Solid phase extractants

Solid-Phase Extractions In a solid-phase extraction the sample is passed through a cartridge containing solid particulates that serve as the adsorbent material. For liquid samples the solid adsorbent is isolated in either a disk cartridge or a column (Figure 7.17). The choice of adsorbent is determined by the properties of the species being retained and the matrix in which it is found. Representative solid adsorbents... 

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

Selected Adsorbents for Solid-Phase Extraction of Liquid Samples... 

Two examples from the analysis of water samples illustrate how a separation and preconcentration can be accomplished simultaneously. In the gas chromatographic analysis for organophosphorous pesticides in environmental waters, the analytes in a 1000-mL sample may be separated from their aqueous matrix by a solid-phase extraction using 15 mb of ethyl acetate. After the extraction, the analytes are present in the ethyl acetate at a concentration that is 67 times greater than that in... 

In a solid-phase extraction the analytes are first extracted from their solution matrix into a solid adsorbent. After washing to remove impurities, the analytes are removed from the adsorbent with a suitable solvent. Alternatively, the extraction can be carried out using a Soxhlet extractor. 

This publication provides several examples of the use of solid-phase extractions for separating analytes from their matrices. Some of the examples included are caffeine from coffee, polyaromatic hydrocarbons from water, parabens from cosmetics, chlorinated pesticides from water, and steroids from hydrocortisone creams. Extracted analytes maybe determined quantitatively by gas (GC) or liquid chromatography (LG). 

Thurman, E. M. Mills, M. S. Solid-Phase Extraction Principles an Practice, Wiley NewYork, 1998. 

Two approaches have been used to separate the analyte from its matrix in particulate gravimetry. The most common approach is filtration, in which solid particulates are separated from their gas, liquid, or solid matrix. A second approach uses a liquid-phase or solid-phase extraction. 

Extraction Eiltering limits particulate gravimetry to solid particulate analytes that are easily separated from their matrix. Particulate gravimetry can be extended to the analysis of gas-phase analytes, solutes, and poorly filterable solids if the analyte can be extracted from its matrix with a suitable solvent. After extraction, the solvent can be evaporated and the mass of the extracted analyte determined. Alternatively, the analyte can be determined indirectly by measuring the change in a sample s mass after extracting the analyte. Solid-phase extractions, such as those described in Ghapter 7, also may be used. 

Saito described a quantitative spectrophotometric procedure for iron based on a solid-phase extraction using bathophenanthroline in a poly(vinyl chloride) membrane. ... 

Volatile analytes can be separated from a nonvolatile matrix using any of the extraction techniques described in Ghapter 7. Fiquid-liquid extractions, in which analytes are extracted from an aqueous matrix into methylene chloride or other organic solvent, are commonly used. Solid-phase extractions also are used to remove unwanted matrix constituents. 

A solid-phase extraction in which the solid adsorbent is coated on a fused-silica fiber held within a syringe needle. 

Description of Method. Fluoxetine, whose structure is shown in Figure 12.31a, is another name for the antidepressant drug Prozac. The determination of fluoxetine and its metabolite norfluoxetine. Figure 12.31 b, in serum is an important part of monitoring its therapeutic use. The analysis is complicated by the complex matrix of serum samples. A solid-phase extraction followed by an HPLC analysis using a fluorescence detector provides the necessary selectivity and detection limits. 

What is the purpose of including an initial solid-phase extraction ... 

Table 1. Samples Analyzed by Solid-Phase Extraction...

SOLID-PHASE EXTRACTION ON SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION TRACE IONS IN WATER WITH l-(2-PYRIDILAZO)-2-NAPHTOL... 

ATOMIC ABSORPTION DETERMINATION OF Cu(II), Cd(II), Zn(II), Pb(II) USING PRECONCENTRATION BY SOLID-PHASE EXTRACTION ON PROPYLTHIOETHYLEAMINE MODIFIED... 

SOLID PHASE EXTRACTION AND DETERMINATION OF TRACE AMOUNT OF Co + BY MODIFIED ANALCIME ZEOLITE WITH A NEW SCHIFF-BASE LIGAND... 

In order to one of the most effective separation and preconcentration procedure in trace metal analysis is solid phase extraction (SPE) of analyte. 

The liquid chromatography - tandem mass spectrometry (LC/MS/MS) technique was proposed for the determination of corticosteroids in plasma and cerebrospinal fluid (CSF, liquor) of children with leucosis. Preliminai y sample prepai ation included the sedimentation of proteins, spinning and solid-phase extraction. MS detection was performed by scanning selected ions, with three chai acteristic ions for every corticosteroids. The limit of detection was found 80 pg/ml of plasma. 

SOLID-PHASE EXTRACTION IN DETERMINATION OF ORGANIC COMPOUNDS IN WATER BY GC-MS Milyukin M.V. 

Prepai ative isolation of nonvolatile and semivolatile organic compounds fractions (hydrophobic weak acids, hydrophobic weak bases, hydrophobic neutrals, humic and fulvic acids) from natural and drinking waters in optimal conditions was systematically investigated by solid-phase extraction method with porous polymer sorbents followed by isolation from general concentrate of antropogenic and/or toxic semivolatile compounds produced in chlorination and ozonation processes. 

In recent decades the development of preconcentration steps to be implemented prior to analytical determinations of trace level compounds has been explored in considerable depth. With a view to eliminating or at least minimising the use of organic solvents used in conventional liquid-liquid extraction, other methodologies have been developed, such as membrane extraction, solid-phase extraction, solid-phase microextraction, etc. 

E.M. Thurman and M.S. Mills, Solid-phase Extraction Principles and Practice, Chemical Analysis Series Vol. 147, J. Wiley Sons, New York, 1998. ISBN 047161422X. 

Figure 2.12 Schematic representation of an on-line SPE-GC system consisting of three switching valves (VI-V3), two pumps (a solvent-delivery unit (SDU) pump and a syringe pump) and a GC system equipped with a solvent-vapour exit (SVE), an MS instrument detector, a retention gap, a retaining precolumn and an analytical column. Reprinted from Journal of Chromatography, AIIS, A. J. H. Eouter et al, Analysis of microcontaminants in aqueous samples hy fully automated on-line solid-phase extraction-gas chromatography-mass selective detection , pp. 67-83, copyright 1996, with permission from Elsevier Science.

S. Nelieu, M. Stobiecki and J. Einhom, Tandem solid-phase extraction of ati azine ozonation products in water , / Chromatogr. 866 195 - 201 (2000). 

Supercritical fluid extraction (SFE) and Solid Phase Extraction (SPE) are excellent alternatives to traditional extraction methods, with both being used independently for clean-up and/or analyte concentration prior to chromatographic analysis. While SFE has been demonstrated to be an excellent method for extracting organic compounds from solid matrices such as soil and food (36, 37), SPE has been mainly used for diluted liquid samples such as water, biological fluids and samples obtained after-liquid-liquid extraction on solid matrices (38, 39). The coupling of these two techniques (SPE-SFE) turns out to be an interesting method for the quantitative transfer... 

A method which uses supercritical fluid/solid phase extraction/supercritical fluid chromatography (SE/SPE/SEC) has been developed for the analysis of trace constituents in complex matrices (67). By using this technique, extraction and clean-up are accomplished in one step using unmodified SC CO2. This step is monitored by a photodiode-array detector which allows fractionation. Eigure 10.14 shows a schematic representation of the SE/SPE/SEC set-up. This system allowed selective retention of the sample matrices while eluting and depositing the analytes of interest in the cryogenic trap. Application to the analysis of pesticides from lipid sample matrices have been reported. In this case, the lipids were completely separated from the pesticides. 

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