Nomograms for calculating and testing the Morton and Stubbs correction in the spectrophotometric assay of vitamin A

Abstract

Two nomograms (for vitamin-A alcohol in isopropyl alcohol and for vitamin-A acetate in absolute ethanol) are given for the rapid application of the Morton and Stubbs correction without numerical calculation.The Morton and Stubbs correction sometimes leads to erroneous results, and a practical test for the reliability of Ecor. is proposed. The test can be carried out in a few minutes by using nomograms, and makes it possible to ascertain whether or not the irrelevant absorption is approximately linear over the wavelength range between the two fixation points a t six-sevenths.I 3

Ultraviolet Spectrophotometry

“…(88). Nomograms for use in the assay of vitamin A and corrections needed for nonlinear background adsorption were presented (100). Nioviobiocin and its dehydro derivative were determined by the two-component analysis method (122).…”