The sequence analysis of peptides was performed by nano-electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry（Nano-ESI-FT-ICR-MSn） and several peptides were chosen as examples. W...The sequence analysis of peptides was performed by nano-electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry（Nano-ESI-FT-ICR-MSn） and several peptides were chosen as examples. With the aid of the collision induced dissociation（CID）, FT-ICR provides not only precise mass/charge ratio, but also structure information of the selected peptides. The fragment ions were identified according to the observed molecular weights and peptide sequence was determined successfully. So Nano-ESI-FT-ICR-MSn is a useful tool for identification of the amino acid sequence of peptides with high confidence. Besides, a pathway for the dehydration of y ions without amino acids containing carboxylic acid under sustained off-resonance irradiation collision-induced dissociation（SORI-CID） condition was proposed.展开更多
This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of ...This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of Xe-can be prepared through method of four-photon resonant excitation by dye laser with wavelength of -440 nm. Absorption of an additional photon （the transfer laser） of the same wavelength will complete the laser induced collisional ionization process. The resonance enhanced ionization spectrum of Xe by four laser photons at -440nm is measured through time-of-flight mass spectrometry, this aims at the preparation of the initial state of the system proposed. The Stark broadening of the measured spectrum is observed and consistent with the previous study. Analysis of the measured resonance ionization spectrum implies the feasibility of -440 nm four-photon resonant excitation of the initial 4f state of the Xe Kr system proposed in this paper, which prepares for a further experiment of laser induced collisional ionization.展开更多
Technique of lutetium isotopic analysis by laser resonance ionization mass spectrometry(LRIMS) was developed in the presence of isobaric interference. In the case of real sample, the elemental selectivity was better t...Technique of lutetium isotopic analysis by laser resonance ionization mass spectrometry(LRIMS) was developed in the presence of isobaric interference. In the case of real sample, the elemental selectivity was better than 8×105, and the detection efficiency was 8.3×10-5. The technique of wavelength scanning method was set up in order that the accurate isotopic ratio could be determined. And the numerical computational method was provided to calculate the correct factor of isotopic ratio. Using this technique, the isotopic ratio measured by LRIMS is in good agreement with standard value measured by TIMS.展开更多
基金Supported by the National Natural Science Foundation of China(No.20675079)
文摘The sequence analysis of peptides was performed by nano-electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry（Nano-ESI-FT-ICR-MSn） and several peptides were chosen as examples. With the aid of the collision induced dissociation（CID）, FT-ICR provides not only precise mass/charge ratio, but also structure information of the selected peptides. The fragment ions were identified according to the observed molecular weights and peptide sequence was determined successfully. So Nano-ESI-FT-ICR-MSn is a useful tool for identification of the amino acid sequence of peptides with high confidence. Besides, a pathway for the dehydration of y ions without amino acids containing carboxylic acid under sustained off-resonance irradiation collision-induced dissociation（SORI-CID） condition was proposed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10674036 and 10774033)Program for New Century Excellent Talents in UniversityProgram of Excellent Team in Harbin Institute of Technology
文摘This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of Xe-can be prepared through method of four-photon resonant excitation by dye laser with wavelength of -440 nm. Absorption of an additional photon （the transfer laser） of the same wavelength will complete the laser induced collisional ionization process. The resonance enhanced ionization spectrum of Xe by four laser photons at -440nm is measured through time-of-flight mass spectrometry, this aims at the preparation of the initial state of the system proposed. The Stark broadening of the measured spectrum is observed and consistent with the previous study. Analysis of the measured resonance ionization spectrum implies the feasibility of -440 nm four-photon resonant excitation of the initial 4f state of the Xe Kr system proposed in this paper, which prepares for a further experiment of laser induced collisional ionization.
文摘Technique of lutetium isotopic analysis by laser resonance ionization mass spectrometry(LRIMS) was developed in the presence of isobaric interference. In the case of real sample, the elemental selectivity was better than 8×105, and the detection efficiency was 8.3×10-5. The technique of wavelength scanning method was set up in order that the accurate isotopic ratio could be determined. And the numerical computational method was provided to calculate the correct factor of isotopic ratio. Using this technique, the isotopic ratio measured by LRIMS is in good agreement with standard value measured by TIMS.
