E q u i p m e n t and chemicals HPLC (High Pressure Liquid Chromatography): C18 column Settings: 280nm, 2.5mL/min (4000psi), isocratic conditions (10 MeOH : 90 aq) Balances Glassware: beakers, volumetric flasks, graduated cylinders, etc. Chemicals: Methanol (MeOH), deionized and milli-pore H 2 O, Thiamine (Vitamin B1), Riboflavin (Vitamin B2), Acetic Acid, NaOSA, Mobile Phase

P r o c e d u r e Determine best wave length to run lamp Create mobile phase(s) and sample solution(s) Run pump and inject sample Allow solution to flow through system completely Analyze results

P r o b l e m s E n c o u n t e r e d Inconsistent labeling of mobile phase Column problems (polarity, “clogs”) Air bubbles in tubing B1 disappearing in later tests Over pressurization of pump Estimations and assumptions in sample preparation

Results B1 was more polar compared to B2 Mobile phase content changed run time Air bubbles cause difficulties Composition of the column changes over time B2, in real samples, was detected