Report on Ultraviolet Spectrophotometric Methods for Drugs (Phenylethylamines)

Corrections for Background in Spectrophotometry Using Difference-in-Absorbance Values. Application to Vitamin A.

“…Another approach to the general problem of background absorption is the graphically or mathematically elaborated base line technique (8,8,7,11,14, 80, 85). Davidow and Woodard (5) and Rotondaro (18) have provided excellent practical examples of this kind of correction. Most workers who apply this technique in practice apparently position the baseline in a somewhat intuitive or empirical fashion.…”

“…In still another approach to the problem of background interference, Jones, Clark, and Harrow (11,18) developed a technique based on a variable reference or spectrophotometric neutralization in which the concentration of the reference (known) solution is varied during the determination until the absorption of the compound in the reference solution and that of the same compound in the unknown solution are equalized. The concentration of the compound of reference in the unknown solution is then identical with that of the compound in the reference (known) solution.…”