نتایج جستجو برای: spme solid
تعداد نتایج: 190012 فیلتر نتایج به سال:
Insect cuticular hydrocarbons (CHCs) play critical roles in reducing water loss and chemical communication. Species-specific CHC profiles have been used increasingly as an excellent character for species classification. However, considerably less is known about their potential for population delimitation within species. The aims of this study were to develop a solid-phase microextraction (SPME)...
A method for the determination of metolcarb and diethofencarb in apples and apple juice is developed using solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC). The experimental conditions of SPME, such as the kind of extraction fiber, extraction time, stirring rate, pH of the extracting solution, and desorption conditions are optimized. The SPME is perf...
A solid-phase microextraction (SPME) method has been developed for the quantification of polychlorinated biphenyls (PCBs) in water samples. Parameters such as sampling time, volume of water, volume of headspace, temperature, addition of salts, and agitation of the sample were studied. Because the time for reaching equilibrium between phases takes several hours or days, depending on the experime...
Solid phase microextraction (SPME) is a popular sampling technique whereby analytes are sorbed to a coated fiber and subsequently desorbed into an analytical instrument. In headspace SPME, analytes partition between the sample, the headspace above the sample, and the SPME fiber coating. In total vaporization SPME (TV-SPME), sample extracts are heated until both the solvent and analytes complete...
Since solid-phase and liquid-phase microextraction (SPME and LPME) were introduced, as effective solvent-free methods, many efforts have been made to improve their modes and applications. However, due to limitations with sensitivity and efficiency, researchers have focused on improving the performance of their basic primary modes. In this way, in recent years, different methods such as ultrason...
We developed a method for the evaluation of the partition coefficients (K(oc)) of hexachlorobenzene (HCB) and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) into humic substances (HSs) by using solid-phase microextraction (SPME). In the aqueous solution containing HCB or HpCDD and HS, the unbound species of HCB or HpCDD were accumulated on the SPME fiber. Subsequently, HCB or HpCDD on the SP...
Dimethylsulfoniopropionate (DMSP) and dimethyl sulphide (DMS) are compounds found mainly in marine phytoplankton and in some halophytic plants. DMS is a globally important biogenic volatile in regulating of global sulfur cycle and planetary albedo, whereas DMSP is involved in the maintenance of plant-environment homeostasis. Plants emit minute amounts of DMS compared to marine phytoplankton and...
Formation, occurrence and determination of volatile fatty acids in environmental and related samples
Volatile fatty acids (VFA) are short chain aliphatic monocarboxylic acids containing from 2 to 8 carbon atoms in a molecule. They are formed in the process of anaerobic biodegradation of larger organic molecules and therefore are commonly present in municipal wastewater, effluents of food industry, livestock farm wastewater, sewage sludge, landfill leachate, feces, urine, etc. and are emitted b...
Compound-specific carbon isotope ratio analysis is a promising tool to assess the origin and fate of organic contaminants in groundwater. The aim of this study was to develop and evaluate a reliable, fast method to determine carbon isotope ratios of chlorinated methanes, ethanes, and ethenes in aqueous samples. Direct solid-phase microextraction (dSPME) and headspace solid-phase microextraction...
Seedless triploid watermelons have increased in popularity since the early 1990s, and the demand for seedless fruit is on the rise. Sweetness and sugars are crucial breeding focuses for fruit quality. Volatiles also play an important role; yet, we found no literature for seedless varieties and no reports using solid-phase microextraction (SPME) in watermelon. The objective of this experiment wa...
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