This article presents the study of the complexation behavior of (E)-3-(((1-methyl-3-oxo-2-phenyl- 5λ³-pyrazolidin-4-yl)diazenyl)methyl)pentane-2,4-dione (R1) with Fe(III) ions using the extractive spectrophotometric method. Different organic solvents were evaluated as extractants, among which 1- butanol provided the highest extraction efficiency. Optimal conditions for complex formation and extraction were established, revealing that Fe(III) predominantly exists as Fe(OH)₂⁺ under the experimental conditions at pH=5. The absorption spectrum of the Fe(III)-R1 complex was recorded across a pH range of 1–6, showing maximum absorbance at pH 5 and λmax = 540 nm. The method obeyed Beer’s law over the concentration range of 0.112–3.36 μg/mL. The Sandell sensitivity was calculated as 0.0049 mg/cm², and the extraction efficiency reached 99.4%. The detection limit was determined to be 0.032 μg/mL. The method was successfully applied to the determination of Fe(III) in environmental water samples from the Zira district of Baku. Results were consistent with those obtained by atomic absorption spectroscopy (AAS), confirming the accuracy and reliability of the proposed technique.
Notes:Abstract. This article presents the study of the complexation behavior of (E)-3-(((1-methyl-3-oxo-2-phenyl-5λ³-pyrazolidin-4-yl)diazenyl)methyl)pentane-2,4-dione (R1) with Fe(III) ions using the extractive spectrophotometric method. Different organic solvents were evaluated as extractants, among which 1-butanol provided the highest extraction efficiency. Optimal conditions for complex formation and extraction were established, revealing that Fe(III) predominantly exists as Fe(OH)₂⁺ under the experimental conditions at pH=5. The absorption spectrum of the Fe(III)-R1 complex was recorded across a pH range of 1–6, showing maximum absorbance at pH 5 and λmax = 540 nm. The method obeyed Beer’s law over the concentration range of 0.112–3.36 μg/mL. The Sandell sensitivity was calculated as 0.0049 mg/cm², and the extraction efficiency reached 99.4%. The detection limit was determined to be 0.032 μg/mL. The method was successfully applied to the determination of Fe(III) in environmental water samples from the Zira district of Baku. Results were consistent with those obtained by atomic absorption spectroscopy (AAS), confirming the accuracy and reliability of the proposed technique.