An improved photoionization detector with a micro gas chromatography column for portable rapid gas chromatography system

An improved portable photoionization detector (PID) was proposed in this manuscript. A novel structure named “nozzle” with a volume slightly less than the ionization chamber was positioned in the center of the chamber, dramatically reducing the ionization chamber volume and improving device sensitivity. An annular accelerating electrode was embedded in the nozzle groove to shield from vacuum ultraviolet (VUV) light radiation, decreasing background noises. Then the improved PID combined with a high separation efficiently micro gas chromatography (GC) column was used to construct a portable rapid GC system. The results indicated that the proposed PID in this study demonstrated an ultra low background noise (≤1 × 10−14 A) and a small baseline drift. Moreover, the proposed PID was characterized with a response time less than 30 ms and a large linear range of 106. The proposed system was used to detect gas mixtures with a detection limit less than 5 ppb.