You are here:
HIGH-SPEED GC/MS FOR AIR ANALYSIS
Citation:
Berkley, R E., M. L. Akard, K. D. Oliver, H. H. Jacumin Jr., AND B. D. Gardner. HIGH-SPEED GC/MS FOR AIR ANALYSIS. Presented at Federation of Analytical Chemistry and Spectroscopy Societies, Detroit, MI, October 7-12, 2001.
Impact/Purpose:
This project is intended to provide the Agency with much faster methods of GCMS analysis without sacrificing data quality.
Description:
High speed or fast gas chromatography (FGC) consists of narrow bandwidth injection into a high-speed carrier gas stream passing through a short column leading to a fast detector. Many attempts have been made to demonstrate FGC, but until recently no practical method for routine analyses had been realized. Adequate columns have been available, but performing consistent narrow-bandwidth injections has been problematic. Also, few versatile detectors fast enough to trace narrow peaks have been available. We report here a procedure that performs analyses of EPA Method TO-14 target list compounds at a rate ten times faster than standard Method TO-14 with similar data quality.
A chromatofast GC Accelerator was used to perform injections into a 16m x 0.25 mm DB-1 column in an Agilent Technologies 6890 chromatograph equipped with fast temperature programming and pressure programming capability. A helium carrier flow rate of 5ml/min was used. The detector was a Leco Pegasus II time-of-flight mass spectrometer. The GC Accelerator cryotrapped the sample in an open tube which was then backflushed while being heated with a capacitive discharge at an estimated rate of 100,000C /s. The Pegasus II can record up to 500 full mass spectra per second but was operated at only 50 mass spectra per second. Chromatograms of 2min duration adequately separated all of the TO-14 target list compounds well enough that the Pegasus II data processing algorithm could correctly identify and quantitate them. Data processing was performed in the background during data acquisition.
Linearity of response to changing sample volumes and changing sample concentrations was demonstrated. A group of ambient air samples was analyzed repeatedly by both standard Method TO-14 and fast GCMS, and data from both methods were in close agreement.
This work has been funded wholly or in part by the United States Environmental Protection Agency under Contract No. 68D00206 to Man Tech Environmental Technology. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.