Dynamic MAE

Ericsson, M. and Colmsjo, A., Dynamic MAE coupled onhne with SPE determination of polycyclic aromatic hydrocarbons in sediment and soil, J. Chromatogr. A, 964, 11 -20, 2002. 

Figure 5 Manifold for dynamic MAE. 1, Solvent 2, pump 3, microwave oven 4, extraction chamber 5, temperature set-point controller 6, thermocouple 7, fluorescence detector 8, recording device 9, restrictor 10, extractor. (Reproduced with permission from Luque de Castro MD and Luque-Garcia JL (2002) Acceleration and Automation of Solid Sample Treatment, Elsevier.)...

HIA HIV-1 HOBt HSA ITC Lac MALDI-Tof MAES Man MD MS Hemagglutination inhibition assay A human immunodeficiency virus Hydroxybenzotriazole Human serum albumin Isothermal titration calorimetry Lactose (Gaipi-4Glc) Matrix-assisted laser desorption/ionization-lime of flight Multiangle light scattering Mannose Molecular dynamics Mass spectrometry... 

The fundamentals and practical use of MAE have been described in detail in several review articles (68-70) and books (18, 71, 72). The following text focuses on closed-vessel (pressurized) MAE, which permits extractions at elevated temperatures. A major difference of MAE compared to SEE and PLE, in addition to its unique heating performance, is that the commercially available MAE systems today operate in batch mode. The possibility of built-in clean-up is therefore difficult to perform and related to the design of the instrumentation. Both automated SEE and PLE are most commonly used in a dynamic or semidynamic mode, which simplifies the development of combined extraction/clean-up strategies. 

When 14 units of y, corresponding to a 0.7 mM pulse, are added at various phases of an oscillation cycle (fig. 2.18), the maximum effect of the perturbation is to induce a delay of more than 1 min when the addition occurs near the minimum of y, while the perturbation remains almost without effect near the maximum. This differential effect can be explained by the dynamic behaviour of the enzyme in the course of oscillations when the product reaches its maximum, the enz)mae is mainly in the R state, which is the most active, given that the reaction product is a positive effector and favours the transition from the T to the R state of the enzyme. Adding product at that phase of the oscillations has practically no effect, because the enzyme is already predominantly in its most active state. 

Weckx, S., Van derMenlen, R., Maes, D. S. I., Huys, G., Vandamme, P. D. V.L. (2010). Lactic acid bacteria commnnity dynamics and metabolite production of rye sourdough fermentations share characteristics of wheat and spelt sourdough fermentations. Food Microbiology, 27, 1000-1008. 

Figure 3 Experimental design for continuous MAE, liquid-liquid extraction, sorption/cleanup of phenol compounds in soil samples. IV, injection valve PS, membrane phase separator o.p. and a.p., organic and aqueous phases W, waste. (Reproduced with permission from Ericsson M and Colmsjo A (2000) Dynamic microwave-assisted extraction. Journal of Chromatography 877 141 Elsevier.)...

The dynamic high-pressure MAE system described previously also allows the extraction to be coupled to a subsequent stage by connecting the extractor outlet to the unit concerned. Figure 5 illustrates one possible coupling connecting the extractor to a fluori-metric detector allows the kinetics of the extraction of PAHs from sediments to be monitored. 

Neither MAE nor ASE is currently in a configuration that would readily lead to the automation of sample preparation. Supercritical fluid extraction can be used as online system that can then be connected to the chromatographic and detection systems. Connected online with the GC/MS, SFE was successfully used for the determination of PAHs in marine sediments. Using either CO2 alone or modified with toluene or MeOH in the extraction, the PAHs were cryofocused in the accumulation cell of the GC and then directly chromatographed. For the study of PAHs in marine sediments, a new extraction technique, which consists of the combination of ASE (dynamic and static mode) and SFE (dynamic mode), was developed, with an extraction time longer than in ASE but shorter than in SFE, and... 

H. Mae, Dynamic tensile behavior and light transmittance of cyclo-olefine polymer/clay composites, Zairyo/Joumal of the Society of Materials Science, Japan 58 (11) (2009) 895-902. 

Jans H, Liu X, Huo Q, Austin L, Maes G (2009) Dynamic light scattering as a powerful tool fcff gold nanoparticle bioconjugation and biomolecular binding studies. Anal Chem 81 9425-9432... 

The predicted hydraulic parameters were applied in Hydrus-ID to simulate soil moisture dynamics in 0-20 cm and 20-40 cm depth intervals. Table 2 shows that statistical results of MAE and... 

LLE, liquid-liquid extraction MAE, microwave-assisted extraction SEE, solid-phase extraction SPME, solid-phase microextraction LPME, liquid-phase microextraction SOME, single-drop microextraction D-LLLME, dynamic liquid-liquid-liquid microextraction SEE, supercritical fluid extraction MIP, molecularly imprinted polymers sorbent SPMD, device for semipermeable membrane extraction PDMS, polydimethylsiloxane coated fiber PA, polyacrylate coated fiber CW-DMS, Carbowax-divinylbenzene fiber PDMS-DVB, polydimethylsiloxane divinylbenzene fiber CAR-PDMS, Carboxen-polydimethylsiloxane coated fiber DVB-CAR-PDMS, divinylbenzene Carboxen-polydimethylsiloxane coated fiber CW-TPR, Carbowax-template resin HS-SPME, headspace solid-phase microextraction MA-HS-SPME, microwave-assisted headspace-solid-phase microextraction HEM, porous hollow fiber membrane PEl-PPP, polydydroxylated polyparaphenylene. 

The mode of extraction for PAHs is highly dependent on the matrix. For solid-based matrices such as food samples, sediments, soil, marine organisms, etc. extraction methods such as Soxhlet extraction with nonpolar solvent [35 6], hollow fiber membrane solvent microextraction (HFMSME) [10], pressimzed hquid extraction (PLE) [37,38], sonication extraction [3], microwave-assisted extraction (MAE) [3], supercritical fluid extraction, (SEE) [39], accelerated solvent extraction (ASE) [40], cold extraction [41], soxtec extraction [42], microwave-assisted alkaline saponification (MAAS) [43], dynamic microwave-assisted extraction (DMAE) [44], add-induced cloud point extraction (ACPE) [45], methanolic saponification extraction (MSE) [7], etc. are employed. Of all these, Soxhlet extraction is the most common for solid samples and has achieved excellent extraction with high-level recovery but its setback is the high consmnption of solvent and time associated with it. 

Dynamic versus Static SFE Accelerated Solvent Extraction (ASE) Microwave-Assisted Extraction (MAE) Membrane-Based Extractions Pyrolysis Automation Derivatization Thermal Desorption... 

Dynamic Aspects of Fatty Acid Vesicles pH-induced Vesicle-Micelle Transition and Dilution-induced Formation of Giant Vesicles Goto, Suzuki, Yoshioka, Goto, Mae, Yamazaki and Walde) 6 261... 

Our first experience with levels involved the 4/ states of Pr + and the levels of 11" + [86]. Excellent agreement with experiment was obtained, with an MAE of 222 cm for the Pr + levels and 114 cm for 11 +. The error for Pr + was four times smaller than that of the MCDF calculation [87], demonstrating the more comprehensive inclusion of dynamic correlation by CC. More recently, a larger basis set was employed, extending the analysis to include the excited states of U + and the 5/, Sfls, and Sfbd states of U +, which are important in interpreting the electronic spectrum of the neutral UO2 molecule [25]. Results are presented and compared with experiment [88] and other calculations in Table 2.13. It should be noted that we use one set of canonical SCF spinors for all states in... 

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