Quantification of Ultra-Trace Lead in Water After Preconcentration on Nano-Titanium Oxide Using the Slurry Sampling ETAAS Method.

A simple and efficient dispersive micro solid-phase extraction (DMSPE) method using nano-TiO as a sorbent was developed for the separation and preconcentration of (ultra) trace levels of lead in water samples prior to quantification by electrothermal atomic absorption spectrometry (ETAAS). Key experimental parameters affecting the DMSPE process, including pH, ionic strength, sorbent dosage, and preconcentration factor, were optimized. The optimized method demonstrated a preconcentration factor of 20, a relative standard deviation below 4.5%, and a detection limit of 0.11 µg/L. The procedure was validated using certified reference material (CRM TM-25.5) and applied to real water samples from a lake, a residential well, and industrial wastewater. Satisfactory recoveries (89-103%) confirmed the reliability of the method for the determination of low lead concentrations in complex matrices.