Synthesis and Spectrophotometric study of 4- (6- Nitro-2- benzothiazolylazo) resorcinol as an analytical reagent for the determination of zinc.

Abstract

4-( 6-Nitro-2-benzothiazolyl azo )resorcinol (6-Nitro BTAR) has been synthesized , and
was used as a reagent for the spectrophotometric determination of microgram amounts of zinc
ions. This method sensitive, selective and rapid for reaction between Zn2+ and (6-Nitro
BTAR), to form a brown complex having a molar ratio of 1:2 (Zn - 6-Nitro BTAR) at pH 6.
The molar absorptivity of the complex is (5846 .7 L.mol-1.cm-1) at λmax 462.5 nm .Beer’s law
is obeyed in the range of 0.2 –3 μg.ml-1 and the stability constant was found to be 1x108
L².mole²-.
The relative standard deviation, recovery and relative error values of this method was
found to be R.S.D% = 1.6, Re % = 98.84,and Erel % = -1.16. The most important interference
were due to Hg2+
,Cd2+,CrO4
2-, Ag+, Ni2+ and Co2+ , and suitable masking agents were used.
The method was applied successfully for the determination of zinc in clay of shaat Al-Hilla.