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- Ethinylestradiol (2)
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- EE2 (1)
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In this work, we have developed and characterized a novel microfluidic immunoassay methodology for rapid and sensitive quantification of ethinylestradiol (EE2) in river water samples. The detection of EE2 was carried out using a competitive direct immunoassay method based on the use of anti-EE2 polyclonal antibodies immobilized on magnetic microspheres 3-aminopropyl-modified manipulated for an external removable magnet. The EE2 present in the water sample was allowed to compete with EE2-horseradish peroxidase (HPR) conjugated for the immobilized anti-EE2 antibody. The HPR, in the presence of hydrogen peroxide (H2O2) catalyzes the oxidation of catechol (Q) whose back electrochemical reduction was detected on gold electrode at 0.0 V. The response current obtained from the product of enzymatic reaction is inversely proportional to the amount of EE2 in the water sample. The electrochemical detection can be done within 1 min and total assay time was 30 min. The calculated detection limits for electrochemical detection and the ELISA procedure are 0.09 and 0.32 ng L-1 respectively and the intra- and inter-assay coefficients of variation were below 5.8%. Our electrochemical immunosensor showed higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method, which shows the potential for assessment of EE2 in river water samples.
The thermal shock behavior of three commercial-advanced ceramics (SSiC, MgO–PSZ, Al2O3) is characterized in air and vacuum applying a laser thermal shock. The available testing system permits the reproducible setting of defined temperature profiles in thin disks and allows a heating-up thermal shock in various media. Due to the accurate determination of the time- and space-resolved temperature distribution, the local stress state can be calculated as a function of time. It is shown that the thermal shock strength is highest for SSiC and lowest in Al2O3 with MgO–PSZ in between. The approach presented in this work allows quantifying the stress state at failure in terms of tangential tensile stress. The investigated environment does not affect the thermal shock resistance under the studied experimental conditions.
The synthetic estrogen ethinylestradiol (EE2) is an active component of oral contraceptives (OCs), considered as an endocrine disrupting compound (EDC). It is excreted from humans and released via sewage treatment plant effluents into aquatic environments. EDCs are any environmental pollutant chemical that, once incorporated into an organism, affects the hormonal balance of various species including humans. Its presence in the environment is becoming of great importance in water quality. This paper describes the development of an accurate, sensitive and selective method for capture, preconcentration and determination of EE2 present in water samples using: magnetic particles (MPs) as bioaffinity support for the capture and preconcentration of EE2 and a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs/GCE) as detection system. The capture procedure was based on the principle of immunoaffinity, the EE2 being extracted from the sample using the anti-EE2 antibodies (anti-EE2 Ab) which were previously immobilized on MPs. Subsequently the analyte desorption was done employing a sulfuric acid solution and the determination of the EE2 in the pre-concentrated solution was carried out by square wave voltammetry (SWV).
This method can be used to determine EE2 in the range of 0.03570 ng L-1 with a detection limit (LOD) of 0.01 ng L-1 and R.S.D. < 4.20%. The proposed method has been successfully applied to the determination of EE2 in water samples and it has promising analytical applications for the direct determination of EE2 at trace levels.