Diode-array detectors in flow-injection analysis Mixture resolution by multi-wavelength analysis

Abstract The application of diode-array spectrophotometers to multi-component analysis by flow-injection analysis is reported. Two different aspects are considered: ( a ) the obtainment of a reproducible spectrum corresponding to the maximum of the FIA peak, and ( b ) the mathematical treatment involved in determining the mixture of components. The spectrum is recorded by two different procedures according to the type of injection system used. The mixtures are resolved with the aid of three different treatments: ( a ) a linear equation system, ( b ) a multi-component analysis program (Hewlett-Packard) and ( c ) a graphical method (multi-wavelength linear regression analysis). All three procedures have been applied to the determination of Fe(II) and Fe(III) with a mixture of 1,10-phenanthroline and sulphosalicylic acid.