Design and Application of A Novel Photo Ionization Detector
Mounted the self-made photo ionization detector(PID) on a GC,the instrument could complete the fast determination of environmental contaminants such as BTEX(benzene,toluent,ethylbenzene,xylene) and aldehydes without complex pretreatment.This paper introduced its basic principle,described the structure,the electronic system and results of the application.The spray nozzle and electrode were first designed as the whole,which minimized the volume of ionization chamber to 30 μL and largely improved the sensitivity of the detector.Meanwhile,the detector was easy to assemble.The precise amplifier AD549 was selected to meet the requirements of low noise and low baseline drift,as a result,excellent signal to noise ratio and stable signal output were obtained.The lamp of Kr was selected as ionization source and the standard gas of benzene(0.9×10-6 mol/mol) was chosen as test sample.The detection limit was below1×10-13 g/mL and the quantitative repeatability was particularly good with the relative standard deviation of 1.2%.