A NEW APPROACH FOR AN OLD REAGENT

M.S. DI NEZIO; C. DOMINI; A.G. LISTA; M. PALOMEQUE; BEATRIZ S. FERNÁNDEZ BAND

Prague (CZECH REPUBLIC)

Congreso; 10th International Conference on Flow Injection Analysis (ICFIA), 1999.; 1999

Dithizone (diphenyIthiocarbazone) is an old and known reagent for thedetermination of metals and heavy metals. This reagent requires extractionsteps in chloroform or in carbon tetrachloride before the spectrophotometricdetection.The hard and tedious work of the extraction steps produces: time-consuming,the introduction of systematic errors and a harmful work for the operator,owing to the toxicity of the solvents.The aim of this work is to propose the use of dithizone reagent, dissolved ina micellar medium, for the determination of metals as Hg(II), Cd(II), Cu(II)and Zn(II) with spectrophotometric FIA methods.The purpose of the surfactant is to dissolve the reagent, that represents anadvantageous way, because it lets that the he complex formation betweenmetal and Dithizone, takes place in a micellar medium. The fact of using anaqueous medium is appropriate to develop an simple FIA system for thedetermination of each metal, avoiding the use an assembly with liquid-liquidon-line extraction.Thus, different FIA manifold s were developed for different metal ions, inorder to verify that it is useful to use Dithizone in a micellar medium withFIA methods. The concentration ranges and sensitivities, obtained by FIAmethods, were better than those obtained by batch process [1]. Theimprovement of the proposed methods is being studied with a concentrationon-line manifolds