[Study on selenium and polysaccharide distribution in different time ginkgo leaf].

Selenium and selenium speciation in gingko leaf is different in different vegetal period. Each kind of dissolved selenium varies with the seasons. The total selenium content in gingko leaf picked in different season was studied and the various dissolved selenium content distribution was discussed. The selenium content in July, September and after the first frost is respectively 1.875, 2.136 and 0.815 mg x kg(-1). The selenium exists in gingko leaf primarily as a water-soluble speciation. According to the experiment, the thick polysaccharide content in the gingko leaf is in the order: July < September < November. The thick polysaccharide in July is the sepia solid powder 25.64 g x kg(-1) and purity is 20.20%; In September the condition is the faint yellow solid powder 31.60 g x kg(-1) and purity is 8.68%; In November is in turn the cream color solid powder 83.57 g x kg(-1), and purity is 17.60%. Their deproteinised solution have no absorption peaks at 260 and 280 nm by UV-Vis, which further demonstrates that the solid powder is exactly the thick polysaccharide by IR. Determination of trace element content in the gingko leaf and the thick polysaccharide was carried out by ICP-MS, and the trace element content also changes along with the seasons.

[Determination of micro amount of tellurium (IV) in crude selenium sample by kinetic-specatrophotometry].

A new indicator reaction based on the interaction of sodium sulfide reducing properties with methylene blue in cetyltrimethylammonium bromide pH 3.8 acetic acid buffer solution was put forward to determine micro amount of tellurium. The effect of concentration of reaction substances, acidity, interfering ions etc. on the analytical results was studied. The apparent activation energy is 68.94 kJ x mol(-1) and the constant of reaction rate is 1.63 x 10(-2) s(-1). Beer's law is obeyed for tellurium in the range of 20-220 ng x mL(-1). The regression equation is y = 0.003 8x + 0.219 1 and the correlation coefficient is r = 0.999 5. The limit of detection for Te is 3.04 ng x mL(-1). The method was applied to the determination of Te in crude selenium sample, and the relative standard deviation is 3.1% (n = 7). The recovery was between 98.4% and 100.4%.

[Separation and determination of selenium polysaccharide in enriched-Se cordyceps militaris].

In the present paper, the water soluble selenium polysaccharide was extracted, and isolated and purified preliminarily. The traditional method was used to extract selenium polysaccharide, which was extracted by water and sank by ethanol. The work also focused on the determination of the experiment conditions, optimizing the experiment conditions such as proportion of extract solution, extract temperature, extract times, proportion of ethanol, and standing time. The recovery of selenium polysaccharide under these conditions is 5.76%. Polysaccharide content in the powder is 46.6%, and selenium content is 92.3 mg x kg(-1).

[Determination of active species of heavy metals in sewage sludge by ICP-MS].

Sewage sludge samples for the research from the sewage disposal plants of the north, Mantang River and Xiannu River in Shenyang were extracted and separated by H2O, HAc and organic solvents of different polarities. The active species of Cd, Pb, Cu, Zn and Cr existing in the sewage sludge were determined by ICP-MS, and the regularity and influential factors were studied under the alternation of environmental conditions. The results showed that the content of acid-soluble heavy metals was more than that of water-soluble ones, and both had coincident regularity under the alternation of time and temperature; the content of the organic solvents was positively correlated to the solvent polarity. The acid-soluble heavy metals were more active during the course of transforming, and the activity sequence of heavy metals in the same species was: water-soluble Zn>Cu>Cd> Pb>Cr, acid-soluble Cd>Cr>Cu>Zn>Pb, and organic-soluble Pb>Cd>Cr>Cu>Zn.