نتایج جستجو برای: 99 standard method with hexane and acetone solvents
تعداد نتایج: 18593444 فیلتر نتایج به سال:
A solid-phase extraction (SPE) method for sample clean-up and preconcentration followed by reversed-phase high-performance liquid chromatography (RP-HPLC) with uv detection is reported for determination of polycyclic aromatic hydrocarbons (PAHs) in the caspian seawater. A good resolution was obtained using acetonitrile:water (40:60) as mobile-phase for separation of these compounds. The eff...
BACKGROUND: Botanicals insecticides has remained the major weapons amongst tropical zones farmers to combat hexapods infestation of stored cowpea seeds in lieu of expensive synthetic chemical insecticides that have toxic effects on our environment. OBJECTIVES: Deterrence of cowpea bruchid oviposition and emergence on seeds treated with Cheese wood, Alstoni...
the purpose of this study was to investigate the relationship between teachers’ class management practices with students’ self- regulated learning and academic self-efficacy. in this study relating to the management class, three dimensions, (training management, people management and behavior management) and three style (interventionist, interactionist and non-interventionist) was considered. r...
for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...
The effects of extraction solvents (hexane, ethyl-acetate, acetone, ethanol, methanol, and water) on the content of phytochemicals including total polyphenols, flavonoids and condensed tannins, as well as antioxidant activities of walnut green husk were investigated. The results showed that extraction solvents significantly affected phytochemicals content and antioxidant activities of walnut gr...
The aim of the present study is to focus on the cytotoxicity and antimicrobial activities from Annona squamosa plant seed extracts. The plant A. squamosa seed was extracted with various solvents like chloroform, methanol, hexane, petroleum ether and acetone. The antimicrobial activities of all these extracts were determined by disc diffusion method against Pseudomonas aeruginosa, Proteius vulga...
abstract sensitive and precise voltammetric methods for the determination of trace amounts of furaldehydes, mainly as furfural (f) and 5-hydroxymethyl-2-furaldehyde (hmf), in waste waters and other matrices is described. determination of total furaldehyde at < ?g g-1 levels in alkaline buffered aqueous media was individually investigated. by the use of ordinary swv and adsorptive square wave ...
in new management approaches, in the organizations with inflexible structure, existing of red tapes and interruptions caused by limitations and also non-compliance with environmental changes, create demotivation among staff. with regard to the influence of job motivational potential and its relationship to the type of organizational structure( enabling and dissuasive), the goal of this research...
The present study investigates antibacterial activity of tobacco extracts from Nicotiana tabacum at different concentrations in different polar solvents. Six different extracts were prepared, using 5 different polar solvents viz., Ethanol, Ethyl acetate, n-Hexane, Acetone, Butanol and water. Four different concentrations (6, 12, 18 and 24 mg of sample disc) of each extract were subjected for pr...
Refining of industrial lignin to produce homogeneous fractions is essential for high-value applications. However, the understanding key interactions between a variety solvents with polymer still uncertain. In this work, single-step fractionation hardwood kraft (HKL) using organic different polarities – ethanol, acetone, diethyl ether and hexane was investigated by combining an experimental theo...
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