Development and validation of an ICP-MS method for quantification of total carbon and platinum in cell samples and comparison of open-vessel and microwave-assisted acid digestion methods.

Cisplatin is a widely used chemotherapeutic drug. Due to severe side effects and intrinsic or acquired resistance, there is a great interest in developing new platinum-based anticancer agents and a need for robust and validated analytical methods for determination of platinum accumulation in biological samples. A validated ICP-MS method for quantification of total carbon and platinum in cell samples is presented, applicable for cellular drug accumulation studies of platinum-based drugs, enabling estimation of drug accumulation while simultaneously determining carbon to monitor the sample digestion efficiency. Adequate precision (RSD <6%), accuracy and sensitivity were achieved for carbon and platinum determinations. Limits of detection were 0.9-3.0 mg/L for carbon and 0.11-0.50 µg/L for platinum. Determination of platinum by ICP-MS in cell samples digested applying either open-vessel or microwave-assisted acid digestion produced similar concentrations, although the residual carbon content in the sample solutions were significantly higher following open-vessel acid digestion compared to microwave-assisted acid digestion. Experiments showed that the residual carbon content after acid digestion did not have an influence on determination of total platinum by ICP-MS.