RESUMO
In this paper, a fast, cheap, simple, sensitive and selective spectrophotometric method based on high spin peroxo-Fe(III)-EDTA complex in the alkaline medium was developed for the determination of hydrogen peroxide (H2O2) in real water samples. The purple-coloured complex with a maximum absorbance at a wavelength of 525 nm was formed. Various parameters such as type of stabilizer reagent and its concentration, reaction time, Fe(III), EDTA and NH3 concentration were optimized. The method was confirmed with the Beer's law with a molar absorption coefficient of 267.36 L mol-1 cm-1 in the 8.3 ×10-6 -4.08 ×10-3 mol/L concentration range. Sandell's sensitivity of the proposed method was also calculated as 0.188 µg/cm2 . LOD and LOQ were determined as 2.5 ×10-6 and 8.3 ×10-6 mol/L, respectively. Intraday and interday relative standard deviation of the proposed method for 2.0 ×10-4 mol / L of H2O2 were found as 1.5% and 6.1%, respectively. The developed method is suitable for fast monitoring of H2O2 in different types of aqueous water samples without any sample preparation steps and acceptable recovery values between 90% and 118% were obtained. In the sample analysis, H2O2 removed solutions from the real water samples were used for blank correction in their analysis and this process provides more reliable and accurate results in real sample analysis.
