Determination of perfluorodecalin and perfluoro-N-methylcyclohexylpiperidine in rat blood by gas chromatography-mass spectrometry.
A gas chromatography-mass spectrometry method (SIM mode) was developed for the determination of perfluorodecalin (cis and trans isomers, 50% each) (FDC), and perfluoromethylcyclohexylpiperidine (3 isomers) (FMCP) in rat blood. The chromatographic separation was performed by injection in the split mode using a CP-select 624 CB capillary column. Analysis was performed by electronic impact ionization. The ions m/z 293 and m/z 181 were selected to quantify FDC and FMCP due to their abundance and to their specificity, respectively. The ion m/z 295 was selected to monitor internal standard. Before extraction, blood samples were stored at -30 degrees C for at least 24 h in order to break the emulsion. The sample preparation procedure involved sample clean-up by liquid-liquid extraction. The bis(F-butyl)ethene was used as the internal standard. For each perfluorochemical compound multiple peaks were observed. The observed retention times were 1.78 and 1.87 min for FDC, and 2.28, 2.34, 2.48 and 2.56 min for FMCP. For each compound, two calibration curves were used; assays showed good linearity in the range 0.0195-0.78 and 0.78-7.8 mg/ml for FDC, and 0.00975-0.39 and 0.39-3.9 mg/ml for FMCP. Recoveries were 90 and 82% for the two compounds, respectively with a coefficient of variation <8%. Precision ranged from 0.07 to 15.6%, and accuracy was between 89.5 and 111.4%. The limits of quantification were 13 and 9 microg/ml for FDC and FMCP, respectively. This method has been used to determine the pharmacokinetic profile of these two perfluorochemical compounds in blood following administration of 1.3 g of FDC and 0.65 g of FMCP per kg body weight, in emulsion form, in rat.