Gas chromatography with diode array detection in series with flame ionisation detection

Abstract

We introduce a gas chromatography detection approach that uses diode array detection operated in series with flame ionisation detection and demonstrate the utility of the detection approach for determination of volatile organic compounds. Diode array detection brings ultraviolet − visible spectroscopy (over a range of 190–640nm) onto the capillary gas chromatography time-scale, where average peak widths of analytes are on the order of 3–5s. The non-destructive nature of the diode array detector affords serially-coupled flame ionisation detection. This arrangement delivers near-simultaneous selective and universal detection without incurring additional analytical time, and without recourse to column flow splitting. The hyphenated technique is shown to be effective for chromatographic applications spanning an equivalent volatility range from C1 to C7n-paraffin hydrocarbons. The approach introduced herein provides increased sensitivity and selectivity for classes of compounds amenable to electronic spectroscopy such as alkenes, dienes, sulfurs, and aromatic compounds. The approach is demonstrated for direct measurement of carbon disulfide in work place atmospheres with a detection limit of 93pg on column and for the direct measurement of 1,3-butadiene in hydrocarbon matrices and ambient air with a detection of 73pg on column, each in less than 5min.