Analytical Studies on Metal Complexes in Solution

Analytical Studies on Metal Complexes in Solution

Analytical chemistry is the study of separation, identification and quantification of the chemical components of natural and artificial materials. Mainly analytical chemistry deals with quantitative and qualitative analysis. It has applications in chemistry, biochemistry, biology, geology and other sciences and also in industries. Many analytical methods occupy a unique position because of its simplicity, less expensive instrumentation, high sensitivity and selectivity. A great development in spectrophotometry is based on development and measurement of colour. Molecules which do not give colour by themselves develop appreciable colour on reaction with chromogenic reagents and provide a method of analytical determination of molecules. So efforts are being directed towards finding suitable reagents, which have characteristic absorption with metal ions in spectrophotometric analysis. Molybdenum and vanadium are important elements both for industry and for biological systems The simultaneous determination of these metal ions in various samples are of great importance. Therefore efforts are being directed towards finding suitable reagents, which have characteristic colour reactions with microgram amounts of metal ions of interest for spectrophotometric analysis. Salicylaldehydep-chlorophenyl thiosemicarbazone(SAPCPTSC) as a chromogenic reagent for the extractive spectrophotometric determination of Vanadium(V) and Molybdenum(VI) is presented in this study. The reagent SAPCPSC gave instantaneous and stable yellow colour with Vanadium(V) and Molybdenum(VI) in the acidic pH range. The colour reactions in detail has been explored and the possibility of spectrophotometric determination of the micro amounts of vanadium(V) and molybdenum(VI) is established with necessary conditions. The stoichiometry of the complex is established by Jobs method of continuous variation and confirmed by mole ratio method. The stability constant, the standard deviation and the coefficient of variations are reported. Derivative spectrophotometry enables the exact determination ?maxof this type of metal ions. Molar absorptivity, Sandells sensitivity and quantitation limit values show that the proposed method is highly sensitive. The coloured species were stable over several hours making the method practicable. Many cations and anions do not interfere with the determination even if they are present in excess. Surfactants have the ability to solubilise a water insoluble complex or ligands and so micellar medium has also been employed so as to avoid the use of toxic organic solvents. The proposed method has been successfully applied for the determination of molybdenum and vanadium in steel samples.KEY WORDS: Salicylaldehydep-chloroanilinethiosemicarbazone, vanadium, molybdenum, derivative spectrophotometry, micellar medium, simultaneous determination. KEY WORDS: Salicylaldehydep-chloroanilinethiosemicarbazone, vanadium, molybdenum, derivative spectrophotometry, micellar medium, simultaneous determination.

S. Iyer Vidhya

Chemistry