Extraction-photometric determination of vanadium with 4-(2-pyridylazo)resorcinol in the presence of tetrazolium chloride

To develop the method of photometric determination of V in objects with prevailing content of Ti, Cu and Fe its comple-- xing with 4-(2-pyridylazo) resorcinol (PAR) in water-propanol medium in the presence of tetrazolium chloride (TZC) has been studied. It is shown, that at reagent excess the complex of the composition V(5):PAR:TZC=1:2:1 is formed, and at metal excess - 1:1:1. The complex is well extracted by chloroform (extraction constant 6.3x102) and it has a high molar coefficient of quanching (47000). A method of extraction photometric determination of vanadium in soils, permitting to determine V in the presence of Ti, Cu and Fe without their separation, is developed