【摘要】 本文报告于0.4N硫酸介质中生成硅钼杂多酸,然后提高酸度至3.96N硫酸介质,借硅钼杂多酸被赤霉素还原成硅钼杂多蓝的显色反应作分光光度测定硅.磷（V）25倍于硅时,砷（V）20倍于硅时无干扰.蓝色化合物可稳定一天,其摩尔吸光系数和桑德尔灵敏度分别为3.51×10⁴摩尔.升^-1·厘米^-1和0.0008微克/厘米².本法曾用于钢铁中硅的测定,方法灵敏,选择性好,并获得满意的分析结果.更多还原

【Abstract】 Gibberellin which has been investigated as a new reducing agent in the molybdenum blue method for the spectrophotometric determination of silicon in iron and steel is reported in this paper. In 3.96 N sulfuric acid medium, molybdosilicic acid is quantitatively reduced by gibberellin with heating for 3 minutes in a boiling water bath.The blue compound which is stable for at least one day has a maximuin absorption at 810 nm. The molar absorptivity and Sandell’s sensitivity of the blue compound are 3.51×10⁴ L·mole^-1-1·cm^-1 and 0.0008 μg/cm², respectively. Beer’s law is obeyed in the concentration range 0～20 μg Si/25mL（using 1 cm cell）and 0-10μg Si/25 mL （using 3 cm cell） . Phosphorus in 25-fold excess and arsenic in 20-fold excess do not interfere with the determination of silicon.The method has been successfully applied to the determination of silicon in iron and steel with satisfactory results.The recommended procedure has many advantages over other reducing agents and is simple, sensitive,selective, accurate and reproducible.更多还原