Spectrophotometric Determination Of Bismuth (III) Using An Organic Reagent 2-Methyl -4- (3,4- Dihydroxy Phenyl ) Thiazole Hydrochloride


A preliminary study of the reaction between the reagent (2Me) 2-Methyl-4-(3,4-dihydroxy phenyl) thiazole hydrochloride as thiazole derivatives with some metal ions , and a spectrophotometric method for the determination of Bismuth (III) with this reagent was established. The wavelength of maximum absorption for the complex formed between this ion with this reagent was found to be (328) nm for bismuth, the optimum conditions for the determination of this ion was employed , such as the volume of reagent solution , time, temperature and effect of pH. Calibration curves were constructed and Beer’s law was obeyed in the range of (0.3-10) ppm for bismuth with a correlation coefficient (r = 0.9983) with molar absorptivity ε= 9.529x103 L. mol-1. cm-1 The stoichiometry of the soluble formed complex was investigated by both the continuous variation and mole ratio methods , the ratio (M:L) was (1:1) for bismuth complex . The degree of dissociation (α) and the stability constant (Ksta.)of the complex was calculated . Where (α=0.160 , Ksta.=1.34x105 L. mol-1) for bismuth complex, this prevails that this complex have a high stability . Precision and accuracy of the analytical procedure showed for (5.0) ppm of Bi(III) that R.S.D% was equal to (0.76)% and (Erel. , Re )% were found to be (2.0, 102.0 )% for this ion , with detection limit equal to ( 0.109) ppm for Bi(III).Its complex was showed to be neutral , by passing a solution of each complex through cationic and anionic resin. The interferences of Hg2+ , Fe3+ , W6+ , Mo6+ ions on Bi+3 as well as the studied ions were described , and they masked with suitable masking agents