Selenium concentration in hair are sorted out into three classes, i.e. low (<110 ppb), medium (110-520 ppb) and high (>520 ppb) according to the principle of multiple normal distribution and a map of classificat...Selenium concentration in hair are sorted out into three classes, i.e. low (<110 ppb), medium (110-520 ppb) and high (>520 ppb) according to the principle of multiple normal distribution and a map of classification of selenium concentration in hair from children and youngsters in China has been drawn. Selenium insufficiency in relation to Keshan disease and Kashin-Beck's disease is expounded. Geographical differentiation of hair selenium concentrations and its causes are explained.展开更多
A new catalytic kinetic method for determining trace selenium(Ⅳ) was described.Se(Ⅳ) can catalyze the discolouring of 2 (5 Bromo 2 Pyridylazo) 5 diethylaminophenol(5 Br PADAP) by potassium chlorate in hydrochloric a...A new catalytic kinetic method for determining trace selenium(Ⅳ) was described.Se(Ⅳ) can catalyze the discolouring of 2 (5 Bromo 2 Pyridylazo) 5 diethylaminophenol(5 Br PADAP) by potassium chlorate in hydrochloric acid medium.The detection limit for Se(Ⅳ) is 5.7×10 -5 μg/ml.The linear range of determination is 0~ 0.4μg/25ml Se(Ⅳ).Satisfactory results may be obtained by direct determination of trace Se(Ⅳ) in human hair.展开更多
文摘Selenium concentration in hair are sorted out into three classes, i.e. low (<110 ppb), medium (110-520 ppb) and high (>520 ppb) according to the principle of multiple normal distribution and a map of classification of selenium concentration in hair from children and youngsters in China has been drawn. Selenium insufficiency in relation to Keshan disease and Kashin-Beck's disease is expounded. Geographical differentiation of hair selenium concentrations and its causes are explained.
文摘A new catalytic kinetic method for determining trace selenium(Ⅳ) was described.Se(Ⅳ) can catalyze the discolouring of 2 (5 Bromo 2 Pyridylazo) 5 diethylaminophenol(5 Br PADAP) by potassium chlorate in hydrochloric acid medium.The detection limit for Se(Ⅳ) is 5.7×10 -5 μg/ml.The linear range of determination is 0~ 0.4μg/25ml Se(Ⅳ).Satisfactory results may be obtained by direct determination of trace Se(Ⅳ) in human hair.