التقدير الطيفي لكميات ضئيلة لايوني الزنك الثنائي والكروم الثلاثي باستخدام مشتقات صبغة الايمدازول , دراسة الدوال الثرموديناميكية وتطبيقاتها التحليلية

Spectrophotometric Determination of Micro Amount for Zn(II) and Cr(III) by Azo Imidazole Derivative, Study of Thermodynamic Functions and

This study. contained the preparation and. characterization of the new. reagent sodium4-((4,5-diphenyl-imidazol-2-yl)diazenyl)-3-hydroxynaphthalene-1-sulfonate (SDPIHN), which is one of the. Azo compounds using the. classic nitrogenation. process by duplicating the imidazole. derivative with the diazonium salt of the 1-amino-2-napthol-4-sulfonic acid compound and conducting. a preliminary study with. 11 metal ion to. determine the two ions zinc and chromium. The maximum absorption of the ligand that dissolved in ethanol (λmax= 463 nm), and the formation of the zinc(II) and chromium(III) complexes created with the ligand in presence of non-ionic surfactant (Triton X-100) . Additionally, the optimal conditions for the reaction of these two ions with the reagent were. investigated , like the acidity. function, the concentration. of Triton X-100, duration of time. for the stability of. the two complexes, concentration. of the ligand, the. temperature, the order. of addition of. the reaction components, the calibration. curves for each of. these two ions were. shown with the ligand, which it was obyed the Beer’s law in the range of the zinc(II) complex with the concentration. ranges (1-11)µg/mL with the linearity coefficient (R2 = 0.9996) and the absorbance value. The molar absorptivity (ε) was equal to (0.2229×104L.moL-1.cm-1) and Sandal’s sensitivity was equal to (0.0293μg/cm2), while chromium(III) was with range of concentrations (1-11)µg/mL and with a coefficient of linearity (R2 = 0.9998). Value of the molar absorptivity (ε) = (0.244×104L.moL-1.cm-1) ,Sandal’s sensitivity equal (0.0213μg/cm2) . The equivalency of the two complexes was investigated by calculating the ratio of the metal ion to the ligand (M:L) using the Job’s method and the mole ratio method for the zinc(II) and chromium(III) complexes. The stability constant (Ksta) for zinc (II) and chromium (III) complexes were (Ksta=5.967×108) and (Ksta=1.125×1014) respectively . Moreover, the thermodynamic functions. (ΔH , ΔG and ΔS) were. calculated for both complexes, where. the outcomes indicated that the reaction of forming the zinc(II) complex. was endothermic and the chromium(III) complex was exothermic. The study demonstrated interference of the presence of a number of cations and anions ions as potential interactions when estimating the zinc(II) and chromium(III) ions, and the addition of appropriate masking agents was studied, as it was found that these ions interact to varying degrees depending on the nature and concentration of the interfering ion, and some of them did not show any effect. Remarkably, the charge of dissolving complexes was determined. by measure the conductivity. of two complexes, resulting in the zinc(II) complex being uncharged while the chromium(III) complex being charged. The accuracy. and precision of the. analytical method were. determined using three various concentrations for each ion , the values of the. relative standard deviation. (RSD%) for the zinc(II) ion ranged between (0.700% – 1.772%) and the relative recovery ranged. between (98.950% -103.930%), the values of the relative. standard deviation (RSD%) for the chromium(III) ion values ranged between (0.552% – 1.250%) and the relative recovery ranging between (97.830% – 101.080%), through which the detection limit was found for the zinc(II) ion (3.475×10-6M), the detection. limit of the chromium(III) ion was equal to (2.194×10-6M), which shows the sensitivity of the spectral technique using this ligand (SDPIHN). Determining physical properties such as melting. point, solubility, and molar conductivity, the sedimentation of the reagent and the two complexes have also been investigated. The method was used to determine the amounts of zinc(II) and chromium(III) ions in the pharmaceutical sample. The method’s sensitivity and accuracy were determined to be high.