نتایج جستجو برای: ultrasonic assisted microextraction
تعداد نتایج: 159984 فیلتر نتایج به سال:
The volatile components of Citrus aurantium L. flowers were characterized by GC-MS with two different extraction techniques, hydrodistillation (HD) and ultrasonic-assisted headspace solid phase microextraction (UA-HS-SPME). In the SPME method, the volatile components of the samples, irradiated by ultrasonic radiation, were collected on a polydimethyl siloxane (PDMS) commercial fiber as...
Kleinová J., Klejdus B. (2014): Determination of volatiles in beer using solid-phase microextraction in combination with gas chromatography/mass spectrometry. Czech J: Food Sci., 32: 241–248. Headspace solid phase microextraction and purge and trap analysis were used for the determination of volatiles in beer. These methods were compared with the analysis of unconcentrated gas phase and liquid ...
In this investigation, the material removal rate, tool wear rate and surface integrity obtained by EDM, ultrasonic vibrations assisted EDM and magnetic field assisted EDM were studied and compared with together to show the quality of the effects of applying each of ultrasonic vibrations to tool and magnetic field around gap distance of EDM process on material removal rate, tool wear rate, and s...
The analytical use of ultrasound-generated emulsations has recently found a growing interest to improve efficiency in liquid-liquid microextraction since they increase the mass transfer between the two immiscible phases implied and leads to emulsification. Thus, dispersed droplets can act as efficient liquid-liquid microextraction in continuous phase, and later they can be readily separated by ...
Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME) combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides). The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE) with two s...
Background & Aim:Medicinal plants are rich sources of substances with nutraceutical and health benefits. Valeriana officinalis L. (Valerianaceae) is a known medicinal plant used in traditional medicine throughout the world. The present study aimed to evaluate the efficiencies of three methods for antioxidant extraction from Valeriana officinalis</...
nowadays the surface texturing has been widely recognized as a usable capability to improve the tribological systems. in this paper, ultrasonic assisted turning (uat) isperformed to create the micro textures on the flat faces. micro surface texturing ismade on the al7075-t6 by the uat in the face turning process. then, the influences of cutting speed feed, vibration direction and vibration ampl...
One of the great challenges in the processing of materials using Equal Channel Angular Pressing (ECAP) is the high forming forces required to produce large shear deformation in the material. Researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. Recently, ultrasonic vibrations are successfully implemented into the ECAP proce...
A new, rapid and sensitive microextraction technique named vortex-assisted liquid-liquid-liquid microextraction (VALLLME) is proposed. The complete extraction process involves two steps. First, a vortex-assisted liquid-liquid microextraction (VALLME) procedure was used to extract the analytes from a relatively large volume of sample (donor phase) to a small volume of organic solvent (intermedia...
one of the great challenges in the processing of materials using equal channel angular pressing (ecap) is the high forming forces required to produce large shear deformation in the material. researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. recently, ultrasonic vibrations are successfully implemented into the ecap proce...
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