Phenols solid-phase extraction

Figure 13.15 Chromatograms obtained by on-line ti ace enrichment of 50 ml of Ebro river water with and without the addition of different volumes of 10% Na2S03 solution for every 100 ml of sample (a) blank with the addition of 1000 p.1 of sulfite (b) spiked with 4 p.g 1 of the analytes and 1000 p.1 of sulfite (c) spiked with 4 p.g 1 of the analytes and 500 p.1 of sulfite (d) spiked with 4 p.g 1 of the analytes without sulfite. Peak identification is as follows 1, oxamyl 2, methomyl 3, phenol 4, 4-niti ophenol 5, 2,4-dinitrophenol 6, 2-chlorophenol 7, bentazone 8, simazine 9, MCPA 10, atrazine. Reprinted from Journal of Chromatography, A 803, N. Masque et ai, New chemically modified polymeric resin for solid-phase extraction of pesticides and phenolic compounds from water , pp. 147-155, copyright 1998, with permission from Elsevier Science.

E. Pocumll, R. M. Marce, F. Bonnll, J. L. Bernal, L. Toribio and M. L. Serna, On-line solid-phase extraction coupled to supercritical fluid chromatography to determine phenol and nitrophenols in water , ]. Chromatogr. 755 67-74 (1996). 

In a related approach from the same laboratory, the perfluorooctylsulfonyl tag was employed in a traceless strategy for the deoxygenation of phenols (Scheme 7.82) [94], These reactions were carried out in a toluene/acetone/water (4 4 1) solvent mixture, utilizing 5 equivalents of formic acid and potassium carbonate/[l,T-bis(diphe-nylphosphino)ferrocene]dichloropalladium(II) [Pd(dppf)Cl2] as the catalytic system. After 20 min of irradiation, the reaction mixture was subjected to fluorous solid-phase extraction (F-S PE) to afford the desired products in high yields. This new traceless fluorous tag has also been employed in the synthesis of pyrimidines and hydantoins. 

De la Torre-Carbot K, Jauregui O, Gimeno E, Castellote AI, Lamuela-Raventos RM and Lopez-Sabater M. 2005. Characterization and quantification of phenolic compounds in olive oils by solid-phase extraction, HPLC-DAD, and HPLC-MS/MS. J Agric Food Chem 53(11 ) 4331 —4340. 

Michalkiewicz A, Biesaga M and Pyrzynska K. 2008. Solid-phase extraction procedure for determination of phenolic acids and some flavonols in honey. J Chromatogr A 1187( 1-2) 18-24. 

L6pez-Roldan P., de Alda M.J.L., and Barcelo D., 2004. Simultaneous determination of selected endocrine disrupters (pesticides, phenols and phthalates) in water by in-field solid-phase extraction (SPE) using the prototype PROFEXS followed by online SPE (PROSPEKT) and analysis by liquid chromatography-atomspheric pressure chemical ionization-mass spectrometry. Anal Bioanal Chem 378 599. 

Wissiack R., Rosenberg E., and Grasserbauer M., 2000. Comparison of different sorbent materials for online solid-phase extraction with liquid chromatography-atmospheric pressure chemical ionization mass spectrometry of phenols. J Chromatogr B 896 159. 

The crude oil used by Bennett and Barter (1997) was a typical North Sea oil generated from Upper Jurassic, Kimmeridge clay formation source rocks. The alkylphenol distribution in a sample of (Miller) crude oil, determined using solid phase extraction (SPE), is shown in Fig. 16.21. The crude oil is dominated by phenol and cresol and contains appreciable quantities of dimethylphenols. The concentrations of 2,3-, 3,4-, and 3,5-dimethylphenol also include a contribution from 2-, 3-, and 4-ethylphenols, because they coelute under the conditions employed (Bennett et ah, 1996). 

In some instances, combinations of Cig and silica columns are also used for better purification of the crude extracts (431, 445). A combination of Cg, silica, and amino solid-phase extraction columns has been successfully employed to fractionate anabolic and catabolic steroid hormone residues from meat in polar and nonpolar neutral and phenolic compounds, and to purify further each fraction effectively (452). Another combination of two solid-phase extraction columns, one using a graphitized carbon black sorbent and the other Amberlite resin in the hydroxyl form, allowed neutral anabolics to be isolated and separated from acidic anabolics and their metabolites (453). A combination of basic alumina column placed in tandem with an ion-exchange column has also been applied for the purification of the crude extracts in the determination of diethylstilbestrol and zeranol (427), and estradiol and zeranol in tissues (450). 

Phenolic acids are ionized at pH 7.0 and are un-ionized at pH 2.0. This property allows for solid-phase extraction of neutral polyphenolics at pH 7.0 and acidic polyphenolics at pH 2.0 to prevent interference. In this protocol, polyphenolics isolated as neutral and acidic fractions using pH adjustments are analyzed by reversed-phase HPLC in a thermostatically controlled environment. 

Retention times of the peaks are subject to the particular type of column. The acidic fraction from solid-phase extraction consists of phenolic acids such as cis-coutaric, trans-coutaric, and trans-caftaric acids. Isocratic elution is suitable because of the limited number of compounds found in the acidic fraction. Analysis of the acidic fraction is completed within 30 min. See Figure 11.3.1 for an HPLC chromatogram of the acidic polyphenolics isolated from Niagara grapes. 

N. Masque, M. Galia, R. M. Marce and F. Borrull, New chemically modified polymeric resin for solid-phase extraction of pesticides and phenolic compounds from water , / Chromatogr. 803 147-155 (1998). 

Ohlenbusch, G., M. Kumke, and F. H. Frimmel. 2000. Sorption of phenols to dissolved organic matter investigated by solid phase extraction. Science of the Total Environment 253 63. 

Patsias, J. and E. Papadopoulou-Mourkidou. 2000. Development of an automated on-line solid-phase extraction-high-performance liquid chromatographic method for the analysis of aniline, phenol, caffeine and various selected substituted aniline and phenol compounds in aqueous matrices. J. Chromatogr. A 904 171-188. 

A recent development is to combine filtration with solid-phase extraction separation. These filter modules contain a unique silica gel membrane that binds up to 20 pg of DNA in the presence of a high concentration of chao-tropic salt and allow eventual elution in a small volume of low-salt buffer. They also contain an asymmetric laminar membrane with a gradation of pore sizes for efficient removal of material precipitated in the lysate. Such membrane filters eliminate time-consuming phenol-chloroform extraction and alcohol precipitation. The impregnation of silica in the membrane matrix also prevents the problems associated with loose resins and slurries. High-purity plasmid DNA eluted from such modules is ready to use and often needs no further precipitation, concentration, or desalting. 

Arraez-Roman, D., GomezCaravaca, A. M., Gomez-Romero, M., Segura-Carratero, A., and Fernandez-Gutierrez, A. (2006). Identification of phenolic compounds in rosemary honey using solid-phase extraction by capillary electrophoresis-electrospray ionization mass spectrometry. ]. Pharm. Biomed. Anal. 41,1648-1656. 

Phenols — — Preconcentrated by solid phase extraction Spectrofluorometric Trace [70]... 

Glowniak, K., Zgorka, G., and Kozyra, M. 1996. Solid-phase extraction and reversed-phase high-performance liquid chromatography of free phenolic acids in some Echinacea species. J. Chromatogr. A 730, 25-29. 

Analytical methods used for determining DNOC in environmental samples are given in Table 6-2. Most of the methods for products, waters, soils, and sludges rely on extraction of DNOC from an acidified matrix acidification minimizes dissociation of the phenolic hydrogen and thus facilitates extraction into an organic solvent or adsorption onto a solid phase extraction medium. The influence of pH on the adsorption of DNOC to humic materials in coal waste waters has been studied (Porschmann and Stottmeister 1993) and significant adsorption was found to occur at pH 7 but not... 

Hagan DF, Markell CG, Wsted EE. 1993. Solid-phase extraction of phenols using membranes loaded with modified polymeric resins. J Chromatog 641 57-61. 

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