Search Results

1 - 10 of 193 items :

  • "solid phase extraction" x
Clear All

References Barciela-Alonso MC, Otero-Lavandeira N, Bermejo-Barrera P (2017) Solid phase extraction using molecular imprinted polymers for phthalate determination in water and wine samples by HPLC-ESI-MS. Microchem. J. 132: 233-237. Büyüktuncel E, Porgali E, Özkara S (2018) Catechinmolecularly imprinted cryogel for determination of catechin in red wines by HPLC-DAD–Fluorescence detector. Acta Chromatogr. 30: 54-61. Canas S. (2017) Phenolic compounds and related properties of aged wine spirits: Influence of barrel characteristics. A Review. Beverages 3: Article

-46. 12. Adaway JE, Keevil BG. Therapeutic drug monitoring and LC-MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 883-884: 33-49. 13. Chen L, Wang H, Zeng Q, Xu Y, Sun L, Xu H, et al. Online coupling of solid-phase extraction to liquid chromatography - a review. J Chromatogr Sci 2009; 47: 614-23. 14. Gaziev J, Nguyen L, Puozzo C, Mozzi AF, Casella M, Per - rone Donnorso M, et al. Novel pharmacokinetic behavior of intravenous busulfan in children with thalassemia undergoing hematopoietic stem cell transplantation: a prospective evaluation of pharmacokinetic

Abstract

Herein, we present a simple and rapid high performance liquid chromatographic (HPLC) method with UV-detection for the direct determination of diazepam in whole blood and serum that can be used for monitoring diazepam levels in clinical samples analysis. The isolation of diazepam and the internal standard bromazepam from serum and whole blood samples was performed using solid phase extraction method with RP select B cartridges. The analytes were separated employing a reversed phase C8 column with a mobile phase composed of 0.1 % (V/V) triethylamine in water (pH 3.5) and acetonitrile (63:37, V/V). UV detection was carried out at 240 nm. Linearity was achieved in the range from 10.0-1000.0 ng/ml for serum and whole blood. The method was applied to spiked and real biological samples after an oral administration of 10 mg diazepam. In conclusion, the proposed method is simple, rapid and provides efficient clean-up of the complex biological matrix and high recovery of diazepam.

with diode array detector and mass spectrometry. J. Chromatogr. A, 1216, 2009, 2111 - 2117. TAMAYO, F.G., TURIEL, E., MARTÍN-ESTEBAN, A.: Molecularly imprinted polymers for solid-phase extraction and solid-phase microextraction: Recent developments and future trends. J. Chromatogr. A, 1152, 2007, 32-40. WANG, W., TANG, J., WANG, S., ZHOU, L., HU, Z.: Method development for the determination of coumarin compounds by capillary electrophoresis with indirect laser-induced fluorescence detection. J. Chromatogr. A, 1148, 2007, 108-114. ZHOU, T., XIAO, X., LI, G., ZONG

Abstract

Selective molecularly imprinted polymers (MIPs) with bisphenol A as template were synthesized using the non-covalent imprinting approach. MIPs were prepared using thermally initiated polymerization with 1,1’-azobis(cyclohexanecarbonitryle) (ACHN) as initiator and ethylene glycol dimethacrylate (EDMA) as a cross-linking agent. The tested functional monomers included methacrylic acid, acrylamide, and 4-vinylpyridine. The selectivity of the BPA-MIP for the solid phase extraction of bisphenol A was tested in samples containing other related alkylphenols. The polymers prepared in acetonitrile using methacrylic acid or acrylamide as monomer showed the highest selectivity towards target analyte (the selectivity ratio 8:1, respectively for MIP and NIP). The proposed procedure has been proven to be an effective for selective extraction of bisphenol A in aqueous samples (recoveries over 85%) enabling detection and quantification limits of 25 and 70 μg/dm3, respectively based on 10 cm3 of sample volume, with relative standard deviations (RSD) lower than 6%. The obtained molecularly imprinted material showed interesting properties for selective extraction and preconcentration of studied analyte from large volumes of aqueous samples without any problems of cartridge clogging.

Development and validation of a bioanalytical LC-UV method with solid-phase extraction for determination of valproic acid in saliva

A bioanalytical HPLC method with UV detection for the determination of the antiepileptic drug valproic acid in human saliva has been developed and validated. Saliva represents an alternative matrix for therapeutic monitoring of antiepileptic drugs due to the increasing interest in free drug concentration. The proposed method involved solid-phase extraction for sample preparation and yielded very good mean recoveries of 99.4 % and 97.9 % for valproic acid and IS, respectively. The calibration function for valproic acid was linear over the concentration range of 1.0-50.0 μg mL-1 (R 2 = 0.9989). Within-run and between-run precision and accuracy were studied at four concentrations and RSDs were less than 7.3 and 2.2 %, while accuracy values were higher than 96.8 and 97.5 %, respectively. The described method provides sensitivity, linearity, precision, accuracy and is suitable for analyses of valproic acid in saliva samples.

. 124, 5962-5963. DOI: 10.1021/ja026290w. 21. Liu, J., Jiang, G., Chi, Y., Cai, Y., Zhou, Q. & Hu, J. (2003). Use of ionic liquid for liquid-phase microextraction of polycyclic aromatic hydrocarbons. Anal. Chem.75, 5870-5876.DOI: 10.1021/ac034506m. 22. Bi, W., Tian, M. & Row, K.H. (2010). Solid-phase extraction of matrine and oxymatrine from Sophora Flavescens Ait using amino-imidazolium polymer. J. Sep. Sci. 33, 1739-1745. DOI: 10.1002/jssc.200900835. 23. Zhu, S., Yu, P., Lei, M., Tong, Y., Zheng, L., Zhang, R., Ji, J., Chen, Q., Wu, Y. (2013). Investigation of the

. Baxter, A. Rampey, G. Rushton, Y. Chen and K. Shimizu, Characterization of the heterogeneous binding site affinity distribution in molecularly imprinted polymers, J. Chromatogr. B 804 (2004) 141-149; DOI: 10.1016/ j.jchromb. 2004.01.064 14. A. Lagha, N. Adhoum and L. Monser, A molecularly imprinted polymer for the selective solid- -phase extraction of ibuprofen from urine samples, Open Anal. Chem. J . 4 (2011) 7-13; DOI: 10.2174/1875038901004010007. 15. R. Umpleby, S. Baxter, M. Bode, J. Berch, R. Shah and K. Shimizu, Application of the Freundlich adsorption

Determination of PAH in the Black Sea Water by GC/MS Following Preconcentration with Solid-Phase Extraction

Determination of PAHs in marine coastal waters has to be carried out with great care to avoid serious losses occurring during the sampling and storage stage. This is due to the hydrophobic properties of PAHs, and their tendency to be adsorbed to surfaces they are in contact with, including suspended particulate matter. The best technique to separate PAHs is gas chromatography with mass spectrometer. Because of low concentration levels to be quantified in water samples, an enrichment step is needed before chromatographic analysis. For PAHs, several preconcentration techniques have been used, but the most concentration technique is solid-phase extraction (SPE). The main objective of this work is to adapt and implement a relatively simple and rapid method for gas chromatographic determination of individual PAHs in samples of coastal and running waters. The present work analyses the yield and precision of extraction of PAHs by solid phase extraction with using different sorbents for SPE (Bond Elut: C18 and Plexa SPE discs), the two most common methods used for aqueous samples.

, PŁOCHARSKI W: Chemical composition of French and Polish cloudy apple juices. J. Hortic. Sci. & Biotech., ISAFRUIT Special Issue, 68–74, 2009. MELO LFC, COLLINS CH, JARDIM ICSF: High-performance liquid chromatographic determination of pesticides in tomatoes using laboratory-made NH 2 and C 18 solid-phase extraction materials. J. Chromatogr. A., 1073(1) 75-81, 2005. MERCER GE: Determination of 112 halogenated pesticides using gas chromatography/mass spectrometry with selected ion monitoring. J AOAC Int. , 88(5) 1452-1462, 2005. PICO Y, BLASCO C, FONT G: Environmental and