Thermometric determination of trace amounts of vanadium(V) in petroleum products using the chromotropic acid-bromate reaction

Abstract

A rapid and sensitive thermometric method for the determination of trace amounts of vanadium(V) based on its catalytic effect on the rate of oxidation of chromotropic acid by bromate in acidic solution is proposed. The reaction rate was obtained graphically from the temperature-time curve. Using the given concentrations of reactants, the extent of oxidation of chromotropic acid is proportional to the concentration of vanadium(V) present. Concentrations in the range 1.2–130 p.p.b. can be determined. The relative standard deviation for 50 p.p.b. of vanadium(V) was 2.2%. As other ions at a 500-fold excess do not interfere, the method has been applied to determine vanadium(V) in petroleum derivatives.