9018

8363

كارشناسي ارشد

شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده شيمي

1392

نه،69ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمود تبريزچي

حسين فرخ پور

20/3/93

حسن قاضي عسگر، محمد محسن مومني

شيمي

ID8363

Time of Flight Mass Spectrometry of Amino Acids by the New Laser Method a Feasibility Study Nafiseh Panahi Esfahani panahi es@yahoo com 21 January 2014 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 I R Iran Degree M Sc Language Farsi Mahmoud Tabrizchi m tabriz@cc iut ac ir Hossein Farrokhpour h farrokh@cc iut ac ir Abstract Time of flight mass spectrometry is one of the most sensitive and widely used methods for material analysis In TOF MS molecules are ionized accelerated and separated in a field free region In fact ions of different m z are dispersed in time during their flight along a field free drift path of known length The lighter ones will arrive earlier at the detector than the heavier ones In this work the TOF MS constructed in Laser Laboratory of Isfahan University of Technology was used to record mass spectra of amino acids including phenylalanine alanine valine and proline An Nd YAG laser at first harmonic 1064 nm was used as a desorption ionization source The new method introduced in the laser laboratory of chemistry department of Isfahan University of Technology was used In this method laser is irradiated on the backside of a plate on which amino acid and an alkali salt is coated Because of no direct interaction between the laser light and sample little or no fragmentation was observed Laser energy on the backside of the plate causes the amino acid and alkali salt to evaporate and the alkali cation is attached to the amino acid molecules In this work firstly the mass spectrum of the blank plate Stainless Steel 0 1 mm thick was recorded Ions of K Cr Mn and Fe were observed and used for mass calibration In addition mass spectra of NaF and LiCl on the plate were separately recorded and ions of Na Na NaF Li and Li LiCl were observed Finally phenylalanine and sodium fluoride were loaded on the plate and mass spectrum was recorded in which M H 2Na was observed The experiment was tried with lithium chloride and better results were obtained It was concluded that lithium attaches better than sodium cation to amino acids Hence the mass spectra of phenylalanine alanine valine and proline with lithium chloride were recorded Similar ions as to MALDI like Amino Acid 2Li H were observed for all aminoacids Keyword Time of flight mass spectrometry Amino acid Laser ionization mass spectrometry

محمود تبريزچي

حسين فرخ پور

حسن قاضي عسگر، محمد محسن مومني