Spectrophotometric determination of vanadium in crude oil

Spectrophotometric method has been developed for the determination of vanadium after derivatization with 2-pyrrolealdehyde phenylsemicarbazone (PPS). The linear calibration curve was obtained with 2.5-20μg/ml vanadium. Copper(II), cobalt(II), iron(II) and palladium(II) could also be determined separately using PPS with linear calibration curves within 2.5-12.5, 5-15, 2.5-15 and 1-5μg/ml at 362, 355, 355 and 365 nm, respectively. The vanadium in crude oil was determined with relative deviation (RSD) of 2.5-5.0%. The methods have been applied for the analysis of copper from copper wires, cobalt from pharmaceutical preparation and palladium from palladium on barium sulphate with RSD within 2.6-4.5%.