Solid Phase Extraction of Pb²? and Cd²? from Tigris River Water Using an AmideFunctionalized Silica Sorbent and ICP-OES Determination

In this study, the preconcentration, separation, and simultaneous determination of Pb²? and Cd²? ions in water samples were carried out using solid-phase extraction with a silica-gel–based mixed-mode HPLC stationary phase synthesized in our previous work. This phase had previously shown strong performance in separating various polar and nonpolar compounds, prompting its evaluation for metal ion enrichment. Solutions containing Pb²? and Cd²? were passed through the column, eluted with 7 mL of 1 mol L?¹ HNO?, and analyzed by ICP-OES. Parameters such as pH, sorbent amount, eluent type and volume, flow rates, sample volume, and foreign ion effects were examined. The optimum pH was found to be 6, with detection limits of 0.15 µg L?¹ for Pb and 0.1 µg L?¹ for Cd. The enrichment factor was 71.4 for both ions. The method was validated using NIST 1643e and successfully applied to Dicle River water samples.