New Strategy for Further Improving the Detection Sensitivity of Direct Analysis in Real Time-Mass Spectrometry

Ambient mass spectrometry facilitates surface detection under ambient conditions and has quickly found its applications in various areas. However, the sensitivity of AMS methods is usually not as good as that of encapsulated ion sources due to less efficient ion transmission. In this work, a briefly machined external ion funnel (three-pole electrostatic lens) was adopted and installed between direct analysis in real time and the mass spectrometer inlet to increase detection sensitivity. Software investigation with SIMION version 8.0 was employed to calculate electric fields and to simulate the trajectories of charged particles in the electric field. Both the geometrical parameters of the ion funnel and the electric parameters were studied to obtain the optimal ion focusing results, which demonstrated the ion funnel equipment would greatly improve the ion transmission efficiency. The equipment showed good prospect in direct analysis in real time-mass spectrometry analysis in the future.