Absorptivity and Solid State and Solution Fluorescence of Mixed Aflatoxin Standards Stored in Solution and as Dry Films

Abstract Mixed anatoxin B1, B2, G1, and G2 standards were stored 1 year in chloroform and benzene solutions and as dry films at 28 and – 18°C. Weighted average molar absorptivity and solution and TLC plate fluorescence were used as indices of deterioration. Changes in all three indices were greater for standards stored at 28°C than for those stored at –18°C. Storage at 28°C resulted in appreciable deterioration of dry film standards. Both solution and plate fluorescence were more sensitive indices than molar absorptivity for detecting changes in the properties of stored standards. A good correlation was obtained between anatoxin concentration as measured by UV molar absorptivity and the plate fluorescence of the stored standards. An accelerated storage study of anatoxins B1 and G1 stored 34 days in benzeneacetonitrile (98 + 2) at 51°C showed no detectable change in molar absorptivity or plate fluorescence.