Column chromatographic preconcentration of cobalt and zinc with 3-hydroxy-4-imino(N-2' -pyridyl)-2-methylnaphthalen-1-one adsorbed on naphthalene and their estimation in vitamin and milk samples

Abstract

A sensitive, economical and rapid spectrophotometric method of preconcentration and separation of cobalt and zinc has been developed using a solid chelating resin, 3-hydroxy-

4-imino-(N-2' -pyridyl)-2-methylnaphthalen-1-one (HIPMN) supported on naphthalene. Co and Zn are quantitatively determined using this absorbent in a column in the <i>p</i>H<i> </i>range of

4.0-6.0 and 5.8-8.0 respectively with a now rate of 2 ml min^-1.The metal complex and naphthalene are dissolved out from the column with 10 ml of DMF and the absorbance is measured at 568.5 nm and 466 nm for Co and Zn, respectively. Beer's law is obeyed up to 15 mg l^-¹, for Co and 22 mg l^-¹ for Zn using this method with a sensitivity of 0.035μg cm^-2 for Co and 0.032μg cm^-2 for Zn for log (<i>I</i>₀/<i>I</i>) =0.001. Atomic absorption spectrometry (AAS) is also used to determine the metal ion concentration.