BerlinTrap: A new cryogenic 22-pole ion trap spectrometer

This research paper introduces and details the design and applications of a novel tandem mass spectrometer, named BerlinTrap. This apparatus integrates an electrospray ion source, a quadrupole mass spectrometer, a cryogenic 22-pole ion trap (ranging from 4 to 300 K), and an orthogonal reflectron time-of-flight mass spectrometer. The ions trapped within are cooled using helium as a buffer gas. The paper showcases the apparatus’s capabilities by examining the formation and solvation shell structure of weakly-bound He_nH₃O⁺ complexes and the electronic photodissociation spectrum of protonated tyrosine. The results indicate a vibrational temperature below 20 K for protonated tyrosine. Furthermore, the electronic spectrum of isolated protonated lumichrome is presented, with its structure determined through quantum chemical calculations. The BerlinTrap proves its potential for spectroscopy and reactivity studies on both small and large (bio-)molecular ions and their clusters.