5853

5468

كارشناسي ارشد

شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده شيمي

1389

شانزده،140ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمود تيريزچي

10/2/90

يوسف غايب، فرهاد حدادزاده

شيمي

ID5468

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Abstract Different reactant ions including CH5 NH4 NO and H3O have been used in soft ionization Among those NO NH4 and H3O do not react with air components but react very fast with major inorganic compounds H3O which ionizes compounds via proton transfer reaction is the major reactant ion in ion mobility spectrometry IMS In this work a method has been introduced to produce NO as the major reactant ion in IMS Having two independent reactant ions NO and H3O gives the possibility of detection of more compounds In addition when two compounds have similar spectrum with H3O they may be distinguish by use of NO reactant ion Unlike the H3O humidity has minimum effect on NO chemistry so that NO is the best reactant ion in the presence of humidity NO is slightly produced in corona discharge when oxygen presents Although the abundance of NO produced in the corona discharge increased with temperature voltage and the oxygen content at the highest value its peak has lower intensity than that of H3O So several other methods such as the reaction between nitric acid and cupper or sulfuric acid and sodium nitrite were tried produce NO The best method was found to be the use of arc in air In addition a disk was used in the front of the needle to prevent entering sample to the corona region Hence the product ions were purely due to the reaction between NO and sample After successful production of NO ion mobility spectra of aromatics narcotics explosives and thiols were separately recorded with both NO and H3O reactant ions Comparison of IMS spectra showed that the major peaks for a substance with two reactant ions are different In the case of NO ions were mainly in the form of M or M NO while for the case of H3O they are MH In some cases like benzene the use of NO gave more sensitivity Key Words Ion Mobility Spectrometry Reactant ion NO H3O Charge transfer Proton transfer

محمود تيريزچي

يوسف غايب، فرهاد حدادزاده