Extraction and Measurement Techniques 49 



5 10 15 MG/L 



CONC. 2,4D 



Fig. 25. The chromotropic acid color lest for 2,4 D (I.cTourneau and Krog, 1952). 



CONC. lAA 



15 20 25 MG/L 



Fig. 26. The relationship between concentration of indoleacetic acid and pH 



(Brauner, 1953). 



