Ratios of Fourier to orthogonal function coefficients: spectrophotometric determination of tetraenes in amphotericin B

Abstract

Ratios of Fourier function coefficients to their analogous orthogonal function coefficients are proposed as purity indices during spectrophotometric analysis. Hence, a₁/p₂(where a₁= coefficient of cosx and p₂ is the coefficient of P₂) calculated for a set of absorbances is independent of concentration and is sensitive to the presence of interferents. The concentration of tetraenes in amphotericin B has been determined by this ratio, calculated from absorbances measured at 6-nm intervals from 264 to 294 nm.