Carboplatin is widely used in pediatric oncology to treat different tumors. Aim of the present study was to assess the potential of sector field inductively coupled plasma mass spectrometry (SF-ICPMS) in evaluating the area under the plasma platinum concentration vs time curve in pediatric patients presenting solid tumors and treated with carboplatin 349-1000 mg m-2. Seventeen patients were enrolled and 23 courses of chemotherapy were evaluated. Plasma was ultrafiltered and free carboplatin was measured in ultrafiltrates as platinum by SF-ICP-MS. Comparison was made between different equations to obtain a target AUC. Limits of detection and of quantification, intra- and inter-day repeatability of the measurements, recovery of the 'free-carboplatin' confirmed SF-ICP-MS as a reliable technique in the quantification of serum platinum in anticancer carboplatin-based therapies.