THE USE OF CHROMOTROPIC ACID FOR THE QUANTITATIVE DETERMINATION OF 2,4-DICHLOROPHENOXYACETIC ACID

Abstract

A spectro-photometric method for the quantitative detn. of 2,4-D is descr. which depends on its reaction with chroniotropic acid in the presence of hot coned. H2SO4. The absorption spectrum of the colored reaction product was detd. and quantitative measurements were made at 580 m[mu] Beer''s Law is followed provided chromotropic acid is added in specified amts. The method can be used to determine 2,4-D in the range 2.5 to 35 [mu]g. under the conditions of the procedure. Several compounds related in structure to 2,4-D and compounds known to yield formaldehyde upon acid hydrolysis as well as indoleacetic acid and skatole react to give similar colored products under the conditions of the method. Nitrite, nitrate, chromate, and dichromate ions also yield colored solns.