Solid-phase microextraction parameters

Wennrich [167] optimised important accelerated solvent extraction parameters, such as extraction temperature and time, using a spiked wetland soil. The effect of small amounts of organic modifiers on the extraction yields was studied. An extraction temperature of 125 °C and ten-minute extractions performed three times proved optimal. Two accelerated solvent extraction-solid-phase microextraction procedures without and with an organic modifier (5% acetonitrile) were evaluated with respect to precision and detection limits. 

Information for acertain parameter not available, if not given, na, not available DI, deionized water Cl, chemical ionization BCD, electron capture detector El, electron impact ionization FID, flame ionization detector MS, mass spectrometer MtBE, methyl tert-butylether MTBSTE, n-(tert-butyldimethylsilyl)-Wmethylfluoracetamide PDAM, 1-pyrenyldiazomethane PFBBr, pentafluorobenzyl bromide PEBOH, pentafluorobenzyl alcohol SPME, solid-phase microextraction TOPO, tri-n-octylphoshine oxide UASB, upflow anaerobic sludge blanket reactor. 

Dugay, J., Miege, C., and Hennion, M. C., Effect of the various parameters governing solid-phase microextraction for the trace-determination of pesticides in water, J. Chromatogr. A, 795, 27-42, 1998. 

FIGURE 3.10 Experimental setup of GC-DMS system. Chemical analysis is performed using gas chromatography differential mobility spectrometry (GC/DMS). Several user-defined parameters were selected factorial experiments (a) the RF voltage of the DMS sensor, (b) nitrogen carrier gas flow rate through the DMS, (c) solid phase microextraction (SPME) filter type, and (d) GC cooling profile. (From Molina et al.. Anal. Chim. Acta 368(2), 2008.)... 

Bias Y, Bieri S, Christen P, Veuthey J-L (2006) Evaluation of Solid-Phase Microextraction Desorption Parameters for Fast GC Analysis of Cocaine in Coca I-eaves. J Chromatogr Sci 44 (Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.) 394-398... 

The concept of the equilibrium sampler is analogous to that of the octanol-water equilibrium partition coefficient (fQ,w) used since the 1970s to predict the potential for persistent nonpolar contaminants to concentrate in aquatic organisms [71]. The use of equilibrium-t) e passive samplers in the aquatic environment depends on the development of a sampler-water partition coefficient (fCs ) defined as the ratio of sampler to water concentration of the compound of interest at thermod)mamic equilibrium. The other key parameter determining the utility of an equilibrium-type passive sampler is the time taken to reach an approximate equilibrium condition. A range of approaches applied in developing equilibrium-t)q)e passive samplers include polyethylene or silicon sheets of various volume to surface area ratio [72] and solid-phase microextraction techniques [73]. 

The critical parameters determining the instrumental hyphenation between solid-phase microextraction, gas chromatography and ICP were optimised. 

Amphetamines have also been extensively analyzed by GC-MS [2,32-36]. Recent work has focused on improvements in derivatization procedures [13], extraction techniques [1,33,35,36], and optimizing ionization parameters [14]. Solid-phase microextraction was utilized for headspace analysis of urine to determine both amphetamine and methamphetamine [32], In conjunction with the use of pentadeuterated methamphetamine as an internal standard, LODs were obtained as low as 0.1 llg/ml for both compounds monitored in the SIM mode and using isobutane CL This method was found to be 20 times more sensitive than traditional headspace analysis of urine without SPME extraction [32]. Even lower limits of detection were obtained utilizing derivatization of amphetamine and methamphetamine with propylchloroformate and LLE of the propylcarbamate derivatives from urine [13]. When deuterated amphetamine and methamphetamine were used as internal standards, the LODs were 25 ng/ml for both drugs the LOD improved to 5 ng/ml when Wpropylamphetamine was used as the internal standard. In this case, ions were formed via El and SIM was used (Fig. 4) [13]. This method was shown to be rugged and relatively free from potential interferences from other related drugs. 

Sampling Parameters for Dynamic Headspace Solid-Phase Microextraction Sampling... 

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