Extraction of Co(II) by Isocyanate Treated Graphite Oxides (iGOs) Adsorbed on Surfactant Coated C18 Before Determination by FAAS

A simple, highly sensitive, accurate and selective method for determination of trace amounts of Co(II) in water samples is presented. Isocyanate treated graphite oxides (iGOs) solid phase extraction adsorbent was synthesized by covalently isocyanate onto the surfaces of graphite oxides. The stability of a chemically (iGOs) especially in concentrated hydrochloric acid which was then used as a recycling and pre concentration reagent for further uses of (iGOs). The method is based on (iGOs) of Co(II) on surfactant coated C18, modified with a isocyanate treated graphite oxides (iGOs). The retained ions were then eluted with 4 mL of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 nm for Co. The influence of flow rates of sample and eluent solutions, pH, breakthrough volume, effect of foreign ions on chelation and recovery were investigated. 1.5 g of surfactant coated C18 adsorbs 40 mg of the iGOs which in turn can retain 15.2±0.8 mg of ions. The limit of detection (3σ) for Co(II) was found to be 3.20 ng L-1. The enrichment factor for both ions is 100. The mentioned method was successfully applied on determination of Cobalt in different water samples. The ions were also speciated by means of three columns system.