Analysis using microwave reactors

SFME is proposed as an environmentally friendly extraction method suitable for sample preparation before essential oil analysis. SEME is a very clean method which avoids the use of large quantities of water and voluminous extraction vessels, in contrast with HD. SEME could also be used to produce larger quantities of essential oils by using existing large-scale microwave extraction reactors [62]. These microwave reactors are suitable for the extraction of 10, 20, or 100 kg of fresh plant material per batch. These reactors could be easily modified and used for SFME extractions. 

Microwave irradiation was applied for in situ polymerization of PMMA/clay (ClOA) layered nanocomposites. The polymerizations were carried out using a microwave reactor at 70 °C with 200W of irradiation power. An intercalated/exfo-liated stmcture was observed by both XRD and transmission electron microscopy (TEM) analyses. Thermogravimetry analysis (TGA) of pure PMMA and PMMA/clay nanocomposites... 

The literature review of microwave-assisted or induced pyrolysis of plastics follows. In this section special attention is paid to the reactor configurations used, comparing them with the configurations found on more conventional pyrolysis equipment. The most important findings produced from this research are presented, including product yield, characteristics and composition. An analysis is presented to assess whether in any example there is evidence for nonthermal microwave effects promoting the pyrolytic reactions. 

The implementation of in-line ultrasound for sample preparation in flow analysis is analogous to microwave or UV irradiation. The coiled reactor (or a mini-chamber) is immersed in a water bath to which ultrasound is applied. As mechanical waves are involved, the inner walls of the tubing should be thin and flexible to avoid wave damping, which would decrease the efficiency of the ultrasound. Alternatively, an ultrasound probe can be placed near the ultrasound reactor [143]. The use of an... 

After microwave-assisted digestion of the sample with a mixture of nitric acid and hydrogen peroxide, during which equilibration with the isotopically enriched spikes added also took place, formic acid was used to convert the isotope-diluted elements into volatile compounds in a photo-reactor. In the case of iron and nickel, the corresponding volatile carbonyl compounds are most likely formed, whereas in the case of selenium, hydride compounds are obtained. A schematic representation of the UV-PVG-ICP-IDMS setup is shown in Figure 8.10. The good accuracy of results was demonstrated by the successful analysis of certified reference materials. Extremely low LODs of 0.18, 1.0, and 1.7 pgg were found for Ni, Fe, and Se, respectively, which are improvements of a factor of 30 for the two metals and 150 for Se compared with conventional pneumatic solution nebulization. 

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