Solid-phase extraction cartridges

Solid-phase extraction cartridges (a) disk cartridge (b) column cartridge. 

The solid phase extraction cartridge (SPEC) is another somewhat vainglorious name given to a short inert plastic tube packed with an adsorbent, usually a reversed phase or an ion exchange resin. The particle size of the packing is often significantly larger than that used... 

This sample preparation involved, firstly, an extraction and the elimination of the solid matrix by filtration and, secondly, a concentration procedure employing a solid phase extraction cartridge. The compounds of interest were separated solely by dispersive interactions with the reversed phase. In the example given, the corn meal was spiked with the aflatoxins. 

This analysis depends on the use of a solid phase extraction cartridge to concentrate the herbicides directly from the pond water and the... 

A new technique has been developed to analyze a- and (3-endosulfan concentrations in human urine (Vidal et al. 1998). Samples are mixed with a buffer solution and then passed through solid phase extraction cartridges for analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). 

Betalains are vacuolar plant pigments. Hence their hydrophilic nature is comprehensible. Although they are slightly soluble in ethanol and methanol, water is the best snited solvent both for stability and solnbility reasons. In contrast to the antho-cyanins, the betalains are even more polar as can be demonstrated by shorter retention times in RP-HPLC and lower solubilities in alcoholic solutions. The varying polarities may also be beneficially used to separate anthocyanins from betalains on an RP-18 solid-phase extraction cartridge (Stintzing, unpublished data). 

Other techniques to improve throughput are instrumentation based and may involve multiple HPLC systems. The simplest method involves the automated use of solid phase extraction cartridges for sample cleanup followed by direct injection into the mass spectrometer [114], Coupling of multiple HPLC systems to one mass spectrometer allows one column to equilibrate and separate while another column to flow into the mass spectrometer. Multiple HPLC systems may be configured such that the mass spectrometer is only exposed to each serial HPLC eluent as the analyte of interest is eluted [115,116]. Although multiple H P LC-based methods may increase throughput, they also typically decrease sensitivity and may confound data workup and interpretation. 

Lopez-Avila V, Milanes J, Dodhiwala NS, et al. 1989. Cleanup of environmental sample extracts using florisil solid-phase extraction cartridges. J Chromatogr Sci 27(5) 209-220. 

Abu Ruz S, Millership J, Heaney L, McElnay J. 2003. Simple liquid chromatography method for the rapid simultaneous determination of prednisolone and cortisol in plasma and urine using hydrophilic lipophilic balanced solid phase extraction cartridges. J Chromatogr B Biomed Sci Appl 798(2) 193-201. 

Molins-Legua C, Campinc-Falco P, Sevillano-Cabeza A, Ped-r6n-Pons M. 1999. Urine polyamines determination using dansyl chloride derivatization in solid-phase extraction cartridges and HPLC. Analyst 124 477-482. 

Theobald N. 1988. Rapid preliminary separation of petroleum hydrocarbons by solid-phase extraction cartridges. Anal Chim Acta 204(1-2) 135-144. 

Soxhlet extraction clean up using 2 solid-phase extraction cartridges... 

Cleanup and concentration of corticosteroids from coextracted matrix constituents can also be accomplished using solid-phase extraction cartridges that contain nonpolar Cig (527, 535), or Cg sorbents (452), as shown in Table 29.17. In addition, Cig cartridges have been used to extract endogenous and synthetic corticosteroids from swine plasma (536), and to isolate cortisol from plasma or serum samples (537). Other workers employed conventional columns containing deactivated Florisil to isolate cortisol in milk (529) or fluoroprednisolone in bovine tissues (533). 

Solid-phase extraction membrane. Solid-phase extraction cartridge. [Courtesy Alhech Associates,... 

The volume of extract applied to the cartridge will depend mainly on sample quantity, its anthocyanin content, and the amount of sorbent packing in the column. Usually a sample volume of 5 to 10 ml is used for a Cl 8 solid-phase extraction cartridge containing 360 mg sorbent. 

C Crescenzi, A Di Corcia, G Passariello, R Samperi, Ml Turnes. Evaluation of two new examples of graphitized carbon blacks for use in solid-phase extraction cartridges. J Chromatogr A 733 41-55, 1996. 

To obtain clear solutions, the extracts are either filtered or centrifuged and the residues reextracted with the same solvents (108). Another possibility is to transfer the chlorophylls from the acetone phase into an ether phase by adding sodium chloride (114) or sodium sulfate (93). More recently acetone extracts were purified and fractionated with C18 solid-phase extraction cartridges, and dephytylated pigments were eluted with 70% acetone and phytylated pigments with 90% acetone (115). Often a concentrating of the pigment solution with a rota-evaporator under vacuum is necessary before analysis. Chlorophyll extracts should be analyzed as soon as possible, but if they have to be stored they must be kept in the cold and dark (107). 

When samples contain high quantities of interfering material (e.g., sugars, colloids), a sample-cleanup procedure is recommended. A sample preparation with solid-phase extraction cartridges (C18) was found to be quite useful and effective (180,193). Prior to HPLC analysis, all samples should be filtered through a 0.45-/zm or smaller membrane filter. 

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