspfade und Abbauwege. Moderne, portable Analysenmethoden und insbesondere Sensoren werden zukünftig aber ihren Platz in der Schadstofferfassung im Wasserkreislauf einnehmen. Dies gilt insbesondere für antikörperbasierte Analysenverfahren, da erst diese oft die nötige Selektivität und Sensitivität in die Detektionsmethoden einbringen.
Im Vorhaben „MARKERIA - Bestimmung von anthropogenen Markerkonzentrationen für die SARS-CoV-2 Quantifizierung mittels eines Hochdurchsatzverfahrens (ELISA)“ geht es um die Bestimmung von Carbamazepin, Diclofenac, Koffein und einer endogenen Gallensäure als potentielle Marker für die Kalibrierung der SARS-CoV-2 Quantifizierung im Abwasser. Der Vortrag wurde gehalten im Rahmen der 22. Sitzung des Begleitkreises des übergeordneten Projektes ESI-CorA. Er gab den Projektstand wieder, den die BAM bis dahin erzielt hatte. Die Marker waren in sämtlichen untersuchten Abwasser-Zulaufproben enthalten und zeigten spezifische Trends. Weitere Korrelationen müsse die weitergehende Datenauswertung ergeben.A