Simple analysis of naphthalene in human whole blood and urine by headspace capillary gas chromatography with large volume injection

Naphthalene is still being sold as a moth repellant; there is a possibility that accidental ingestion of such a product by a small infant causes serious poisoning. In this communication, a very simple method for analysis of naphthalene in human whole blood and urine by headspace gas chromatography (GC) has been presented. It neither needs solid-phase microextraction nor cryogenic trapping devices, but needs only a conventional capillary GC instrument with flame ionization detection. The advantage of the method is that as large as 5 ml of headspace vapor can be injected into a GC instrument in the splitless mode for sensitive detection. After heating a diluted whole blood or urine sample containing naphthalene and 1-methylnaphthalene (internal standard, IS) in a 7.0 ml vial at 80℃ for 30 min, 5 ml of the headspace vapor was drawn with a glass syringe and injected into the gas chromatograph. Before injection, the column was set at 50℃ to trap the analytes, and then the oven temperature was programmed up to 300℃. Sharp peaks were obtained for both analyte and IS, and only a few impurity peaks, which did not interfered with the test peaks, appeared especially for whole blood samples. The detection limits (signal-to-noise ratio ≧ 3) were about 0.05 and 0.01 μg/ml for whole blood and urine, respectively. Precision and linearity were also examined to confirm the reliability. Such a simple headspace GC technique with large volume injection can be probably applied also to other low-volatile compounds in biological matrices, and will be useful in forensic toxicological analysis