PREPARATION OF NEW AZO REAGENT FOR EVALUATION OF NICKEL (II) IONS IN DIFFERENT SAMPLES USING CLOUD POINT METHOD

New azo reagent(2-[Ceffodoxime azo]-2-Doxycycline) preparation by coupled reaction. The reagent was diagnosed by spectral methods using infrared (FTIR) and (UV. –Vis.) as an identification using( HNMR) spectrum and (C.H.N).This reagent use to determination nickel (II) ion as a pair ion complex that extracted and estimated according to the cloud point extraction(CPE) technique in enrichment layer ,after adjusting the optimal conditions and affected factors in efficiency extraction processes. The ion pare complex of nickel(II) is estimated according to the spectral method at λ max =438 nm . The optimization of complexation and extraction conditions by (CPE) investigated as well as optimum pH =9 , critical concentration of TX-100 was 0.5mL, heating time=85C˚. Thermodynamic parameters of CPE for extraction process of the ion-pair association complex in Triton X-100 were also considered ΔH = 213.031102KJ ,ΔG=-63.1331372 KJ and ΔS =771.40849J That referred endothermic reaction. with Limit of Detection (LOD=1.0303 μg mL-1) and Limit of Quantitation (LOQ=10.303 μg mL-1) , Molar absorptivity (Ɛ= 5609.8L.mol-1.cm-1). The Stiochoimetry study to determination complex stricture that ratios of metal: reagent obtained are (1:1). Under the optimized conditions of a 10 mL sample gave preconcentration and enrichment factors are(20 and 17.6875) respectively with Sandell's sensitivity( 1.5506 x10-6 μg cm-2/0.001A.U) . The calibration curve linear in the range of 1-8 ppm with a correlation coefficient of 0.9999. The relative standard deviation for replicate determinations at (30) μg 10mL−1 level is 58.63%. The proposed method applied for the determination of nickel in fish, vegetables, plant leaves and water which gave satisfactory results.