Do you want to buy antibiotics online without prescription? - This is pharmacy online for you!

Replace this text with the title

Development of Ultrasonic Assisted Extraction Method of Emerging
Contaminants in Freshwater Sediments
Diana Nara Ribeiro de Sousa1, Guilherme Martins Grosseli1, Mariele Barboni Campanha1, Renato
Lajarim Carneiro1, Antonio Aparecido Mozeto1, Pedro Sérgio Fadini1
1Universidade Federal de São Carlos – UFSCar, Rod. Washington Luís km 235, São
The determination of emerging
contaminants in water, soils, sediments, sludge and
suspended matter has become a requisite stage for the
partition evaluation of these contaminants. For
sediment samples, extraction methods include
microwave assisted extraction (MAE) and ultrasound assisted extraction (UAE). Among these, UAE has been shown very promising due to its lower cost, easy processing and availability [1]. In this work, Fig. 1: Observed recoveries values for the three
different procedures of extraction by ultrasound were tested to extract 11 emerging contaminants. In an attempt to increase the atenolol and propranolol recoveries, it was investigated the effect of pH Methods: Methanol, water, acetone, ethyl acetate
variation. Recoveries of propanolol and atenolol at and different mixtures of these were used as pH 2 were 70% and 2.6%, respectively (E3) and at extraction solvents. Firstly, 2.00g of dry sediment, pH 8 both compounds presented recoveries around was spiked to 100 ng.g-1 with a solution containing 40% without compromising the quality of results. all target compounds and respective deutered and The exposition time to the ultrasound was optimized submitted to successive steps of extraction in three in 10 minutes and experiments at different levels of different experiments. In the first one, samples were spiking were performed with this time and pH 8. ultrasonicated with 5 mL of methanol, 5 mL methanol:water (1:1) and 2 mL of acetone Table 1: Observed recovery values at different levels
homogenized in vortex, ultrasonicated for 30 min and Compound
centrifuged at 5000 rpm for 5 min. The supernatants of each sample were combined, homogenized and diluted to 250 mL with Milli-Q water. The other two experiments involved differentiation with respect to steps with 2 mL of ethyl acetate and 3 mL of methanol:water (1:2, pH 2), respectively. The clean- up procedure was carried out using Oasis HLB (200 mg, 6 cc) cartridges, conditioned with 2x5 mL of methanol and 2x5 mL of Milli-Q water. After extraction, cartridges were rinsed with 2x4 mL Milli- Q water and dried for 30 min. Elution was performed Discussion: According to results, the developed
methanol:acetone (1:1). The extract was evaporated methodology allows the simultaneous determination under nitrogen stream and reconstituted with 1 mL of of 11 emerging contaminants in freshwater sediments methanol:water (25:75). Analyses were performed in showing 9 recoveries values in accordance with the a TQD Waters system. In the next stage, it was Council Directive 96/23/EC and standard deviation evaluated different ultrasound exposition times, the lower than 10% in all the replicates, pointing the influence of pH and recoveries values at three potential applicability of the proposed method. different levels of spiking (10, 50 and 100 ng.g-1). Acknowledgements:
Results: The experiments E1 and E2 presented
recoveries values above 60% for all compounds References: [1] Tadeo et al. (2012) Cent. Eur. J.
Chem.10(3) : 480-520 .


Asian journal of drug metabolism and pharmacokinetics

Asian Journal of Drug Metabolism and Pharmacokinetics Copyright by Hong Kong Medical Publisher ISSN 1608 2281 2004; 4(2): 119-122 Study on bioequivalence of pioglitazone hydrochloride tablets in healthy Chinese volunteers Hua Zhang, Xue-Qing Wang, Xuan Zhang, Qiang Zhang, Qi Yin* and Ke-Xin Li* Department of Pharmaceutics, School of Pharmaceutical Sciences, Peking Unive

Microsoft word - tempprint.doc

DATE REPORT ISSUED 22/03/2011 PLEASE FIND ENCLOSED OUR REPORT REFERENCE ALC E : 133257 : 0211BUREAU VERITAS CONSUMER PRODUCTS SERVICES UK LTD SAMPLE RETENTION POLICY Unless otherwise agreed in writing, samples will be retained for a minimum period of 28 days and then disposed of at BureauVeritas Consumer Products Services UK Ltd’s discretion. Bureau Veritas Consumer Products Serv

Copyright © 2010-2014 Medical Pdf Finder