Author (Your Name)

Mark Pecevich, Colby College

Date of Award


Document Type

Senior Scholars Paper (Colby Access Only)


Colby College. Chemistry Dept.


George Maier


In highly alkaline solution, thiamine exists as the yellow form which is converted to a colorless thick form, the nature and rate of this decay being solvent dependent. Since only the yellow form absorbs in the UV above 325nm, the decay has been followed spectrophotometrically at 345nm. A spectrophotometric thiamine assay has been proposed, based on the yellow form's decay in methanol. The method is dependent upon establishing that the first-order decay kinetics in water exist in methanol. It was found that the decay is proceeding via two paths, resulting in mixed decay kinetics. Attempts to block the second decay path were unsuccessful and has prevented development of the proposed assay. Another spectrophotometric assay method with limited application has also been described.


spectophotometric assay, thiamine


Full-text download restricted to Colby College campus only.