Single-molecule force spectroscopy with an atomic force microscope has been widely used to study inter- and intramolecular interactions. To obtain data consistent with single molecular events, a well-defined method is critical to limit the number of molecules at the apex of an AFM probe to one or to a few. In this paper, we demonstrate an easy method for single-molecule probe modification by us...

anzali international wetland is one of the most valuable water resources as registered in ramsar convention with an extent of about 150 km2 in the south caspian sea. this wetland, not only has ecological and biological importance for migratory birds and rare fish species, but also is used for farms to discharge into the caspian sea through this wetland. therefore its pollution control is very i...

a simple, highly sensitive, accurate and selective method for determination of trace amounts of cu2+ in water samples .in this paper, chitosan was used to encapsulate nano-fe3o4 and produce a nano-fe3o4-chitosan sorbent based new sorbent was prepared. this was treated with ethylenediamine (ed) in another solvent-free procedure for the formation of a novel nano-fe3o4-chitosan-ed.flame atomic abs...

a simple and rapid microextraction procedure based on dispersive liquid-liquid microextraction (dllme) was developed for determination and speciation of trace amounts of chromium (cr) by flame atomic absorption spectrometry (faas). in the proposed approach, chloroform and methanol were used as extraction and dispersive solvents. a new schiff's base ligand, bis(2-methoxy benzaldehyde) ethylene d...

heavy metals are highly poisonous in the environment, even in small quantities, and endanger certain species and all live beings. current methods of removing heavy metals from aqueous media include chemical sequestration, ion exchange, surface absorption, membrane processes, oxidation and revival procedures which have high investment and exploitation costs. hence, it is significantly necessary ...

pb and cd in water samples were determined by cloud point extraction (cpe) with sodiumdiethyldithiocarbamate (ddtc) as the chelating agent and octylphenoxypolyethanl (triton x-114) asthe surfactant prior to flame atomic absorption spectrometry (faas) determination. the main factorsof affecting the extraction and detection processes were optimized. the preconcentration of 10 ml ofstandard soluti...

this paper investigates host condition factor, parasite interaction and metal accumulation in tilapia guineesis and host-parasite system in iddo area of lagos lagoon, nigeria. eighty specimens of t. guineensis from the lagoon were caught and dissected for intestinal helminth parasites. condition factors of all individuals were determined. median condition (k<2.62 and k>2.62) were used in groupi...

distribution and mobility of nine mineral elements (k, ca, na, mg, fe, zn, cu, se, and cr) in cultured gentiana rigescens and its root zone soil were determined by atomic absorption spectroscopy. g. rigescens materials were planted under tea and white papaya trees in yun county and yongde of lincang area in yunnan province of china. the results showed that g. rigescens and its soil were high in...

background: the objective of this work was developing a simple and stable time-based on-line setup for assessing the potential of mercury (hg) vapor adsorption of the commercial sorbents used in air sampling and control operation followed by cold vapor atomic absorption spectrometry (cvaas). methods: a special designed separation chamber was used where reduction of the injected hg (ii) solution...

background soil pollution due to toxic metals released by industrial activities such as cement production is a serious problem from the standpoints of the environment and public health, because they tend to persist, circulating indefinitely and, eventually, accumulating throughout the food chain. objectives this paper presents the results of the first research study into the distribution of cad...