نتایج جستجو برای: extractants
تعداد نتایج: 538 فیلتر نتایج به سال:
A simple and rapid procedure for the determination of plutonium isotopes in the environment is presented. The procedure combines alpha spectrometry, solvent extraction and liquid scintillation measurements to ensure that both alpha- and beta-emitting isotopes are determined. Of five tested extractants, bis-(2-ethylhexyl) phosphoric acid was found to be the best choice. The procedure was applied...
Palladium-catalyzed cross-coupling of (di)chloropyrazines with phosphorus pronucleophiles in the presence of a base gave the phosphorylated pyrazines in 81-95% yields. Based on this methodology a series of appropriately functionalized pyrazines was prepared as potential extractants of trivalent cations from highly acidic nuclear waste. A few hydrophilic derivatives exhibited a very good selecti...
THE PURPOSE. In order to control the technical condition of oil-filled electrical equipment, a number new analytical methods have recently been created determine ultra-low concentrations impurity compounds in transformer oil. An analysis literature data showed that at this stage procedure significant errors may occur worsen quality and some cases make its results meaningless. The published prac...
Transformer oil is widely used in power oil-filled electrical equipment, which an insulating and diagnostic medium. During the operation of transformers, its operational dielectric properties deteriorate. To increase operating time transformer oil, it inhibited by antioxidant additive, most often as ionol concentration must be constantly monitored. This control carried out chromatographic metho...
High concentrations of arsenic have been detected in soils and underlying groundwater of some South Florida golf courses, indicating the possible impact of the application of arsenic-containing herbicides. The mobility of arsenic in the soils from selected golf courses was studied using a simple two-step sequential extraction procedure. Sodium nitrate (0.1 M), potassium dihydrogen phosphate (0....
This study was conducted to determine the effect of 3 extractants on K release from biotite, phlogopite and muscovite. The minerals were grouped to <60 and 60-100 µm size classes. Particles CEC were saturated with calcium. Sequential extraction up to 30 times was carried out using 0.01M HCl, 1M NH4OAc and 0.05M BaCl2 solutions and cumulative concentration of K was calculated for each extractant...
Two extractants, N,N′-((octylazanediyl)bis(ethane-2,1-diyl))dioctanamide (LI) and N,N′-((octylazanediyl)bis(ethane-2,1-diyl))di-2-methylheptanamide (LII), have been synthesised in two steps starting from diethylenetriamine involving a peptide coupling step. The efficiency selectivity of the extractants dodecane/octanol (95/5 v/v) toward extraction uranium sulfate media investigated showing that...
Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that ...
The abilities of various extractants to recover four arsenic species [As(iii), As(v), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA)] from soils spiked with 20 micro g g(-1) As were investigated. The extractants were water, buffer solutions (citrate and ammonium dihydrogen phosphate), acidic solutions (phosphoric acid and acetic acid), a basic solution (sodium hydroxide) and house...
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