H Tavallali - Affiliation (Department of …, Payame Noor, Tehran, ۱۹۳۹۵-۴۶۹۷, Islamic Republic of Iran,
M Ostovar - Affiliation (Department of …, Payame Noor, Tehran, ۱۹۳۹۵-۴۶۹۷, Islamic Republic of Iran,
M.A Karimi - Affiliation (Department of …, Payame Noor, Tehran, ۱۹۳۹۵-۴۶۹۷, Islamic Republic of Iran,
A Porhami - Affiliation (Department of …, Payame Noor, Tehran, ۱۹۳۹۵-۴۶۹۷, Islamic Republic of Iran,
G Dailamy-Rad - Affiliation (Department of …, Payame Noor, Tehran, ۱۹۳۹۵-۴۶۹۷, Islamic Republic of Iran,

An-spectrophotometric approach is described for the determination of C۲O۴ ۲- ion in the aqueous medium based on the formation of ArsenazoIII(AAIII) –Cu complex. This system produces a visible color change from red to blue based on the indicator displacement assay (IDA) method due to formation AAIII-Cu complex by addition of Cu۲+ion. In the presence of C۲O۴۲- ion, the solution color returns to red with about ۳۴.۵ nm blue shifts. Determination of C۲O۴۲- ion the linear ranges achieved for UV-Vis absorbance experiment were ۱.۵ - ۴۷ μmolL-۱. The limits of detection was also achived to ۰.۲۳μmol L-۱. Anion species various such as SO۴۲-, S۲O۸۲-, H۲PO۴۲-, CH۳CO۲-, CN-, S۲O۴۲-, SO۳۲-, PO۴۳-, HPO۴۲-, CO۳۲-, NO۳-, SCN-, I-, Br -, Cl- and F- were investigated by AAIII –Cu complex. This complex no indicated spectral and color changes with these species. The method was applied to the determination of oxalate ion in aqueous solutions samples.

Colorimetric, chemsensor, ArsenazoIII –Cu complex, C۲O۴۲- ion