A pulsed pinhole atmospheric pressure interface for simplified mass spectrometry instrumentation with enhanced sensitivity

Rationale A proof-of-concept pulsed pinhole atmospheric pressure interface, namely PP-API, was developed and characterized for mass spectrometry instrumentation. Methods The PP-API was analyzed and optimized theoretically with respect to gas flow rate, opening force and dimensions. A PP-API interfaced mass spectrometry system was then constructed and tested. Results As a discontinuous pressure interface, the PP-API allows efficient ion transfer from atmosphere pressure ionization sources to ion traps directly. Both nano-ESI and APCI ionization sources have been successfully integrated with the PP-API interface for the detection of volatile, organic, peptide and polymer samples. The use of multiple ionization sources has also been demonstrated to enhance signal intensity, as well as avoid charge competitions in ionization sources. Conclusions With simplified geometry and high ion transfer efficiency, this PP-API would enable miniaturized mass spectrometry systems with high sensitivity.