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We have designed and constructed a linear quadrupole ion trap for the measurement of laser-induced fluorescence (LIF) of mass selected gas-phase ions produced by electrospray ionization. The instrument consists of a simple electrospray source, radiofrequency octopole guide, a dc quadrupole bender, a quadrupole mass filter, the linear quadrupole trap (which is equipped with optics for LIF collection and a channeltron ion detector), and several multielement focusing lenses. With this instrument, the LIF decay lifetime of gas-phase Rhodamine 640 radical cations is determined for the first time.

An improved, high‐performance version of the concentric vacuum chamber design is shown for forming ions at high pressure in a strong magnetic field and detecting them in an adjacent Fourier transform ion cyclotron resonance mass spectrometry (FTICR) trapped ion cell. Improvements in system design, including primarily the addition of a mechanical shutter to halt the flow of neutrals to the trapped ion cell during FTICR detection, allow a more than 100‐fold improvement in pressure drop between the source and analyzer chamber to be realized. Within a 20 cm distance, ions formed in an electrospray ion source at atmosphere are transported across five concentric tube conductance limits to a trapped ion cell at a shuttered pressure below 2×10−9 Torr. High resolution detection of electrosprayed proteins is demonstrated and, for example, mass resolutions of 1×105 for the +14 charge state of horse heart myoglobin (at m/z 1211) and 2×105 for +5 charge state of bovine insulin (at m/z 1147) are obtained. The original advantages of the concentric tube vacuum chamber are retained. Forming the ions within the magnetic field permits a 40‐fold enhancement in sensitivity to be obtained. Narrow kinetic energy distributions are achieved because magnetic field confinement eliminates the need for complex electric focusing assemblies that exhibit mass discrimination and broaden the kinetic energy distribution. Finally, the shutter is demonstrated to serve effectively as an alternative to pulsed valve assemblies for the transient introduction of a collision gas to the trapped ion cell.

An external electron ionization (EI) source has been interfaced to a 7T Fourier transform ion cyclotron resonance mass spectrometer and tested for volatile complex mixture analysis. A new Sulfinert®-deactivated inlet system provides continuous stable sample flow to the EI source, leading to stable ion signal (±10% deviation) for 2h from a 200nL mixture of 15 n-alkylbenzenes. Ultrahigh-mass resolving power, m∕Δm50%≈735000, was obtained for 1-bromo-2-chlorobenzene with accurate isotopic ratio measurement. Base line resolution was observed for two of the closest commonly encountered mass doublets, C3∕SH4 (m2−m1=3.4mDa at m∕z=190) and SH3C13∕C4 (m2−m1=1.1mDa at m∕z=190). Although hydrocarbons dominate the positive-ion 18eV EI Fourier transform ion cyclotron resonance mass spectrum from diesel fuels, many sulfur-, nitrogen-, and oxygen-containing compounds were readily observed without prior fractionation. By comparing 18eV EI Fourier transform ion cyclotron resonance mass spectra of unprocessed and processed ...

A Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer has been installed at a free electron laser (FEL) facility to obtain infrared absorption spectra of gas phase ions by infrared multiple photon dissociation (IRMPD). The FEL provides continuously tunable infrared radiation over a broad range of the infrared spectrum, and the FT-ICR mass spectrometer, utilizing a 4.7Tesla superconducting magnet, permits facile formation, isolation, trapping, and high-mass resolution detection of a wide range of ion classes. A description of the instrumentation and experimental parameters for these experiments is presented along with preliminary IRMPD spectra of the singly-charged chromium-bound dimer of diethyl ether (Cr(C4H10O)2+) and the fluorene molecular ion (C13H10+). Also presented is a brief comparison of the fluorene cation spectrum obtained by the FT-ICR-FEL with an earlier spectrum recorded using a quadrupole ion trap (QIT).