Application of β-cyclodextrin in polymeric solid phase for separation and determination of lead in different environmental matrices

Immobilization of -cyclodextrin on Dowex resin as an insoluble polymeric matrix by covalent bond presents a new solid-phase medium for preconcentration of Pb (II) at trace level in environmental samples prior to its flame atomic absorption spectrometric determination. The method is based on the sorption of lead after passing on modified Dowex sorbent in a column. The effect of several parameters such as pH, flow rate of sample, eluent kind and volume was investigated. The sorption capacity of the matrix has been found to be 0.4996mgg(1) of adsorbent with the preconcentration factor of 250 for Pb (II). Nitric acid (3 M) as an eluent was sufficient to obtain quantitative recovery (>95%) for Pb (II). The optimum flow rate was 10mlmin (1). The calibration curve was linear in the range of (3250ngmL(1)) with a correlation coefficient of 0.9995. The limit of detection (LOD) based on three times the standard deviation of the blank was 1.37ngmL(1). The relative standard deviation (RSD) for determination of 10ngmL(1) and 100ngmL(1) of Pb (II) was 3.00 % and 0.58 % (n=10), respectively. The method was successfully applied to determination of lead in some environmental samples such as tap water, river water, soil and rice.