GC/MS with Post-Column Switching for Large Volume Injection of Headspace Samples: Sensitive Determination of Volatile Organic Compounds in Human Whole Blood and Urine

摘要

ABSTRACT: When volatile or semivolatile compounds arenmeasured by headspace (HS) gas chromatography (GC)mass spectrometry (MS), the maximum gas volume to beninjected is usually 0.5-1.0 mL; over the volume, the MSndetector automatically shuts down due to impairment of thenvacuum rate of theMS ionization chamber. To overcome thenproblem, we modified the gas flow routes of a new type ofnGC/MS instrument to create a postcolumn switching sys-ntem, which can eliminate the large volume of gas beforenintroduction of target compounds into the MS ionizationnchamber. Our HS-GC/MS system enabled injection of asnlarge as 5 mL of HS gas without any disturbance. As the firstnexample analysis, we tried to establish the analysis ofnnaphthalene and p-dichlorobenzene in human whole bloodnand urine by this method with large volume injection. Thenlimits of detection for both compounds in whole blood andnurine were as low as about 10 and 5 pg/mL, respectively. The validation data and actualmeasurements were also demonstrated. Thennew GC/MS systemhas great potential to analyze any type of volatile or semivolatile organic compounds in biologicalmatrixes withnvery high sensitivity and full automation.