An Anionic Resin Modified by di-2-Pyridyl Ketone Salicyloylhydrazone as a New Solid Preconcentration Phase for Copper Determination in Ethanol Fuel Samples

The adsorption of DPKSH onto anionic resin was investigated at 25 +/- 1 degrees C and pH 12 on the basis of three kinetic models including pseudo-first order, pseudo-second order and intraparticle diffusion. Isotherm equations including Langmuir, Freundlich and Dubinin-Radushkevich (D-R) were successfully applied to model the experimental data. An anionic resin loaded with DPKSH was used in a flow system for the in-line concentration of copper prior to spectrophotometric determination. Under optimized conditions, a linear response was observed between 20 and 80 mu g L-1, with limits of detection and quantification estimated at 0.5 and 1.8 mu g L-1, respectively, at the 95% confidence level with an enrichment factor of 11. The relative standard deviation was estimated to be 2.6% for 32 mu g L-1 Cu(II) (n = 20). The results obtained for copper determination in ethanol fuel samples agreed with those achieved by flame atomic absorption spectrometry (F AAS) at the 99% confidence level.