Document Type : Research Paper
A simple, highly sensitive, accurate and selective method for determination of trace amounts of Pb(II) in water samples is presented. A novel Graphene oxide with covalently linked porphyrin solid-phase extraction adsorbent was synthesized by covalently linked porphyrin onto the surfaces of graphite oxides. The stability of a chemically (GO-H2P) especially in concentrated hydrochloric acid was studied which used as a recycling and pre-concentration reagent for further uses of (GO-H2P). The method is based on (GO-H2P) of Pb(II) on surfactant coated C18, modified with a porphyrin-treated graphite oxides (GO-H2P). 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 Pb. 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 Schiff's base which in turn can retain 15.2 ± 0.8 mg of each of the two ions. The limit of detection (3σ) for Pb(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 lead in different water samples. The ions were also speciated by means of three columns system.