Page 92 - Pharmaceutical Analytical Chemistry III

❑DETERMINATION :

Photometric analysis :

- This method is based on the reaction which takes place

under suitable conditions between para-
aminodimethylaniline ( N,N-dimethyl-1,4-
phenylenediamine), FeCl3 and sulphide ion resulting in
the formation of methylene blue (M B).

NH2 N

Fe(III)

2 + H2S

(H3C)2 N +

(HC)2 N S N(CH3)2

MB