Aplicaciones analíticas de la reducción fotoquímica de la riboflavina el ácido etilenodiaminotetraacético. Determinación de ioduro

Authors

  • T. Pérez Ruiz
  • C. Martínez Lozano
  • V. Tomás Martínez

Abstract

A kinetic study of the photochemical reaction of riboflavin and EDTA (in the absence of oxygen) has been made in connection with development of a new kinetic method for iodide. The reaction is first-order with respect to riboflavin, EDTA and absorbed light-intensity. The rate of photoreduction is strongly pH^dependent, and maximal at about pH 7,5. The photoreduction involves a long-Uved excited state of the vitamin B2 and is dramaticalUy retarded by small amounts of iodide. A tenta'tive mechanism is proposed, and the experimental conditions have been optimized. The variable time method appears to be the most suitable for determination of iodide. A detection limit of 8 [xg/rnl and a casfficient of variation about 3 % can be adhieved. Chloride and bromide do not interfere at levéis below 100-fold mole ratio to iodide. Metal ions do not interfere if enough excess of EDTA is used.

Published

02-07-2021

Issue

Section

Artículos