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Determination of Trace Amounts of Vanadium by Kinetic‐Catalytic Spectrophotometric Methods
Author(s) -
Pouretedal H. R.,
Keshavarz M. H.
Publication year - 2006
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200690106
Subject(s) - vanadium , reagent , chemistry , absorbance , catalysis , detection limit , ion , inorganic chemistry , bromate , analytical chemistry (journal) , chromatography , organic chemistry
Kinetic‐catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium(IV) and/or V(V) ions. The vanadium(IV) as VO 2+ ion and/or vanadium(V) as VO 3 − ion showed a catalytic effect on the kinetic reactions between a color reagent such as methylthymol blue (MTB) or SPADNS and bromate in acidic media. The rate of decrease in the absorbance of the reagent MTB at 440 nm or SPADNS at 510 nm was proportional to concentration of V(IV) and/or V(V) ions in the solution. The linear ranges for determination of vanadium were obtained in the range of 1.0–150 and 5.0–100.0 µg/L by the fixed‐time and slope methods, respectively, with using MTB as reagent. In the presence of SPADNS as reagent, the calibration curves were made in the amplitude 1.0–200.0 and 5.0–150 µg/L of vanadium ion by the fixed‐time and slope methods, respectively. Using fixed‐time method, the limits of detection were obtained to be 0.5 and 0.7 µg/L of vanadium in the presence of MTB and SPADNS as reagents, respectively. Detection limits of vanadium by slope method and reagents of SPADNS and MTB were obtained to be 3.5 and 3.8 µg/L of vanadium, respectively. The proposed methods were applied successfully to determination of vanadium in synthetic and real samples.