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 presente d and differs from other configurations in that the enhancement source is introduced as an aerosol into a flame ionization detector (FID) ra ther than as a stationary solid bead positioned above a FID flame. Thi s aerosol enters the detector as a hydrogen flame located perpendicula r to the FID jet. Because the present design permits a constant and fr esh supply of alkali salt to reach the detector, detector response doe s not fatigue over time. This AFID design also allows for operation as a FID by implementing a simple pneumatic procedure. This paper will d eal with the performance and optimization of the detector in the phosp horous mode. The linear range for triethylphosphate exceeds four order s of magnitude. Selectivity ratios are in the four orders of magnitude range and detection limits for organophosphorus compounds studied ran ged from 2.38 to 14.2 pg P/s.