Sorbent extraction

Sorbent extraction is very similar to HPLC in that it is based on the same separation processes and uses similar stationary phases. In this technique the analyte is 

Although PFE lacks a proven total concept for in-polymer analysis, as in the case of closed-vessel MAE (though limited to polyolefins), a framework for method development and optimisation is now available which is expected to be an excellent guide for a wide variety of applications, including non-polyolefinic matrices. Already, reported results refer to HDPE, LDPE, LLDPE, PP, PA6, PA6.6, PET, PBT, PMMA, PS, PVC, ABS, styrene-butadiene rubbers, while others may be added, such as the determination of oil in EPDM, the quantification of the water-insoluble fraction in nylon, as well as the determination of the isotacticity of polypropylene and of heptane insolubles. Thus PFE seems to cover a much broader polymer matrix range than MAE and appears to be quite suitable for R D samples. 

ASE is recognised as an official extraction method in US EPA SW-846 Method 3545 and has shown to be equivalent to standard EPA extraction technology in terms of recovery and precision. 

1 Hybrid Supercritical Fluid Extraction/ Enhanced Solvent Extraction 

Principles and Characteristics In an attempt to develop a unified sample preparation system for extraction of various matrix/analyte combinations Ashraf-Khorassani et al. [498] have described a hybrid supercritical fluid extraction/enhanced solvent extraction (SFE/ESE ) system to remove both polar and nonpolar analytes from various matrices. The idea is that a single instrument that can perform extractions via pure C02 solvent, and all gradients thereof affords 

A single SFE/ESE instrument may perform (i) pressurised C02 (SFE), (ii) pressurised C02/modifier and (iii) pressurised modifier (i.e. ASE /ESE , organic solvent) extractions. The division between SFE and ASE /ESE blurs when high percentages of modifier are used. Each method has its own unique advantages and applications. ESE is a viable method to conduct matrix/analyte extraction provided a solvent with good solvating power for the analyte is selected. Sample clean-up is necessary for certain matrix/analyte combinations. In some circumstances studied [498], SFE may offer a better choice since recoveries are comparable but the clean-up step is not necessary. 

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Air Collect on solid sorbent extract with diethyl ether in hexane GC/FPD No data 72-105 EPA1980d... 

Although SPE can be done in a batch equilibration similar to that used in LLE, it is much more common to use a small tube (minicolumn) or cartridge packed with the solid particles. SPE is often referred to as LSE, bonded phase or sorbent extraction SPE is a refinement of open-column chromatography. The mechanisms of retention include reversed phase, normal phase, and ion exchange. 

N. Simpson and K.C. van Home (eds), Varian Sorbent Extraction Technology Elandbook, Varian Sample Preparation Products, Harbor City, CA (1993). 

M. Zief and R. Kiser, Sorbent Extraction for Sample Preparation, J.T. Baker, Phillipsburg, NJ (1988). 

K. C. van Horne, Sorbent Extraction Technology, Analytichem International, Harbor City, CA (1985). 

Flow-injection (FI) on-line analyte preconcentration and matrix removal techniques greatly enhance the performance of atomic spectrometry [348], By using USN with membrane desolvation (MDS) as the interface, FI sorbent extraction can be directly coupled with ICP-MS for the analysis of organic solutions [349]. 

Wachs, T. and Henion, J. 2003. A device for automated direct sampling and quantitation from solid-phase sorbent extraction cards by electrospray tandem mass spectrometry. Anal. Chem. 75 1769. 

Several analytical methods for the determination of aldehydes in beer have been developed, and good results have been obtained using liquid-liquid extraction (2), distillation (3), or sorbent extraction (T). However, these methods are rather complicated and not highly selective. 

In 1985, Ruzicka and Hansen established the principles behind flow injection optosensing [13-15], which has subsequently been used for making reaction-rate measurements [16], pH measurements by means of immobilized indicators [17,18], enzyme assays [19], solid-phase analyte preconcentration by sorbent extraction [20] and even anion determinations by catalysed reduction of a solid phase [21] —all these applications are discussed in Chapters 3 and 4. Incorporation of a gas-diffusion membrane in this type of sensor results in substantially improved sensitivity (through preconcentration) and selectivity (through removal of non-volatile interferents). The first model sensor of this type was developed for the determination of ammonium [13] and later refined by Hansen et al. [22,23] for successful application to clinical samples. 

J. T. Baker, Application Guide, Vols. 1 and 2, Philipsburg, NJ, USA (1984). Sorbent Extraction Technology Handbook, Analytichem International Inc., Harbor City, CA, USA (1985). 

Analytical Methods. All of the sorbent extracts were analyzed by using GC-MS. The solutions were chromatographed on a 30-m X 0.32-mm i.d. Supelcowax 10 capillary column with a film thickness of 1 /um (Supelco). The Supelcowax 10 is a Carbowax PEG 20 M bonded-phase capillary column. The instrument conditions were as follows injector, 250 °C separator oven, 250 °C column over initial, 40 °C programmed to 250 °C at 6 °C/min linear velocity of helium carrier gas, 35 cm/s at 40 °C column head pressure, 6 lb/in.2 mass range, 33-333 amu scanned in 1-s intervals. Two-microliter aliquots were injected in the split mode at a 10-to-l split ratio. A typical chromatogram appears in Figure 1. 

Miro, M. and Frenzel, W., A critical examination of sorbent extraction preconcentration with spectrophotometric sensing in flowing systems, Talanta, 64, 290-301, 2004. 

Egorov, O., Grate, J. W., and Ruzicka, J., Automation of radiochemical analysis by flow injection techniques Am-Pu separation using TRU-resin sorbent extraction column, J. Radioanal. Nucl. Chem., 234, 231-235, 1998. 

Grate, J. W. and Egorov, O., Investigation and optimization of on-column redox reactions in the sorbent extraction separation of americium and plutonium using flow injection analysis, Anal. Chem., 70, 3920-3929, 1998. 

Sorbent extraction Exclusion of salts Limited solubility of human matter, partly irreversible sorption... 

Ruzicka, J. and Arndal, A. (1989) Sorbent extraction in flow-injection analysis and its application to enhanced atomic spectrometry. Anal. Chim. Acta, 216, 243-255. 

PME MASE Polymeric membrane extraction, Membrane-assisted sorbent extraction Nonporous Aqueous/polymer/aqueous Organic/polymer/aqueous Aqueous/polymer/organic... 

Y. Petit de Pena, M. Gallego, M. Valcarcel, On-line sorbent extraction, preconcentration and determination of lead by atomic absorption spectrometry, Talanta, 42 (1995), 211. 

Solid-phase extraction (SPE) is one of the most commonly used sorbent extraction techniques. The analytes are extracted together with interfering compounds with some similar characteristics by passing a usually aqueous sample through a plastic cartridge containing dispersed sorbent on a particulate support. A selective organic solvent is normally used to remove interferences and a different solvent is then employed to elute the retained analytes. This technique has a number of attractive features as compared with traditional solvent extraction. Thus, it is quite simple and inexpensive, can be automated and used in the field, and uses relatively small amounts of solvents. Particle-load... 

The Handbook of Sorbent Extraction Technology, 2nd ed., Varian Inc., Palo Alto, CA 1993. 

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