Solid-phase extraction microextraction

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. 

The most widely employed techniques for the extraction of water samples for triazine compounds include liquid-liquid extraction (LLE), solid-phase extraction (SPE), and liquid-solid extraction (LSE). Although most reports involving SPE are off-line procedures, there is increasing interest and subsequently increasing numbers of reports regarding on-line SPE, the goal of which is to improve overall productivity and safety. To a lesser extent, solid-phase microextraction (SPME), supercritical fluid extraction (SEE), semi-permeable membrane device (SPMD), and molecularly imprinted polymer (MIP) techniques have been reported. 

The need to understand the fate of pesticides in the environment has necessitated the development of analytical methods for the determination of residues in environmental media. Adoption of methods utilizing instrumentation such as gas chro-matography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), liquid chromatography/tandem mass spectrometry (LC/MS/MS), or enzyme-linked immunosorbent assay (ELISA) has allowed the detection of minute amounts of pesticides and their degradation products in environmental samples. Sample preparation techniques such as solid-phase extraction (SPE), accelerated solvent extraction (ASE), or solid-phase microextraction (SPME) have also been important in the development of more reliable and sensitive analytical methods. 

Diffusive sampler Membrane extraction (MESI) Liquid-liquid extraction (LLE) Solid-phase extraction (SPE) SPE-PTV-GC Solid-phase microextraction (SPME) Headspace GC (SHS, DHS) Large-volume injection (LVI) Coupled HPLC-GC Membrane extraction (MESI) Difficult matrix introduction (DMI) Conventional solvent extraction methods 1 Pressurised solvent extraction methods Headspace GC (SHS, DHS) Thermal desorption (TD, DTD) Pyrolysis (Py) Photolysis Photon extraction (LD) Difficult matrix introduction (DMI)... 

Solid Phase Sorbents. Solid Phase Extraction Formats. Automated Solid Phase Extraction. Solid Phase Microextraction. Applications of SPE and SPME. 

In the past two decades quite a few new techniques have emerged for the treatment of aqueous samples prior to organic analysis. Perhaps the most important development is that of solid-phase extraction (SPE), which has successfully replaced many off-line steps. This technique can be considered to have introduced a genuine new era in sample handling [1]. The many varieties in which the technique is available and can be applied have made it the key step in handling of aqueous samples. Among the successful varieties are solid-phase microextraction (SPME), matrix solid-phase dispersion, disk extraction and immunosorbent extraction. Several reviews covering these topics have appeared in the literature in the past decade (see e.g. Refs. [2,3] for nonylphenol... 

Experiments to identify disinfection by-products (DBFs) have been carried out using two different procedures. In the first, natural waters (e.g., river, lake) are reacted with the disinfectant, either in a pilot plant, an actual treatment plant, or in a controlled laboratory smdy. fii the second type of procedure, aquatic humic material is isolated and reacted with the disinfectant in purified water in a controlled laboratory study. This latter type of study is relevant because humic material is an important precursor of THMs and other DBFs. Aquatic humic material is present in nearly all natural waters, and isolated humic material reacts with disinfectants to produce most of the same DBFs found from natural waters. Because DBFs are typically formed at low levels (ng/L-pg/L), samples are usually concentrated to allow for DBF detection. Concentration methods that are commonly used include solid phase extraction (SFE), solid phase microextraction (SFME), liquid-liquid extraction, and XAD resin extraction (for larger quantities of water) [9]. 

Fig. 18.1 Systems used to absorb aroma compounds from samples for analytical purposes, a Traps loaded with various adsorbents [4]. b Solid-phase extraction (disk in a holder assembly) [5]. c Solid-phase microextraction (coated needle inserted in sample) [5]. d Twister (1 -cm length) [4]. (Courtesy of GERSTEL GmbH and Co. KG)...

Some of the newer procedures use the same basic principles as the older extraction methods but provide fast and easy-to-use options and generally consume less organic solvent. For the most part, they have higher initial purchase price than the traditional methods. Examples include supercritical fluid extraction, accelerated solvent extraction, and automated solid-phase extraction and microextraction. Modular systems are now readily available that automate these proce-... 

W. M. Mullett, P. Martin, and J. Pawliszyn, In-Tube Molecularly Imprinted Polymer Solid-Phase Microextraction for the Selective Determination of Propranolol, Anal. Chem. 2001, 73, 2383 N. Masque, R. M. Marce, F. Borrull, P. A. G. Cormack, and D. C. Sherrington, Synthesis and Evaluation of a Molecularly Imprinted Polymer for Solid-Phase Extraction of 4-Nitrophenol from Environmental Water, Anal. Chem. 2000, 72, 4122. 

Tamayo FG, Turiel E, Martin-Esteban A (2007) Molecularly imprinted polymers for solid-phase extraction and solid-phase microextraction recent developments and future trends. J Chromatogr A 1152(l-2) 32 i0... 

Aqueous samples are extracted with hexane or with methylene chloride by liquid-liquid extraction using a separatory funnel or a mechanical shaker, or by microextraction. Aqueous samples can also be extracted by solid phase extraction using a C-18 cartridge. Selection of sample volume should be based on the extent of sample concentration that may be needed to achieve the required detection level in the analysis, as well as the use of packed or capillary column. A larger sample concentration is required for packed column than that for capillary column analysis. U.S. EPA recommends the extraction of 1 L sample to a final volume of 1 mL for wastewater analysis performed on a packed column. For the analysis of potable water by GC-ECD on a capillary column, concentration of a 35-mL... 

Among the numerous techniques for separating and enriching organic compounds from water samples, the following are worthy of mention solid-phase extraction (SPE), solid-phase microextraction (SPME), liquid-liquid extraction (LLE), and lyophilization. 

Fattahi, N., S. Samadi, Y. Assadi, and M. R. M. Hosseini. 2007. Solid-phase extraction combined with dispersive liquid-liquid microextraction-ultra preconcentration of chlorophenols in aqueous samples. J. Chromatogr. A 1169 63-69. 

Gaynor, J.D., D.A. Cancilla, G.R.B. Webster, et al. 1996. Comparative solid phase extraction, solid phase microextraction, and immunoassay analyses of metolachlor in surface runoff and tile drainage. J. Agric. Food Chem. 44 2736-2741. 

Sorbent/ solid phase Solid phase extraction (SPE) Solid phase microextraction (SPME) Stir bar sorptive extraction (SBSE) INCAT/OTT/in-tube-SPME SPDE Headspace-solid phase microextraction (HS-SPME) Headspace stir-bar sorptive extraction (HS-SBSE) Purge-and-sorbent trapping Spray-and-sorbent trapping... 

Lopez-Bianco, M.C., S. Blanco-Cid, B. Cancho-Grande, and J. Simal-Gandara. 2003. Application of single-drop microextraction and comparison with solid-phase microextraction and solid-phase extraction for the determination of a- and [1-endosulfan in water samples by gas chromatography-electron-capture detection. J. Chromatogr. A 984 245-252. 

LLE liquid-liquid extraction, SPE solid phase extraction, LPME liquid-phase microextraction, ESI electrospray ionization, APCI atmospheric pressure chemical ionization, SSI sonic spray ionization, Q quadrupole, QqQ triple quadrupole, TOF time-of-flight, IT ion trap, IS internal standard, CV coefficient of variation, MRE mean relative error, LOD limit of detection, LLOQ lower limit of quantification... 

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