Anal. Chem. 2003, 75, 420-425
Collision-Activated Infrared Multiphoton Dissociation in a Quadrupole Ion Trap Mass Spectrometer Yuichiro Hashimoto,* Hideki Hasegawa, Kiyomi Yoshinari, and Izumi Waki
Central Research Laboratory, Hitachi, Ltd., Tokyo, Japan, and Hitachi Research Laboratory, Hitachi, Ltd., Ibaraki, Japan
We propose and demonstrate a new method for multiplestage mass spectrometry (MSn), collision-activated infrared multiphoton dissociation (CA-IRMPD), which is very effective for the quadrupole ion trap mass spectrometer (QITMS). CA-IRMPD uses a combination of focused laser irradiation (beam radius, ∼0.4 mm) and collisional activation by a supplemental AC voltage between endcap electrodes. This combination enables IRMPD, which has conventionally been ineffective above 10-4 Torr, to be used under a standard bath gas pressure of 2-8 mTorr. CA-IRMPD can produce richer spectra of product ions than CID or IRMPD while maintaining high sensitivity and mass resolution; thus, it will contribute to an accurate determination of peptide sequences.
between the endcap electrodes. Dehmelt potential depth in the z direction, Dz, is given by eq 1 at qz < 0.4 for r02 ) 2z02. 2,3,11
Multiple stage mass spectrometry is commonly used in biological and environmental analysis. In particular, quadrupole ion trap mass spectrometers (QITMS) have advantages of MSn (n g 2) and high sensitivity.1-10 Collision-induced dissociation (CID) is the most common method for MSn analysis in QITMS. 6-10 CID can be achieved by applying a supplemental AC voltage between endcap electrodes, with which ions are accelerated and activated by collision with the bath gas in the QITMS. Though CID has the advantage of low cost and simplicity, the product ions whose m/z is
