Although caffeine is planet earths most widely consumed drug, and has its main source in the coffee bean, it can be routinely detected in blood and urine. Measurement of caffeine and other xanthines such as theobromine and theophylline can be useful to forensic toxicologists offering interpretation to coroners and medical examiners as to cause and manner of death in forensic investigations. Previous methods of analysis have employed liquid- liquid extractions under weak acid and basic conditions (separately) to isolate the compounds. At this presentation an alternative solution is offered.In this presentation attendees will learn about solid phase extraction performed in mixed mode operation and the chemistry involved in the isolation of caffeine and other xanthines including theobromine, theophylline from biological samples (blood/ urine). The use of pKa data to determine optimized extraction conditions will also be discussed. Attendees will also learn about how the solid phase extraction was performed in both hydrophobic mode and ion exchange modes using ethyl acetate/ methanol , and ethyl acetate/ acetonitrile/ ammonium hydroxide, respectively as elution solvents. After elution and evaporation separation of the xanthines in this procedure was carried out using liquid chromatography in isocratic mode employing a C18 column (150 x 2.1 mm ( 3μm)) and a mobile phase consisting of acetonitrile: formic acid (0.1 % aqueous) (10: 90)) at a flowrate of 0.1 mL/ minute. Detection of the compounds was carried out using photodiode array in scanning mode (200nm- 350nm).
You can can attend the presentation at the 34th annual NEAFS meeting October 1st - October 4th, 2008 at the Renaissance Westchester Hotel, White Plains, NY.
