Title page for ETD etd-51481373971961


Type of Document Dissertation
Author Combs, Michael T.
Author's Email Address mcombs@vt.edu
URN etd-51481373971961
Title Optimal Analysis of Sulfonamides From Biological Matrices Using Supercritical Fluids
Degree PhD
Department Chemistry
Advisory Committee
Advisor Name Title
Anderson, Mark R.
Castagnoli, Neal Jr.
Glanville, James O.
McNair, Harold M.
Taylor, Larry L. Committee Chair
Keywords
  • SFE
  • mass spectrometry
  • egg yolk
  • chromatography
  • sulfonamides
  • beef liver
  • chicken liver
  • supercritical
  • extraction
  • atmospheric pressure chemical ionization
  • CLND
  • HPLC/MS
  • SFC
Date of Defense 1997-03-11
Availability unrestricted
Abstract
The objective of this research was to develop new sample preparation procedures for the isolation of sulfonamides, as well as, to determine the applicability of employing on-line nitrogen selective and mass spectrometric detection methods.

The first phase of this research investigated the effect of temperature and pressure on the supercritical fluid extraction (SFE) of sulfonamides from a spiked sand matrix. Temperature effects were either positive or negative with respect to extraction rate and total recovery, depending on the pressure and extraction fluid employed.

The second portion of this research compared trifluoromethane (CHF3) and carbon dioxide (CO2) as fluids for the extraction of sulfonamides from spiked non-fat dry milk, beef liver, and egg yolk were found to be more selective using CHF3 than CO2. The polar trifluoromethane improved the extraction efficiency of the polar sulfonamides from the biological matrices and also reduced the amount of co-extractives.

The next phase of this research considered the effect of organic modifier and CO2 in the SFE of sulfonamides from chicken liver, beef liver and egg yolk. Methanol, ethanol, acetone, acetonitrile were compared to determine optimum conditions. A SFE method employing 20% acetonitrile modified CO2 yielded quantitative recovery of sulfonamides from chicken liver, but 20% acetone modified CO2 was required to obtain quantitative recovery from beef liver. Either 20% acetone or 20% acetonitrile yielded quantitative recovery from egg yolk.

The last phase of this research focused on the evaluation of selective detection methods for sulfonamide analysis. Chemiluminescence nitrogen detection (CLND) parameters were optimized for use with packed column supercritical fluid chromatography (SFC) yielding a minimum detectable quantity (MDQ) of 5 ng of sulfamethazine, on column. Improvements in the detector design decreased the MDQ to 0.5 ng, while, decreasing the column diameter further reduced the MDQ to 125 pg. The second part of this phase evaluated PLC/Atmospheric pressure chemical ionization (APCI) mass spectrometry for the detection of sulfonamides. Sensitivity in selective ion mode was found to be as low as 50 pg on column for sulfamethazine. Supercritical fluid extracts of sulfonamides spiked at 100μg/kg in chicken liver were found to be readily detected by this method.

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