PHOSPHORESCENCE STUDIES OF FOLATE

A room temperature phosphorescence analysis of folate was developed, r esulting in the construction of a linear calibration curve within the range of 60-1000 ng. Relative standard deviations were approximately 2 % for triplicate measurements. The phosphorescence properties of analy tically pure folic acid were evaluated at 77 and 298 K on a sodium ace tate-impregnated paper support and on other media. Evidence is present ed to support the existence of an intricate intramolecular energy tran sfer scheme within the folate molecule. Our results indicate that only the pterin ring system within folate appears to yield phosphorescence when studied on a sodium acetate-impregnated paper support or in aque ous alcoholic rigid glasses. The specific phosphorescent properties of a series of folate constituents are also described. Some of the resul ts presented within this paper are in contrast to earlier reports on t he phosphorescence properties of folate, and explanations for these di screpancies are provided.