在pH5.0的乙酸钠缓冲液中,铌-N-BPHA络合物可产生灵敏的极谱催化波。峰电位在-1.05伏特。峰高与浓度在0.004～0.4微克·毫升~(-1)之间呈线性关系。底液中加入DCTA络合剂,可消除一定量的铁、铝、钛等常见共存离子的干扰,可不经分离直接测定矿石中0.001%以上的五氧化二铌。 The niobium-N-BPHA complex produces sensitive polarographic catalytic waves in sodium acetate buffer at pH 5.0. The peak potential is -1.05 volts. There was a linear relationship between the peak height and the concentration of 0.004-0.4 μg · mL -1. The addition of DCTA complexing agent in the bottom liquid can eliminate the interference of a certain amount of common ions such as iron, aluminum and titanium, and can directly measure 0.001% or more of niobium pentoxide in the ore without separation.