Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521784
Title: Development of a novel, long-lifetime supersonic jet source for laser spectroscopy of biological molecules
Author: Taherkhani, Mehran
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2010
Availability of Full Text:
Access from EThOS:
Access from Institution:
Abstract:
A novel laser desorption system, with improved signal stability and extraordinary long lifetime, is presented for the study of jet cooled biomolecules in the gas phase using vibrationally resolved photoionisation spectroscopy. Tryptophan (Trp) is used as the test substance to characterize this desorption source. Here, the surface of a moving and rotating rod (graphite/Trp, 3mm diameter and 6 mm length) is exposed to a pulsed desorption beam from a Nd:YAG (1064 nm) laser running at 20Hz (Continuum Minilite).The characteristics of the source developed here and its properties with respect to cooling and stability have been investigated. Good control over the rod movement and the delivery of the IR beam result in a highly stabilized source with no noticeable fragmentation products.The combination of premixing within the source and using a pellet has made it possible to produce a stable jet-cooled beam of Trp, which lasts for several weeks without changing the sample. Additionally, the stability and signal to noise ratio has been improved by averaging the signal over the entire sample pellet by synchronizing the data acquisition with the rotation of the sample rod. The results demonstrate how a combination of the above helps to produce stable time of flight (TOF) signal and good quality one- and two-colour resonant two-photon ionisation (R2PI), photoionisation efficiency (PIE) and mass analyzed threshold ionization (MATI) spectra of Trp. The existence of six low-lying conformers of Trp in the gas phase has been confirmed. The first MATI spectrum of an isolated biomolecule (Trp) via R2PI for the determination of IE with high accuracy as ± 3 cm-1 has been recorded.
Supervisor: Muller-Dethlefs, Klaus Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.521784  DOI: Not available
Keywords: Laser desorption, Spectroscopy, Biomolecules
Share: