نتایج جستجو برای: mercury determination
تعداد نتایج: 291013 فیلتر نتایج به سال:
Total mercury (Hg(T)) determination requires the addition of concentrated hydrochloric acid solution (≥10 mol L(-1) HCl) in relatively high amounts to preserve the samples and to prepare reagent solutions. A method for the preparation of concentrated HCl with Hg(T) concentration of lower than 5 ng L(-1) is described in this article. It is based on the well-known chemical reaction: 2 NH(4)Cl + H...
Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet occupies a Cassini state with obliquity of 2.11 +/- 0.1 arc minutes. The measurements show that the planet exhibits librations in longitude that are forced at the 88-day orbital period, as predicted by theory. The large amplitude of the oscillations, 35.8 +/- 2 arc seconds, together with the Mariner...
As a result of rapid industrialization several chemical forms of organic and inorganic mercury are constantly introduced to the environment and affect humans and animals directly. All forms of mercury have toxic effects; therefore accurate measurement of mercury is of prime importance especially in suspended particulate matter (SPM) collected through high volume sampler (HVS). In the quantifica...
The thermal stabilization characteristics of mercury species (inorganic and organic) in the presence of different chemical modifiers, including PdCl2 + ascorbic acid, (NH4)2PdCl6 + citric acid, (NH4)3RhCl6 + citric acid and a mixture of the last two salts, were investigated. The results indicate that PdCl2 + ascorbic acid can stabilize mercury species upto a temperature of 5008C whereas, with t...
The design and development of a microfabricated sensor for atmospheric mercury determination is described. The sensor is based on the technique of resistivity variation of thin gold film. Properties, advantages and drawback of two different substrates (glass and PCB) have been presented. Experiments have been carried out to test the linearity of the sensors in function of mercury adsorption. Th...
A method is presented for the rapid determination of total mercury in blood. The reagent used is alkaline sodium borohydride, and no digestion of the sample is needed. The detection limit and sensitivity are 1.15 and 1.59 ng of Hg, respectively. The method gives reproducible results (the CV ranged from 5.3 to 6.7% for low and high mercury blood samples, respectively), comparable to those obtain...
In the present study, a simple, rapid and sensitive method was developed for the determination of mercury concentrations in the muscle tissue of fish from the Brazilian Amazon using graphite furnace atomic absorption spectrometry (GFAAS) following acid mineralization of the samples in an ultrasonic cold water bath. Using copper nitrate as a chemical modifier in solution and sodium tungstate as ...
Mercury salts and tellurite are among the most toxic compounds for microorganisms on Earth. Bacterial mercury resistance is established mainly via mercury reduction by the mer operon system. However, specific mechanisms underlying tellurite resistance are unknown to date. To identify new mechanisms for tellurite detoxification we demonstrate that mercury resistance mechanisms can trigger cross-...
This study was conducted to determine the concentration of total mercury in the edible portion of 46 species of marine fish (n = 297) collected from selected major fish landing ports and wholesale markets throughout Peninsular Malaysia. Samples were collected in June to December 2009. Prior to analysis, the fish samples were processed which consisted of drying at 65 °C until a constant weight w...
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