نتایج جستجو برای: ultrasound assisted microextraction
تعداد نتایج: 237824 فیلتر نتایج به سال:
Drying is one of the widely used methods of food preservation and it is a sensitive food processing operation due to undesirable changes in the quality of dried product. In this study the effect of osmotic dyhedration and ultrasound pretreatment prior to convective drying on quality properties of apple slices was investigated. Apple slices were pretreated by osmotic dehydration in two concentra...
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...
A new, rapid and highly sensitive and rapid method was proposed for the simultaneous determination trace levels of vitamin C and folic acid in the human urine samples. The inûuence affecting factors on the UA-DLLME such as type and volume of the dispersive and extraction solvent, pH, ionic strength and temperature of sample solution, sonication condition investigated and optimized. Under the op...
A novel, rapid and efficient manual shaking and ultrasound-assisted surfactant-enhanced emulsification microextraction (M-UASEME) combined with gas chromatography-flame photometric detection (GC-FPD) was developed for the extraction and determination of eight organophosphorus pesticides (OPPs) in tap water and honey samples. The main parameters that affected the extraction efficiency were inves...
In the present work, a new ligandless-ultrasound-assisted emulsification microextraction (LL-USAEME) method was developed for preconcentration trace amounts of nickel as a prior step to its determination by flame atomic absorption spectrometry. Some factors influencing the extraction efficiency of nickel and its subsequent determination were studied and optimized, such as type and volume of the...
a simple and green chemical procedure was reported for the synthesis of dihydropyrimidinones from various aldehydes, ethyl acetoacetate and urea or thiourea using holmium chloride as catalyst. the reactions were performed under solvent free conditions with ultrasound irradiation as the energy source. the advantages of this protocol include the excellent yield, operational simplicity, short tim...
phenolic compounds, especially those of plant origin, constitute an essential part of the human diet, and are of considerable interest due to their antioxidant properties. in this study, ultrasound-assisted extraction (uae), microwave-assisted extraction (mae), as well as maceration extraction (me) methods were applied for phenolic compounds’ extraction from pistachio green hull. response surfa...
In the present study, an ultrasound-assisted emulsification microextraction based on solidification floating organic drop method is described for preconcentration of trace amounts of Mn (II). 2-(5-Bromo-2-pyridylazo)-5 diethylaminophenol was added to a solution of Mn(+2) at ph = 10.0. After this, 1-undecanol was added to the solution as an extraction solvent, and solution was stirred. Several f...
Abstract As the world population continues to grow, so does pollution of water resources. It is, therefore, important identify ways reducing as part our effort significantly increase supply clean and safer water. In this study, efficiency ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) a fast, economical, simple method for extraction malachite green (MG) rhodamine B (RB)...
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