Date of Award

9-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Ali Shaikh

Abstract

Bile acids are water- soluble steroids and biological emulsions useful in the digestion process of food. The conjugated bile acids play a major role in fat metabolism. Deconjugation of conjugated bile acids by bacterial enzymes produces free bile acids in the colon. The conversion of these primary bile acids takes place in the gut by bacterial flora. It is postulated that a difference in the molecular forms of various bile acids and their concentration profiles exists among various animals, depending upon their food habits and type of bacterial flora. Consequently, it may be possible to distinguish various types of carnivorous wild animals by determining the bile acid profiles in their feces. Chromatography coupled with mass spectrometry is a versatile analytical technique for the separation and detection of isomeric bile acids. A rapid, sensitive and highly specific HPLC-ESI/MS method has been developed for the determination of bile acid profiles in the scat samples of wild animals. Eleven bile acid standards were used for the analysis. Mixture of standard unconjugated as well as glycine and taurine conjugated bile acids were separated and detection was performed using ESI-MS/MS. Bile acid samples were extracted from scat by solid phase extraction. Separation via HPLC was achieved using gradient reverse phase chromatography with methanol/water containing 0.4 M ammonium acetate (60/40, v/v) and 0.1% formic acid on a C18 column. Excellent separation, resolution and retention time was achieved by this method and is very easy for detection and quantification. The LC-MS method is more sensitive and selective compared to the GC-MS methods described earlier. PROJECT-II ABSTRACT A wide variety of new sulfonamide compounds are being synthesized to increase the potency and to overcome the resistant of bacteria towards these drugs. Coumarin sulfonamides are the compounds with coumarin group and heterocyclic rings on N4 and N1 positions of sulfonamide respectively. The chemical structure and biological activity studies have been conducted for these newly synthesized sulfonamide compounds. An analytical method is required for the identification and quantification of these new sulfonamide drugs. High performance liquid chromatography coupled with mass spectrometry is a very sensitive and selective method in the determination of molecular weight and fragmentation pattern of these new sulfonamides. A gradient method has been created to separate the mixture of eight coumarin derived sulfonamides. This method is validated by plotting calibration curves and showing the results of good linear correlation. All eight sulfonamides were ionized using negative polarity and detection was performed by ESI-MS/MS technique. This method is very reliable, rapid and specific for polar and non polar coumarin sulfonamides having close retention times. Tandem mass spectrometry with single ion monitoring is one of the suitable detection methods for the study of fragmentation pattern in the sulfonamide molecule. Fragmentation of sulfonamides using three different ionization voltages produced different ions based on the conditions. These studies can be helpful in the structural analysis and metabolic studies of the sulfonamides.

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