Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2014, 6(8):5-8 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 5 Novel simultaneous spectrophotometric determinations of Bi (III), Sn (II), Mn (II), V (III) and Se (II) ions in mixed aqueous solutions *Ekere N. R., Okoye C. O. B. and Ihedioha J. N. Analytical/Environmental Chemistry Laboratory, Department of Pure & Industrial Chemistry University of Nigeria, Nsukka, Enugu Sate, Nigeria _____________________________________________________________________________________________ ABSTRACT This paper reports a novel simultaneous uv-vis spectrophotometric determination of Bi (11I), Sn () Mn (II),V (III) and Se (II) in mixed aqueous solution using 3,3′,4′,5,7 – pentahydroxy flavuylium (cyanidin) as complexing agent. The maximum absorption wavelengths (λ) of Bi – cyanidin; Sn – cyanidin; Mn –cyanidin, V – cyanidin and Se – cyanidin complexes were 277 nm, 232 nm 240 nm, 272 nm and 251 nm respectively as against that of pure cyanidin which was 280 nm at the determined optimal pH value of 5. Spectral overlap did not occur among the metal complexes and linearity occurred with the range of 0.50 ppm to 2.5 ppm. This method has potentials for a simple, cheap, rapid and eco-friendly way of trace heavy metals determinations in biological and environmental samples. Key words: Spectrophotometry; trace metals; cyanidin, aqueous, bismuth (III), vanadium (III) selenium (II), complexes. _____________________________________________________________________________________________ INTRODUCTION Determination of trace heavy metals present in the environment has been given prominence due to the toxicity of some of them to man and the environment. Several methods have been developed for their simultaneous determination in environmental, food, drugs and biological samples. Among these techniques are adsorptive stripping voltametry [1, 2], atomic absorption spectroscopy [3] and chromatography [4]. Other methods offering simultaneous determination in mixed aqueous solutions as well as in environmental, industrial and biological samples are plasma based techniques such as inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and inductively coupled plasma-mass spectroscopy (ICP-MS) [5]. Among these methods, atomic absorption spectroscopy (AAS) is the most common. All these methods produce robust results and are quite sensitive and fast but their major setbacks are prohibitive cost of the instruments, sophistication of technical know-how, running and maintenance cost and high cost of chemicals and reagents. There are also environmental concerns such as release of mercury vapour into the air during AAS determination. Ultra violet – visible (uv-vis) spectroscopy is a traditional and widely used technique for single element determination of metal ions in solutions [5,6,7]. Some workers have achieved simultaneous analysis of metals using various complexometric methods with uv-vis spectroscopy [4,5,8,9]. Most of these ligands are not environmentally friendly [10]. The use of flavonoids as analytical reagents have been reported, based in their abilities to form complexes with some p, d and f-electron metals and the complexes formed make the basis of determination of metals by uv–vis spectrophotmetry and spectrofluorimetry. Morin and Quercetin have been used in determination of A (III) [5], Cr