Extraction discs

Crespo C, Marce RM, Borrull F. 1994. Determination of various pesticides using membrane extraction discs and gas chromatography mass spectrometry. J Chromatogr 670(1-2) 135-144. 

Dyes were extracted from spiked waters by membrane extraction discs containing 500 mg of poly(styrene-divinylbenzene). Dyes were separated in the HPLC systems as illustrated in Fig. 3.111. It was established that that APCI in negative ion mode was less sensitive than ES, and APCI in the positive-ion mode showed the lowest sensitivity [166],... 

In some designs, a glass fiber filter is supported above the extraction disc to prefilter samples containing particulates without clogging the extraction disc. Because of the rigid disc design, frits to support the extraction disc are not necessary. The polyethylene frits used in conventional SPEi columns may be a source of contamination (90) and have a large surface area and void volume. 

Extraction discs (0.5 mm thick, 25 to 90 mm diameter) constitute a variation of column-based SPE. These discs allow rapid extraction of large volumes of sample, which is not possible using a small column. The discs are made of bonded-phase silica particles, a few micrometres in diameter, trapped in a porous Teflon or glass fibre matrix. The discs are operated in a similar way to a paper filter on a vacuum flask. After extraction, the analyte is recovered by percolating a solvent through the filter. The major application of this technique is the isolation of trace amounts of compound dispersed in an aqueous medium. 

Hawthorne et al. [61] coupled subcritical water extraction of polycyclic aromatic hydrocarbons with extraction using styrene-divinyl benzene extraction discs. The discs can be stored in autosampler vials without loss of polycyclic aromatic hydrocarbons. 

McNally and Wheeler [364] used supercritical fluid extraction coupled to supercritical fluid chromatography to determine sulfonylurea herbicides in soil. Klatterback et al. [365,366] used supercritical fluid extraction with methanol-modified carbon dioxide followed by high-performance liquid chromatography with UV detection to determine sulfonylurea herbicides obtained on a Cis solid-phase extraction disc. Alternatively the determination was carried out by gas chromatography of the dimethyl derivatives of the sulfonylurea herbicides, employing an electron capture or a NP detector on the gas chromatograph. 

Albanis, T.A. and D.G. Hela (1995). Multi-residue pesticide analysis in environmental water samples using solid-phase extraction discs and gas chromatography with flame thermionic and mass-selective detection. J. of Chromatogr. A, 707 283-292. 

Extraction discs placed directly over the exit frit of the extraction cell have been used for the preconcentration of highly water-soluble acidic compounds from soil [39]. A strong anion-exchange (SAX) sorption disc facilitated not only preconcentration but also derivatization of the analytes. 

Howard AL, Taylor LT. Quantitative supercritical fluid extraction of sulfonylurea herbicides from aqueous matrices via solid-phase extraction discs. J Chromatogr Sci 1992 30 374-382. 

Extraction discs are suitable only for clean water samples. The organic compounds are removed from the water as it is filtered through the extracting disc and then the compounds are eluted with a suitable solvent. 

Eight micro liter of octane extraction solvent was placed inside a porous, polypropylene fiber following an 8 min analyte preconcentration step, 4 fil of extract was injected into a gas chromatograph Static subcritical water extraction was coupled with styrene-DVB (SDB-XC) extraction discs soil, water, and the SDB-XC disc are placed in a sealed extraction cell, heated to 250°C for 15 to 60 min, cooled, and the PAHs recovered from the disc with acetone/methylene chloride With a Soxhlet apparatus (18 h), by PLE (50 min at 100°C), SEE (1 h at 150°C with pure CO2), and subcritical water (1 h at 250°C, or 30 min at 300°C)... 

Solid-phase systems are available commercially, both in column and cartridge form, and also in the format of extraction discs. ... 

Saari-Nordhaus, R. Nair, LM. Anderson, J.M. Elimination of matrix interferences in ion chromatography hy the use of solid phase extraction discs. J. Chromatogr. 1994, 671, 159 163. 

M Empore extraction discs come with a wide variety of stationary phases spanning most imaginable applications. 

Sample preparation Condition a 3 mL 3M-Empore mixed-phase SPE extraction disc with 1 mL MeOH and 1 mL water. Mix 900 p,L serum with 100 tiL 3 p,g/mL IS in serum and 2 mL 100 mM pH 6.0 potassium dihydrogen phosphate buffer, add to the SPE disc, wash with 1 mL water, wash with 1 mL 1 M acetic acid, wash with 1 mL n-hexane, wash with 2 mL n-hexane ethyl acetate 50 50, wash with 1 mL MeOH, elute with 1 mL... 

Quantitative isolation of LAS from water is reported using Cig columns or extraction discs. In many matrices, LAS is the only anionic material extracted by Cig. Best recovery of adsorbed LAS is found with methanol, with incomplete recovery observed with acetonitrile, very incomplete recovery with ethyl acetate, and zero recovery with chloroform (51,52). However, if a large cationic salt like tetrabutylammonium chloride is added to the chloroform, LAS is easily eluted as the ion pair (53). Alkanesulfonates behave similarly, and this technique can be used to add additional selectivity to SPE, since interfering compounds can first be eluted from the resin with pure chloroform, followed by elution of LAS as an ion pair (53,54). Most cationics are not quantitatively isolated from water on Cig media. Most investigators use ion exchange media for SPE of cationics. 

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