Rapid determination of platinum plasma concentrations of chemotherapy patients using total reflection X-ray fluorescence

A fast and simple method using Total Reflection X-ray Fluorescence has been developed for the determination of platinum plasma concentrations of patients undergoing chemotherapy with Pt-bearing drugs. Avoiding chemical digestion, micro liter amounts of blood plasma are employed using Compton peak standardization and the use of matrix-matched spiked samples with known amounts of platinum for spectrometer sensitivity determination. The analytical results with the proposed procedure are compared to values obtained with Graphite Furnace Atomic Absorption Spectrometry obtaining values of comparable accuracy and precision. Measurements of the time course of the Pt plasma concentration in single-dose treatments, and of the achieved plasma concentration of multiple infusion treatments demonstrate the potential usefulness of the method for pharmacokinetic studies or for routine optimization of Pt chemotherapy treatments.