研究了5-(4-二乙氨基苯偶氮)-8-羟基喹啉(DEPAQ)与钒(Ⅴ)的显色反应。结果表明,在TritonX-100存在下,pH5.0～7.0的缓冲介质中,钒(Ⅴ)与DEPAQ形成1:2的红色络合物,最大吸收波长为525nm,表观摩尔吸光系数ε=4.74×10~4L·mol~(-1)·cm~(-1)。钒含量在0～30μg/25ml范围内符合比尔定律。在CyDTA和氟化钠存在下,用于钢铁样品中钒的测定,结果令人满意。 The color reaction of 5- (4-diethylaminophenylazo) -8-hydroxyquinoline (DEPAQ) with vanadium (V) was studied. The results showed that vanadium (Ⅴ) forms a 1: 2 red complex with DEPAQ in the buffer medium of pH5.0 ~ 7.0 in the presence of TritonX-100. The maximum absorption wavelength is 525 nm and the apparent molar absorptivity ε = 4.74 × 10 ~ 4L · mol ~ (-1) · cm ~ (-1). Beer’s law is obeyed for the vanadium content in the range of 0-30 μg / 25 ml. In the presence of CyDTA and sodium fluoride for the determination of vanadium in steel samples, the results were satisfactory.