Method development for the measurement of quinone levels in urine.

A method was developed for the quantification of 1-4 ring quinones in urine samples using liquid-liquid extraction followed by analysis with gas chromatography-mass spectrometry. Detection limits for the ten quinones analyzed are in the range 1-2 nmol dm(-3). The potential use of this approach to monitor urinary quinone levels was then evaluated in urine samples from both Sprague-Dawley rats and human subjects. Rats were exposed to 9,10-phenanthraquinone (PQ) by both injection and ingestion (mixed with solid food and dissolved in drinking water). Urinary levels of PQ were found to increase by up to a factor of ten compared to control samples, and the levels were found to depend on both the dose and duration of exposure. Samples were also collected and analyzed periodically from human subjects over the course of six months. Eight quinones were detected in the samples, with levels varying from below the detection limit up to 3 µmol dm(-3).

Aerosol-borne quinones and reactive oxygen species generation by particulate matter extracts.

The mass loadings of quinones and their ability to generate reactive oxygen species (ROS) were investigated in total suspended particulate samples collected in Fresno, CA, over a 12-month period. Particles were collected on Teflon filters and were analyzed for the presence of 12 quinones containing one to four aromatic rings by gas chromatography with mass spectrometry. Measured levels are generally greater than mass loadings reported at other locations. The mass loadings were highest during winter months and were strongly anticorrelated with temperature. ROS generation was investigated by measuring the rate of hydrogen peroxide production from the reaction of laboratory standards and ambient samples with dithiothreitol (DTT). ROS generation from ambient samples shows a strong positive correlation with the mass loadings of the three most reactive quinones and may account for all of the ROS formed in the DTT test.