Consecutive Infrared Multiphoton Dissociations in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

详细信息    查看全文

• 作者：D. Scott Tonner and Terrance B. McMahon
• 刊名：Analytical Chemistry
• 出版年：1997
• 出版时间：December 1, 1997
• 年：1997
• 卷：69
• 期：23
• 页码：4735 - 4740
• 全文大小：132K
• 年卷期：v.69,no.23(December 1, 1997)
• ISSN：1520-6882

文摘

Consecutive infrared multiphoton dissociations (IRMPD)may be observed in a Fourier transform ion cyclotronresonance mass spectrometer (FTICR). This is the IRMPD equivalent of previous MSⁿ experiments usingCID.This work presents a versatile technique, using abistableshutter to gate ON and OFF a continuous-wave (CW)CO₂laser for multiple irradiation periods of 0.1-1000 sduration. Consecutive photodissociations, up to MS⁴,aredemonstrated for the proton-bound dimer of diethyl etherand the resulting fragment ions. The photoproductsareformed close to the center of the FTICR cell, resulting inhigh product ion recovery efficiency. This differsfromCID products, which are formed throughout the FTICRcell causing reisolation/detection problems. The fragmentation resulting from the use of low-intensity, CW,infrared laser radiation is shown to be much more energyselective than CID. Photodissociation ofC₂H₅OH₂⁺ionproduces the lowest energy product ion exclusively, eventhough the two product channels differ only by ~5 kcal/mol. Low-energy CID, however, produces a mixture ofC₂H₅⁺ andH₃O⁺ products in the ratio of 1.3:1.Hence,the higher energy pathway(C₂H₅⁺) is substantiallyfavored. The current results indicate that this IRMPDMSⁿtechnique may be successfully applied to large biomolecules prepared by electrospray or MALDI.