Real-time selective detection of 2-chloroethyl ethyl sulfide (2-CEES) using an Al-doped ZnO quantum dot sensor coupled with a packed column for gas chromatography

We report a new portable chemical warfare agent analyzer for miniaturized gas chromatography (mini-GC), comprising a packed column and hydrothermally synthesized Al-doped ZnO quantum dots (AZO QDs). This device uses a small volume of the target gas (1 ml) without pre-concentration and can be used to detect 2-chloroethyl ethyl sulfide (2-CEES) gas, which is a mustard gas simulant, over a wide concentration range. The AZO QD (˜5 nm) sensor exhibited an outstanding sensing response (R) of 5,393 in detecting 20 ppm of 2-CEES; this performance is superior to those of other previously reported 2-CEES sensors based on semiconducting metal oxides. By optimizing the length of the packed column, we successfully decreased the retention time of 2-CEES to ˜150 s. More importantly, the manufactured mini-GC device can be used to selectively detect a small amount of target gas from other gases such as NH₃, NO, and CO. We demonstrated the excellent detection performance of the device for the real-time selective detection of 2-CEES.