Graphical methods of simultaneous determination of molar absorptivity and stability constant of 1 : 1 metal complex using spectrophotometric data : FeIII-5-nitrosalicylic acid complex

Department of Chemistry, Ewing Christian College, Allahabad, Uttar Pradesh, India

Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India

E-mail : sharda 100@rediffmail. com; mcc46@rediffmail.com

Manuscript received 14 September 2006. revised 23 July 2007, accepted 23 August 2007

A comparative study on four well known graphical methods for simultaneous determination of molar absorptivity and stability constant of 1 : 1 metal complex using spectrophotometric data was carried out to evaluate the validity of these methods. In order to determine stability constant, Fe^III-5-nitrosalicylic acid system was studied in the pH range 2-3. It was found that stability constant values obtained by these methods are lower in comparison to the value obtained from a rigorous graphical method developed in this laboratory. This method is also helpful in obtaining the value of molar absorptivity simultaneously.