Determination of Vanadium by Spectrophotometric Method with 2-(5-Carboxy-1,3,4-Triazolylazo)-5- Diethylamino-Benzoic Acid
GE Chang-hua, PAN Fu-you *, LIANG Hua-ding (Department of Chemistry, Taizhou College, Linhai, Zhejiang, 317000)
The conditions of colour reaction of a new reagent 2-(5-carboxy-1,3,4-triazolylazo)-5-diethylamino-benzoic acid(CTZDBA)with vanadium(Ⅴ) are studied. The results show that the new colour reagent reacts with vanadium to form a stable purple red complex(1∶2 by mole) in the medium of HAc-NaAc at pH 3.0. The apparent molar absorptivity is 4.06×10 4 L·mol -1·cm -1 and maximum absorption wavelength is at 583 nm. Beer's law is obeyed in the range of 0～0.8 mg/L for V(Ⅴ). The method has been used for the determination of vanadium in an aluminium alloy sample with satisfactory results.