Synthesis of 2-[(2-َCarboxy-4-nitrophenyl) azo]-4,5-diphenyl imidazole (CNPAI) and it's usage as an analytical reagent for the determination of Copper (II) and Ferric (III) ions

Abstract

A study for the determination of Cu2+ and Fe3+ using 2-[(2-َCarboxy-4-nitrophenyl)
azo]-4,5-diphenyl imidazole (CNPAI)is performed, the wave length of maximum
absorption for Copper (CNPAI) and ferric (CNPAI) complexes are 529 and 533 nm
respectively.
After optimum condition were constructed, Beer's law was obeyed in the range (0.4-11)
ppm for copper and (0.3-10) ppm for ferric ions, the linearity ( R2 ) was (0.9996),
(0.9995) while the molar absorpitivty (ε) was 9.5631 x 104 L.mol-1.cm-1, 7.4414 x 104
L.mol-1.cm-1 and Sandell sensitivity was 6.6 x 10-4 μg.cm-2, 8.7 x 10-4 μg.cm-2 for Cu(II)
and Fe(III) complex respectively.
The stoichometry of metals to reagent were 1:1 for copper (CNPAI) and 1:2 for ferric
(CNPAI) complexes, Precision and accuracy of the analytical procedure for copper and
ferric were R.S.D % (1.02 , 1.56)% whereas (Erel., Re) % were (-2, 98) %, (-3, 97) %,
detection limit was (0.03, 0.056) ppm, the interferences of ions (CrO4
2-, Mn2+, Co2+,
Ni2+, Zn2+, Cd2+ Ag+) were studied and masked by using appropriate masking agents.