Synthesis and Spectrophotometric study of 4-(6- bromo-2-benzothiazolylazo)‎ phloroglucinol as an analytical reagent for determination of bismuth

Abstract EN

A new chromogenic reagent, 4-(6-Bromo-2-benzothiazolylazo) phloroglucinol (6-BrBTAPG), was synthesized by diazo coupling of (2-amino-6-bromo benzothiazol) (2-ABrBT) with phloroglucinol, and used for the spectrophotometric determination of bismuth (III).

This method was simple, sensitive, selective and rapid for reaction between Bi3+ and (6-BrBTAPG), to form a pink complex having a molar ratio of (1 : 1) (Bi-6-BrBTAPG) at pH 7.5.

The molar absorptivity of the complex was 0.2654 × 104 L.mol-1 cm-1 at λ max 538 nm.

Beer’s law is obeyed in the range of (0.5-30) ppm of bismuth, and the stability constant was found to be 3 × 104 L.mol-1.

The relative standard deviation for seventh replicate measurements, recovery, and relative error values of this method were found to be 0.736 %, 101.33 %, and1.33 % respectively.

The interference of foreign ions was also investigated.

All the other ions studied did not interfere with bismuth determination except for Mn2+, Co2+, Fe3+, V5+, and pb2+.

The interferences were eliminated approximately using suitable masking agent.