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Bezuayehu Tadesse

Bio: Bezuayehu Tadesse is an academic researcher from Debre Berhan University. The author has contributed to research in topics: Salting out & High-performance liquid chromatography. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.

Papers
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Journal ArticleDOI
TL;DR: Salting-out-assisted liquid-liquid extraction coupled with high-performance liquid chromatography was developed for selective extraction and preconcentration of five s-triazine herbicides and three...
Abstract: Salting˗out-assisted liquid–liquid extraction coupled with high-performance liquid chromatography was developed for selective extraction and preconcentration of five s-triazine herbicides and three...

11 citations


Cited by
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Journal ArticleDOI
TL;DR: The development of analytical methodologies and criticalities connected to determine pesticide residues in water matrices, including sampling, sample preparation approaches, instrumental analyses and specific applications emphasising those works published after 2015 are illustrated.
Abstract: In this review, we examined the European legislative context on water protection concerning pesticide residues monitoring and the relevant National Action Plans and strategies that were undertaken in European countries to better identify and manage the problem in water bodies. Furthermore, we illustrated the development of analytical methodologies and criticalities connected to determine pesticide residues in water matrices, including sampling, sample preparation approaches, instrumental analyses and specific applications emphasising those works published after 2015. Details about sampling strategies, analytical feasibility, official methods, degradation products and behaviour in the environment for a subset of 160 pesticides are also provided.

30 citations

Journal ArticleDOI
TL;DR: A rapid, simple, and cheap analytical method, based on salting-out assisted liquid-liquid extraction coupled with UHPLC MS/MS detection for the accurate determination of CAP in honey to be used in routine analyses is proposed.
Abstract: Honey is a natural food widely consumed due to its high content in nutrients and bioactive substances. In order to prevent hive infections, xenobiotics such as pesticides and antibiotics are commonly used. Chloramphenicol (CAP) is a broad-spectrum antibiotic used to treat honeybee larvae diseases. However, CAP has toxic and nondose-dependent effects in sensitive subjects; for this reason, its use has been prohibited in food-producing animals, such as the honeybee. In this study, we proposed a rapid, simple, and cheap analytical method, based on salting-out assisted liquid-liquid extraction coupled with UHPLC MS/MS detection for the accurate determination of CAP in honey to be used in routine analyses. The parameters that influence the extraction efficiency have been optimized using an experimental design in order to maximize the recovery of the analyte by reducing the matrix effects. Therefore, the developed method was internally validated according to the 2002/657/EC Decision guidelines and applied to the analysis of 96 honey samples.

16 citations

Journal ArticleDOI
TL;DR: In this paper, two types of polysiloxane polyether (DC 193C and OFX 0309) were studied to investigate the effectiveness of these surfactants toward atrazine in CPE method.
Abstract: Cloud point extraction (CPE) – spectrophotometric method had been adopted for the separation of atrazine using the non-ionic silicone surfactant, polysiloxane polyether, as a new approach of atrazine extractor in CPE. There were two types of polysiloxane polyether (DC 193C and OFX 0309) studied to investigate the effectiveness of these surfactants toward atrazine in CPE method. Various effects of operating parameters such as the concentration of surfactant and atrazine, addition of salt and change of temperature and pH on the extraction of atrazine have been studied in detail to find the optimum conditions. The limit of detections (LODs) and quantifications (LOQs) were in the range of 0.09–0.59 μg L−1 and 0.31–1.95 μg L−1 in water samples, respectively. The method recoveries at two spiked levels were 84–105% (CPE-OFX 0309) and 59–69% (CPE-DC 193C) with good correlation of determination (R2) ranging from 0.9927–0.9993 for both methods. The Langmuir isotherm has been used for solubilisation study of surfactant and atrazine. The thermodynamic parameters have been determined such as Gibbs free energy (ΔG°) which increases with temperature, value of enthalpy (ΔH°) and value of entropy (ΔS°) which increase with the surfactant hydrophobicity.

12 citations

Journal ArticleDOI
TL;DR: In this paper, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples.
Abstract: In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 - 100 μg/L (carbaryl), 8 - 100 μg/L (atarzine), 7 - 100 μg/L (propazine) and 9 - 100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R2) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.

12 citations

Journal ArticleDOI
TL;DR: This research presents a novel probabilistic procedure that allows for direct measurement of the response of the immune system to earthquake-triggered landsliding.
Abstract: A new cloud point methodology was successfully used for the extraction of carcinogenic pesticides in milk samples as a prior step to their determination by spectrophotometry. In this work, non-ioni...

3 citations