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 ...

oxidative addition reactions of 1,4-diiodo-butane and 1,3-diiodo-propane with [ptme2(ph2phen)]; in which ph2phen=4,7-diphenyl-1,10-phenanthroline, were studied in different solvents such as acetone and benzene.oxidative addition reaction of [pt me2(ph2phen)] with i(ch2)4i and i(ch2)3i produced the [pt me2i(ch2)4(ph2phen)i] (1a) and [pt me2i(ch2)3(ph2phen)i] (1b).all the platinum (iv) products w...

in this work, a novel and fast method for direct analysis of volatile compounds (davc) of medicinal plants has been developed by holding a filament from different parts of a plant in the gc injection port. the extraction and analysis of volatile components of a small amount of plant were carried out in one-step without any sample preparation. after optimization of temperature, extraction time a...

since the 1960s the age effects on learning both first and second language have been explored by many linguists and applied linguists (e.g lennerberg, 1967; schachter, 1996; long, 1990) and the existence of critical period for language acquisition was found to be a common ground of all these studies. in spite of some common findings, some issues about the impacts of age on acquiring a second or...

according to webster and wind (1972) and anderson et al (1987), “organizational buying is a complex process and involves many people from different functional areas, multiple goals and potentially conflicting decision criteria. moreover, the customers of today are also more knowledgeable and selective when making their purchasing decisions. since a key to organizational survival is the retentio...

the purpose of this study was to investigate iranian efl learners’ beliefs about the role of rote learning (rl) in vocabulary learning strategies; besides, the study examined if english proficiency would influence learners’ vocabulary learning strategy use. this study addresses the need for a clear understanding of the role of rl in efl vocabulary learning by looking at iranian efl learners’ ow...

the present research was conducted to accomplish two purposes. firstly, it aimed to explore and describe schematic structure or what halliday and hassan (1989, p.64) have called “generic structure potential” (gsp) of american english, iranian persian and iranian english newspaper editorials within systemic functional linguistics. secondly, a quantitative cross-comparison was made to investigate...

within communicative, interactive, and learner-centered framework of language teaching and learning, students need to learn four skills of listening, speaking, reading, and writing for their educational success. but of all the language skills, reading enjoys a paramount significance in so many second or foreign language academic contexts. in spite of its importance, language learners still have...

fluorescence chemical sensors for the highly sensitive and selective determination of pb2+ , hg2+, co2+ and fe3+ ions in aqueous solutions are described. the ion sensing system was prepared by incorporating lipophilic ligand (l) as a neutral ion-selective fluoroionophore in the plasticized pvc membrane containing sodium tetraphenylborate or potasium tetrakis (p-chlorophenyl) borate as a liphoph...

abstract amino acids are building blocks of proteins, and play a vital role in living beings existence and their functionality. the interaction of these compounds with metal ions is of great importance to biochemists, and chemists, because their functions can be utilized as a model in understanding enzymes mechanism for transport of metal ions to tissues. among twenty essential amino acids w...