New oxidative electrophilic coupling reactions and their application to spectrophotometric determination of iron(III) in environmental waters, soils and industrial effluent samples

New oxidative electrophilic coupling reagents, 2-amino-2′,5-dichlorobenzophenone (MCB) or 2-amino-5-chloro-2'-fluorobenzophenone (MFB) are exploited for the determination of trace concentrations of iron(III) in environmental water and soil samples. The methods were based on oxidation of the electrophilic coupling reagents, 2-amino- 2′,5-dichlorobenzophenone (MCB) or 2-amino-5-chloro-2'-fluorobenzophenone (MFB) by iron(III) and coupling with phenoxazine (PNZ) in acidic medium to yield red color derivative having an absorbance maximum at 520 nm, which is stable up to 12 h. Beer’s law are obeyed for iron in the concentration ranges 0.31-1.2121 μgmL-1 and 0.42-1.41 μgmL-1, respectively. The optimum reaction conditions and other important analytical parameters were established. Interference due to various non-target ions was also investigated. The developed methods were applied to the analysis of iron(III) in various matrices. The performance of developed methods were evaluated in terms of Student’s t-test and variance ratio F-test that indicate the significance of developed methods over reported method.