نتایج جستجو برای: sequential extraction methods

تعداد نتایج: 2068775  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1391

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...

Journal: :international journal of environmental research 2015
m. salmanzadeh m. saeedi l.y. li gh. nabi-bidhendi

fifty street dust samples were collected from southern and eastern parts of tehran, the capitalof iran. samples were collected during summer under dry and stable weather conditions. total concentrationsof copper (cu), cadmium (cd), lead (pb), chromium (cr), nickel (ni), zinc (zn), iron (fe), manganese (mn)and lithium (li) were determined. ten samples were then selected for characterization, met...

Journal: :آب و خاک 0
هانیه سپهوند اکبر فرقانی

abstract zinc (zn) is an essential plant nutrient. knowledge about distribution of zn between its different chemical forms is useful in understanding the chemistry of this element in soil and also in development of soil testing procedures. the present study was conducted to obtain such information about distribution of zinc forms in 20 soil samples of lorestan province by the use of a sequentia...

Journal: :ecopersia 2015
mohammad sayadi mohammad rezaei omolbanin rashki ghaleno khosro afsari nayerh poormollaeib

thechah nimeh reservoirs of sistan is as one of the main water sources of zabol city used for drinking, agriculture, industry and livestock purposes. this study aimed to determine the contribution of the natural and concentration factors of heavy metals such as cd, pb and cu in sediment of chah nimeh of sistan. the concentrations of heavy metals in surface sediments were studied in six stations...

Journal: :international journal of environmental research 0
e.o. okuku kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya, soil and water management division, faculty of bioscience engineering, katholieke universiteit leuven, kasteelpark arenberg 20, b-3001 heverlee, belgium h.k. peter tanzania fisheries research institute, p.o. box 9750, dar es salaam, tanzania

the study aimed to come up with a list of specific macroalgae species, which could be used to biomonitor specific metal elements in the coastal waters of east africa. water extraction, edta, aqua regia extraction and optimized bcr 3-step sequential extracts were used to mimic bioavailable metals under various environmental conditions. the results indicated that ulva lactuca could be used as a b...

Journal: :آب و خاک 0
سعید باقریفام امیر لکزیان سیدجواد احمدی بهرام سلیمی آخرین فرید اصغری زاده

abstract uranium as a natural radioactive heavy metal widely disperses throughout the earth's crust. in many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. uranium through the plant uptake can enter the chain. the degree of speciation of radio nuclides in soils in areas with differing...

پایان نامه :0 1370

all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

Journal: :international journal of environmental research 2011
e.o. okuku h.k. peter

the study aimed to come up with a list of specific macroalgae species, which could be used to biomonitor specific metal elements in the coastal waters of east africa. water extraction, edta, aqua regia extraction and optimized bcr 3-step sequential extracts were used to mimic bioavailable metals under various environmental conditions. the results indicated that ulva lactuca could be used as a ...

Journal: :iranian journal of science and technology (sciences) 2012
m. a. ashrafi

the chemical speciation of heavy metals (arsenic, chromium, copper, lead, zinc and tin) in the sediments offormer tin mining catchment bestari jaya, peninsular malaysia was determined by using the latest version of the community bureau of reference, usually called the bcr 3-step sequential extraction procedure. furthermore, a fourth step was introduced for digestion and analysis of the residue....

Journal: :int. journal of mining & geo-engineering 2013
saeed yousefi faramarz doulati ardejani mansour ziaii esmat esmaeil zadeh arezoo abedi

knowledge of the probable origin and behaviour of arsenic certainly gives valuable insights into the potential for transfer in the environment and of the risks involved in mining sites. sequential extraction analyses are common experiments often used to study the origin and behaviour of potentially toxic elements. the method, however, presents some deficiencies, including labor-intensive proced...

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