Spectrophotometric method for determination of atrazine and its application to commercial formulations and real samples

A simple sensitive spectrophotometric method has been developed for the determination of atrazine in herbicide formulations and real samples. The method was based on the reaction of atrazine with pyridine to form a quaternary halide which in the presence of alkali forms a carbinol base. The heterocyclic ring of the carbinol base breaks and forms the glutaconic dialdehyde. The glutaconic dialdehyde group was coupled with sulfanilic acid to form a yellow coloured product having max 450 nm or coupled with aniline to form a orange red coloured product having max 480 nm. The Beer's law was obeyed over the range from 0.1 to 25 g mL-1 and molar absorptivity 1.5 104 L mol-1 cm-1 for sulfanilic acid, and from 0.08 to 12 g mL-1 and molar absorptivity 1.3 104 L mol-1 cm-1 for aniline were observed. The reaction conditions and other analytical parameters were optimised. The proposed method has been successfully applied for the analysis of commercial formulations and real samples.