ALKALI FLAME IONIZATION DETECTOR FOR GAS-CHROMATOGRAPHY USING AN ALKALI SALT AEROSOL AS THE ENHANCEMENT SOURCE

A new design of an alkali flame ionization detector (AFID) is presented and differs from other configurations in that the enhancement source is introduced as an aerosol into a flame ionization detector (FID) rather than as a stationary solid bead positioned above a FID flame. This aerosol enters the detector as a hydrogen flame located perpendicular to the FID jet. Because the present design permits a constant and fresh supply of alkali salt to reach the detector, detector response does not fatigue over time. This AFID design also allows for operation as a FID by implementing a simple pneumatic procedure. This paper will deal with the performance and optimization of the detector in the phosphorous mode. The linear range for triethylphosphate exceeds four orders of magnitude. Selectivity ratios are in the four orders of magnitude range and detection limits for organophosphorus compounds studied ranged from 2.38 to 14.2 pg P/s.