Synthesis And Spectrophotometric Study of 2-[(6-Nitro - − 2 - benzothiazolyl)azo]-4,5-diphenyl imidazole As Analytical Reagent For Determination Of Cadmium(п)

Abstract

A sensitive ,selective and rapid spectrophotometric method was used for the
determination of trace amounts of cadmium ion by using the reagent 2-[(Nitro-
−2
-
benzothiazolyl)azo]-4,5-diphenyl imidazole (6-NO2BTADI).This reagent reacts with
Cd(п) in the pH rang (7.5-8.5) to from purle complex .Beer’s law is obeyed in the
concentration range of (1-11)μg.ml-1 and the stability constant was found to be
5.11x108L2.mol-1.The molar absorptivity and sandell’s sensitivity values of Cd(п)
complex were found to be 0.135 x 103 L2.mol-1.cm-1 and 2.2 x10-3 μg.cm-3 respectively
at λmax 531 nm. The detection limit , relative standard deviation , relative errors and
recovery values for this spectrophotometric method were found to be D.L=0.237
;R.S.D%= 0.431 ; Erel%=2.85 ;Re %=97.14 .The stoichometry of metal to reagent
(M:L)were 1:2 for Cd(п)-complex by using continuous variation and mole ratio. The
most important interference were due to Co2+,
Ni2+,Cr2+,Mg2+,Ca2+,Zn2+,Hg2+,Ba2+,WO4
2- and suitable masking agents were used
tartaric acid ,oxalic acid ,citric acid and ascorbic acid .