Analytical Sciences

A Comparative Spectrophotometric Study Using Ferrozine and 1,10-Ortho-phenanthroline to Evaluate the Iron Redox Ratio (Fe²⁺/ΣFe) in Glass Prepared by Microwave Heating

Biswajit MANDAL,* Prasanta Kumar SINHA,** Ranjan SEN,* and Ashis Kumar MANDAL*

*Glass Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata-700032, India
**Materials Characterization and Instrumentation Division, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S. C. Mullick Road, Kolkata-700032, India

In the present study, Fe-doped barium borosilicate glass has been melted at 1250°C under microwave heating. The iron redox ratio (Fe²⁺/total Fe) in the glass is investigated by two spectrophotometric methods. A novel decomposition technique has been optimized to measure the ferrous oxidation state in glass. Ferrozine was chosen as a specific complexing reagent; it forms a deep violet color complex with Fe²⁺ and has a broad absorbance peak centered at ∼562 nm. 1,10-ortho-phenanthroline develops an orange color complex with Fe²⁺ (having an absorbance peak centered at ∼510 nm) and has been used to determine ferrous ion in glass. Both the methods are compared and the estimated redox ratio was found to be higher in the ferrozine method. The error limit of measurement has been determined as 0.012 and 0.023 for the ferrozine and 1,10-ortho-phenanthroline methods, respectively.

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