Development and validation of a high- throughput method for the determination of titanium dioxide in rodent lung and lung-associated lymph node tissues
There is a need to determine the tissue burdens of inhaled titanium dioxide due to the widespread industrial use of this compound. A high-throughput method for the determination of TiO2 as titanium in rodent lung and lung-associated lymph node tissues by inductively coupled plasma optical emission spectrometry (ICP-OES) was developed and validated. Samples were digested in open-vessel, disposable centrifuge tubes in the presence of nitric and hydrofluoric acids. The determined method quantitation limit (MQL) was 4.2 µg TiO2/g tissue. Replicate control samples prepared at this level were determined with a high level of accuracy (100%) and precision (2% RSD). After validation, the described method was applied to determine the concentration of TiO2 (as titanium) in 600 rodent tissue samples spanning a 16-month time period. During this time period, laboratory control samples (n = 48) were analyzed to assess the long-term precision and accuracy of the method. The average recovery of titanium in these samples was 102±4.8%.