9-(3-硝基苯基)-2,3,7-三羟基-4,5-二溴-6-荧光酮分光光度法测定微量钨

Spectrophotometric Determination of Microamounts of Tungsten (Ⅳ)with 9- (3-Nitrophenyl) -2, 3, 7-Trihydroxy-4, 5-Dibromo-6-Fluorone

研究了9-（3-硝基苯基）-2，3，7-三羟基-4，5-二溴-6-荧光酮（简称DBNPF）与钨的显色反应条件．在表面活性剂CTMAB存在下，HCI介质中，钨与DBNPF生成1：3（M：L）配合物，其最大吸收峰在550nm处，表观摩尔吸光系数ε＝1．1×105L·mol-1·cm-1，钨含量在0—9μg／25mL范围内符合比耳定律，大多数常见阳离子不干扰测定．本方法用于合成样品中微量钨的测定，结果满意．

The colour reaction of tungsten (Ⅳ ) with 9- (3-nitrophenyl) -2, 3, 7-trihydroxy-4, 5-dibromo-6-fluorone (DBNPF) in the presence of CTMAB has been investigated.Tungsten (Ⅳ) react rapidly with DBNPF to form 1：3 (M: L) complex with maximum absorption at 550nm, its molar absorptivity being 1.1 ×105L·mol-1·cm-1. Beer's law is obeyed for 0-9 μg of tungsten (Ⅳ) in 25mL. Most of other metal ions do not interfere with the determination. The method has been used to det ermifle tungsten in sample with satisfactory,results.