Novel Strategies for Rapid Analytical Preparation of Solid Samples
Creators: name: Alkhateeb, Fadi
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Chemistry--Analytical
subject: enhanced fluidity
subject: liquid, extraction
subject: fluoxetine hydrochloride
subject: solid sample preparation
subject: dried blood spot
subject: pressurized liquid
subject: rapid
subject: ultra-short column
subject: Gas Chromatography
subject: Flame Ionization Detection
subject: on-column injection
subject: polycyclic aromatic hydrocarbons
subject: organic pollutants
subject: Micro

description: This thesis describes successful advances in solid-liquid extraction methodology on several fronts from novel applications of existing extraction techniques, to the development of novel extraction methods. These advances aim to reduce the time and the consumption of costly, toxic, and environmentally hazardous solvents often employed in conventional extraction techniques. One such development involves using enhanced fluidity liquid extraction for the first time to extract Fluoxetine Hydrochloride and other polar drugs from various pharmaceutical formulations. Using this approach it is found that it can greatly reduce the organic solvent and the time requirements for pharmaceutical sample preparations. For example, employing an extraction fluid of 50% carbon dioxide / 50% methanol, produced an extraction recovery of Fluoxetine Hydrochloride from Prozac® capsules of 99 ± 2% in just 3 minutes using only about 5 mL of total methanol. Further, the method allows for the incorporation of modest amounts of water as a ternary modifier, which in turn significantly enhances the extractability of hydrophilic analytes. For example, the extraction recovery of Ascorbic Acid from tablets was improved from 10 ± 3% to 63 ± 2% after 10 minutes extraction when 10% water / 90% methanol was employed as a cosolvent instead of pure methanol. Another advancement in the area of solid-liquid sample preparations that involves developing a novel micro pressurized liquid extraction (µPLE) technique is also demonstrated in this thesis. The method employs rapid heating in a static mode to remove analytes from 5-10 mg samples in only a matter of seconds using only 125 µL of solvent. The required instrumentation and procedure are relatively simple and readily accessible to most laboratories. The method was explored with different samples and the results compared well to conventional PLE extractions of the same. As applications, the method was used for dried blood spot and polycyclic aromatic hydrocarbons samples. The method proved to be very rapid and solvent efficient compared to conventional extraction methods of such samples. Finally, the benefits of combining µPLE with an ultra-short GC-FID column apparatus in order to very rapidly monitor thermal degradation of a model pharmaceutical formulation are also demonstrated in this thesis. Using an ultra-short GC column ASA and its degradants were successfully analyzed and results compared well with HPLC for monitoring degradation of the analyte as a function of temperature. Coupling this with µPLE, it was found that a thermally degraded ASA tablet could rapidly be extracted and analyzed for its contents.