Title page for etd-0118116-185443


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URN etd-0118116-185443
Author Chun-Yi Chen
Author's Email Address No Public.
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Department Mechanical and Electro-Mechanical Engineering
Year 2015
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Dual Ion Source Composed of Helium Plasma and Electrospray Ionizations for Ambient Mass Spectrometry Detections
Date of Defense 2015-08-28
Page Count 71
Keyword
  • Atmospheric Plasma Ionization
  • Electrospray Ionization
  • Ambient Mass Spectrometry
  • Atmospheric Pressure Chemical Ionization
  • Dual Ion Source
  • Abstract This work develops an innovative symmetric coaxial dual ion source combining a balanced atmospheric helium plasma ion source and an electrospray ion source to simultaneously detect both polar and nonpolar chemical compounds. The traditional linear-type coaxial dual ion source suffers the drawback of floating voltage at the plasma outlet of the glass tube. When the dual ion source is working at dual ion source mode, the high floating voltage at the plasma outlet of the glass tube will interfere the ESI source which leads to unstable signals. In order to solve this problem, the balanced electrode design of the symmetric coaxial dual ion source was introduced to eliminate the floating voltage by changing the drive phase of the plasma generator. The results show that after 100 minutes of continuous testing in the dual source mode, the ESI source can constantly produce ions with the existence of plasma source due to the elimination of floating voltage and the dual source can provide more than 109 ion∙cm-3 ion intensity that can apply for most of the ambient mass spectrometry applications. In order to optimize the symmetric coaxial dual source’s stability and increase the total ion intensity, four important parameters including the geometric design of the plasma source and the ESI source, ESI spray voltage, the injection rate of ESI solutions, and the flow rate of helium as the carrier gas for producing plasma have been studied through the results of MS results and the pictures were taking by the digital microscope. Standards of volatile organic compounds, pesticide, cold syrup, Chinese herbal medicine, vitamins, tetradecane and hexadecane were used for testing in three different modes including plasma-only, ESI-only, and dual ion source modes. Results show that the developed dual source successfully detect the analytes and can both detect polar and nonpolar compounds which substantially improve the abilities of MS system. The developed system can apply in food safety testing, air pollution monitoring, and pharmaceutical composition analysis.
    Advisory Committee
  • Shin-Pon Ju - chair
  • Lung-Ming Fu - co-chair
  • Chan-Chiung Liu - co-chair
  • Chiun-Gung Juo - co-chair
  • Che-Hsin Lin - advisor
  • Files
  • etd-0118116-185443.pdf
  • Indicate in-campus at 99 year and off-campus access at 99 year.
    Date of Submission 2016-06-29

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