Ratio Method in Spectrophotometric Analyses

Abstract

A method has been developed for normalized spectrophotometric analyses of multicomponent mixtures in which only the mutual relationships of absorption coefficients are determined rather than the absolute values. The method is intrinsically rapid and accurate, and has been shown to effect a considerable saving in time and materials relative to older methods. ANY system of analysis of a mixture depends on differences .

Light Absorption Spectrometry

“…Some papers emphasize the nature of a method in connection with its applications. Examples are: precision colorimetry and its application to the determination of manganese (286); microspectrophotometry in its application to cytochemical analysis of nucleic acids (199); a method based on the determination of absorption relative to an internal standard (36); the merits of a ratio method in spectrophotometric analysis (218); and the prob- lem of determining two components in a mixture by absorptiometric means (20). Somewhat different are the two papers by Stearns. The first (255) describes the measurement of dye strengths, visually and spectrophotometrically by means of Pineo's formula.…”

Infrared Spectroscopy

“…The general papers in this field include one on the rapid calculation of multicomponent mixtures with punched card machines (233) and a discourse on the ratio method of analysis in spectrophotometric problems (239). This latter is primarily a visible spectroscopy paper but somewhat applicable to the infrared region.…”

Ultraviolet Absorption Spectrophotometry

“…They illustrate the advantages of this differential method, but point out that it requires wider slits than would otherwise be necessary and that in some cases the resulting loss of resolving power and increase in stray radiation might be a handicap. An interesting variation of the usual procedure for multicomponent quantitative analysis is presented by Perry, Sutherland, and Hadden (32). In setting up their calibration they use measurements on solutions of the individual components whose concentrations are not known, the only requirement being that the absorbances (optical densities) fall within the optimum range of 0.4 to 1.0.…”