A spectrophotometric method for the determination of vanadium(V) and cerium(IV) in some water samples using an oxidative nucleophilic coupling between catechol and nitro aniline

摘要

A simple, rapid and a sensitive spectrophotometric method is developed here for the determination ofudVanadium(V), system 1 or Cerium(IV), system 2 in some water samples using catechol as a nucleophilic couplingudreagent with p-nitro aniline producing a chromogen. The method is based on catechol oxidation byudvanadium(V)/cerium(IV) followed by its nucleophilic coupling with p-nitro aniline in acid medium forming a dyeudwith λmax510/490nm respectively. The system 1 obeys Beer’s law in the range, 3μg ml-1 – 24 μg ml-1 and system 2udin the range, 4 μg ml-1 - 20 μg ml-1. The molar absorptivity values for system 1 and system 2 were found to beud1.036 x 103 l mol-1cm-1 and 1.39 x 103 l mol-1cm-1 respectively with the corresponding Sandell’s sensitivity values,ud0.0492 μg cm-2 and 0.1001 μg cm-2. The systems were used for the determination of vanadium(V) and cerium(IV)udin spiked water samples. The results obtained by both the systems were reproducible. The optimum reactionudconditions and other important analytical parameters were established to enhance the sensitivity of the proposedudmethod. The interference of various non- target ions was also studied.