Development of Tandem Ion Mobility Spectrometry Based on Heat-Induced Dissociation and Its Application in Explosives Detection

Ion mobility spectrometry (IMS) serves as a crucial analytical technique and has been extensively applied to the analysis of hazardous explosives. However, the detection of ions with the same or similar mobility remains a significant challenge for IMS. Just as tandem mass spectrometry plays a crucial role in analysis, the development of tandem ion mobility spectrometry has also greatly enhanced the qualitative capabilities; ion dissociation technology is one of the key components. This study creatively introduces a heat-induced dissociation (HID) technique and develops a HID module for ion dissociation. Primarily, the HID module was integrated into a homemade ion trap mass spectrometer to validate the feasibility of the HID technology. Subsequently, the thermal field distribution of the HID module was simulated, thereby highlighting the significance of the temperature in the dissociation process. Finally, a tandem drift tube ion mobility spectrometry (DTIMS) detection system incorporating a HID module was established. Five representative explosive samples were selected to validate the feasibility of the tandem DTIMS. Both atmospheric pressure dissociation mass spectra and mobility spectra were obtained, and their dissociation products were analyzed through comparison with collision-induced dissociation (CID). The results demonstrate that incorporating HID technology into the tandem DTIMS system enables ion dissociation and the acquisition of atmospheric pressure second-order ion mobility spectra. The combination of fragment peak information enhances the qualitative capabilities of ion mobility spectrometry. This advancement is anticipated to reduce the probability of false positives in future applications, thereby improving the accuracy and reliability of the system. This study provides critical technical support for explosive detection in the field of public safety.