التقدير الطيفي لكميات ضئيلة لايوني النحاس(ll) و الزئبق(ll) باستخدام مشتق (ازو) جديد ودراسة دوالها الثرموديناميكية وتطبيقاتها التحليلية

Spectrophotometric Determination of Micro Amount of copper(ll) and mercury(ll) ions Using a new (Azo) Derivative, Study of Thermodynamic Functions andTheir Analytical Application

Summary:

          The study included the preparation and diagnosis of the new ligand 4,5-bis(4-methoxyphenyl)-2-(m-tolyldiazenyl)-1H-imidazole (BMTI), which is one of the Azo compounds using the traditional nitrogenation method by duplicating the diazonium salt of the m-toluidine compound with the amidazole derivative and conducting a preliminary study with (9) Metallic ion to determine the two ions copper and mercury. The maximum absorpation of the reagent dissolved in ethanol (λmax= 446.5nm), and the formation of the copper(II) and mercury(ll) complexes formed with the reagent, in addition to that, the best conditions for the reaction of these two ions with the reagent were studied, such as the acidity function, the concentration of the reagent and duration of time For the stability of the two complexes. The temperature, the order of addition of the reaction components, the calibration curves for each of these two ions were shown with the reagent, it was raound that Beer,s law over the range of the copper(II)complex within the concentration ranges (3.149×10-7 – 1.889×10-5M) with the linearity coefficient (R2 = 0.9989) and the absorbance value. The molar absorptivity (ε) is equal to (1.110x104L.moL-1 .cm-1) and Sandel’s sensitivity is equal to (0.00588 μg/cm2), while mercury (ll) is within the range of concentrations (1.994×10-7-8.973×10-6M) and with a coefficient of linearity ( R2 = 0.9988). value of the molar absorptivity (ε) = (1.310x104L.moL-1.cm-1) sandel sensitivity equal (0.00153 μg/cm2) .The equivalence of the two complexes was studied by finding the ratio of the metal ion to the reagent (M: L) using the continuous changes method and the molar ratio and the Mollard method for the copper(II) and mercury(ll) complexes . II The stability constant (Kstab) for copper and mercury complexes were (K = 2.649×1010) and (K = 1.460×109) repectively. In addition, the thermodynamic functions (ΔH , ΔG and ΔS) were calculated for both complexes, where the results indicated that the reaction of forming the copper(II) complex is exothermic and the mercury(ll) complex is endothermic. The study demonstrated that interferance of the presence of a number of cations and anions ions as potential interactions when estimating copper(II) and mercury(ll) 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 were not show any effect. Remarkably, the charge of dissolved complexes was determined by measuring the conductivity of the two complexes, so the used complexes were not charged. The accuracy and precision of the analytical method was determined using three different concentrations for each ion, so the values of the percentage of relative standard deviation for the copper(II) ion ranged between (0.720-2.110%) and the relative recovery ranged between (95.829% -103.930%) for the mercury(ll) ion values ranged between (0.710-1.420%) and the relative recovery ranging between (97.703% – 99.197%), through which the detection limit was calculated for the copper(ll) ion (3.590×10-8M), equivalent to (0.0114 μg /mL). The mercury(ll)ion is equal to (1.435×10-7M), equivalent to (0.0288μg / mL), which indicates the sensitivity of the spectral method using this reagent (BMTI).The sediments of the reagent and the two complexes have also been studied by determining some of their physical characteristics such as melting point, solubility, molar conductivity. The method was applied to standard laboratory prepared III solutions as it was applied to samples of tea leaves and tap water to determine the concentrations of copper (II) and a model of dental filling to determine the concentrations of copper(II) ion. Also, the method was applied to samples of well water to determine the concentration of mercury. The method was found a high in sensitivity and accurcy.