Preconcentration/Separation of Gold and Palladium by a Microcolumn Packed with Azadirachta Indica Leaf Powder and Their Determination in Geological Samples by ICP-OES

A new method using a microcolumn (20 mm length x 2.0 mm i.d.) packed with Azadirachta Indica leaf powder (Neem leaf) as an adsorbent for the preconcentration/separation of Au and Pd prior to their determination by ICP-OES in geological samples is presented. Various factors affecting the separation and preconcentration of the target analytes such as pH, sample flow rate and volume, eluent concentration and volume and interfering ions were studied and the optimal experimental conditions were established. The adsorption capacity of Azadirachta Indica leaf for Au and Pd was found to be 39.2 and 9.8 mg g-1, respectively. The detection limits (3s) of this method for Au and Pd with an enrichment factor of 50 were 47 ng l-1 and 59 ng l-1 and the relative standard deviations were 4.8% and 5.7% (n = 7, adsorption capacity C = 5 ng ml-1), respectively. In order to validate the proposed method, the certified reference material, GBW07293, was analysed, and a good agreement was obtained between the certified and determined values.