Although the miniaturization of mass spectrometry (MS) frequently compromises analytical performance due to size and power limitations, the direct on-site analysis of complex samples requires a miniature mass spectrometer (mini-MS) to have enhanced instrument capabilities. To resolve this challenge, we have developed our "Brick" mini-MS into a next-generation system incorporating a differential-pressure dual-trap configuration. Each trap functions at distinct pressures, enabling parallel and optimized operations: ion accumulation/cooling and dissociation at higher pressures, in conjunction with ion isolation and MS analysis at lower pressure. Efficient ion transfer between the two traps enables parallel ion manipulation and diverse fragmentation modes. The parallel ion accumulation mode boosted the sensitivity of the miniature instrument by ∼20-fold, down to 50 pg/mL. In addition to conventional in-trap collision induced dissociation (CID), transfer dissociation during the ion accelerating and shuttling process and high-pressure collisional dissociation (HpCD) in a higher-pressure trap were also investigated. The results demonstrate that HpCD can generate more extensive ion fragments, which are typically observed in beam-type collisional activation dissociation methods. This study significantly advances the capabilities of mini-MS for high-performance, field-deployable analytical applications.
Ma et al. (2025) studied this question.