A new simultaneous spectrophotometric method for determination of iron(II) and iron(III) in natural waters

A new analytical method employing di-2-pyridyl ketone salicyloylhydrazone (DPKSH) as a colorimetric chelating agent for simultaneous spectrophotometric determination of iron(TI) and iron(III) in natural waters has been developed. Both of the complex ions show an absorbance maximum at 375 nm, with 4.21 x 10(4) and 1.26 x 10(4) 1.mol(-1) cm(-1) as the molar absorptivities, respectively, for Fe(II) and Fe(III). DPKSH complexes with Fe(II) show another absorbance maximum at 644 nm and a molar absorptivity equal to 1.27 x 10(4) 1.mol(-1) cm(-1). The detection limits are 0.09 muM for Fe(II) and 0.22 muM for Fe(II + III). Concentration approaches were done by using data from five analytical curves for Fe(II), Fe(III) and Fe(II + III) solutions and the use of the respective equations was evaluated in respect on the accurity. Analytical interference studies on some ions probably found in natural waters have also been carried out. This analytical method was used to determine Fe(II) and Fe(III) in natural waters and compared to the 2,2'-bipyridyl and Atomic Absorption spectroscopy methods.