A Method to Evaluate Lipid Peroxidation by an Automated Analysis of Exhaled Pentane in Human and Rat Breath

Abstract
Pentane has been shown to be a reliable index of lipid peroxidation in vivo. We describe a new method for measuring this hydrocarbon in both human subjects and experimental animals. After collection of the breath samples, pentane is trapped in an adsorptive trap containing graphitized carbon black, thermally desorbed in a backflush mode, concentrated by two-stage cryofocusing and assayed by a gas chromatograph equipped with a flame ionization detector. The minimum detectable quantity for pentane is 8 pmol and, because large volumes can be concentrated, the method provides a very low limit of detection. A run-to-run reproducibility inferior to +10% (coefficient of variation) is obtained and statistically significant increase of exhaled pentane is measured in patients with rheumatoid arthritis and CCl4-treated rats. The method allows a convenient collection of breath samples in both humans and rats, and efficient preconcentration, and an automated analysis of exhaled pentane.