催化氧化显色光度法测定粉煤灰中微量钒

Determination of trace vanadium in fly ash by catalytic oxidizing chromogenic spectrophotometry

在HAc -NaAc缓冲溶液 ( pH4 0 )中 ,痕量钒对KBrO3氧化原还型罗丹明B(RRDB)的显色反应有催化作用 ,催化程度与V 量线性相关。基于此 ,建立了一种光度法测定痕量V 的新方法。结果表明 ,在抗坏血酸存在下具有高灵敏的显色反应 ,表观摩尔吸光系数 (ε)为 3 8× 10 5 ,催化程度与V 量在 0～ 2 5 μg/2 5mL范围内符合比尔定律。本法用于测定粉煤灰中微量钒时 ,结果满意。

Trace vanadium catalyzes the chromogenic reaction of reduced rhodamine B oxidized by potassium bromate in the buffer solution of HAc-NaAc(pH 4 0),and its catalytic extent is linear with the concentration of V? Based on this study,a new spectrophotometric method for determining trace vanadium is developed The results show that the chromogenic reaction has highly sensitivity in the presence of ascorbic acid,the apparent molar absorptivity is 3 8×10 5L·mol -1 ·cm -1 ,and Beer’s law is obeyed for V? in the range of 0 0～2 5μg/25mL The method has been applied to the determination of trace vanadium in fly ash with satisfactory results