Onsite Analysis of Complex Samples Using Miniature Mass Spectrometry With Direct Sampling and Ionization

Miniature mass spectrometry (mini-MS) is a powerful method for onsite analysis of complex. The onsite sampling/ionization approach is critical in rapid screening of complex samples by mini-MS in field environments. Therefore, new development of direct ionization/sampling method coupled with mini-MS is needed for direct sample analysis. A direct sampling/ionization kit using wooden tip or plant tissue was developed to couple with mini-MS for onsite analysis of complex samples. Targeted analytes were detected and identified by mini-MS/MS.

Without complex hardware modification, direct coupling mini-MS with ESI kit technique using wooden tips or plant tissue has been demonstrated for onsite analysis of different raw samples. The sampling of the new method is relatively simple.The porous nature of wood allows effective loading sample to generate spray ionization and thus acquisition of durable ion signals. The slim and hard properties of wooden tips also allow to insert into specific locations of bulk biological tissue. Like wooden tip, plant tissue could also perform as ESI emitter to detect the compounds. Indeed, like WT-ESI coupled to benchtop MS, the ionization efficiency of WT-ESI would be lower than capillary ESI meths such as nano-ESI and PCSI. The direct ionization of raw samples using wooden tip or tissue is very sim-ple, cheap, and disposable. This method was applicable for direct analysis of raw liquid, powder, viscous, and bulk biological tissue under onsite field environments, indicating the potential applications in many fields including food safety, drug analysis,and forensic investigation.