A method using automated on-line solid-phase extraction (SPE) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) for the determination of 8-iso-PGF2α in human exhaled breath condensate (EBC) was developed and validated. A C18 SPE column with an affinity sorbent was used for on-line extraction. A C18 column was employed for LC separation and ESI-MS/MS was utilized for detection. 8-iso-PGF2α-d<sub>4</sub> was used as an internal standard for quantitative determination. The extraction, cleanup and analysis procedures were controlled by a fully automated six-port switch valve. Identification and quantification were based on the following transitions: m/z 353 → 193 for 8-iso-PGF2α and m/z 357 → 197 for 8-iso-PGF2α-d<sub>4</sub>, respectively. Good recoveries from 98.94 to 99.86% were measured and satisfactory linear ranges for these analytical compounds were determined. Intra-day and inter-day precision showed that coefficients of variance (CV) ranged from 6.5 to 8.0% and 5.2 to 6.3%, respectively. The applicability of this newly developed method was demonstrated by analyzing human EBC samples for an evaluation of the future risk of human exposure to nanoparticles.
