International Science Community Association Research Journal of Chemical Sciences 2231 - 606X 5 2 2015 February 18 Simultaneous Second Derivative Spectrophotometric Determination of Gold and Cobalt 4 7 EN Okechukwu R.I. 1 Department of Biological Sciences, Federal University of Technology, Owerri, Imo State, NIGERIA Iwuchukwu A.C. 2 Anuforo H.U. 3 Kumar D.Prem 1 Department of Chemistry, Sri Krishnadevaraya University, Anantapur–515 003, A.P., INDIA PraveenKumar A. 2 Reddy P.Raveendra 3 > Research Paper 2014 12 26 2015 February 18 A simple, sensitive, and selective second order derivative spectrophotometric method has been developed for the simultaneous determination of gold(III) and cobalt(II) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent (HMBATSC) reacts with Au(III) and Co(II) at pH 6.0, forming soluble blue and brown species, respectively. The second order derivative spectrum of [Au(III)–HMBATSC] exhibits reasonably sufficient amplitude at 435 nm and zero amplitude at 455 nm, and [Co(II)–HMBATSC] shows maximum amplitude at 455 nm and zero amplitude at 435 nm. This difference in amplitudes was utilized to develop a second order derivative spectrophotometric method for the simultaneous determination of Au(III) and Co(II) in a mixture without solving the simultaneous equations by measuring the second derivative amplitudes at 435 nm and 455 nm, respectively. Further, the Beer’s law was obeyed in the range 0.1178–3.7712 ml-1 of Au(III) and 0.1225–3.7400 µg ml-1 of Co(II). A large number of foreign ions do not interfere in the present method. The method is applied to the simultaneous determination of Au(III) in Rheumartho gold and Co(II) in Vitamin B12samples. Copyright@ International Science Community Association