"Urine fortified with LSD and stored in amber glass or nontransparent polyethylene containers showed no change in concentration under any light conditions. Stability of LSD in transparent containers under light was dependent on the distance between the light source and the samples, the wavelength of light, exposure time, and the intensity of light. After prolonged exposure to heat in alkaline pH conditions, 10 to 15% of the parent LSD epimerized to iso-LSD. Under acidic conditions, less than 5% of the LSD was converted to iso-LSD. We also demonstrated that trace amounts of metal ions in buffer or urine could catalyze the decomposition of LSD and that this process can be avoided by the addition of EDTA. This study demonstrates the importance of proper storage conditions of LSD in urine in order to insure proper analytical testing results over time."
As to the transdermal activity IIRC Hofmann himself said that it isn't really active and his own trip was probably caused by him getting some on his hands and then rubbing it into a mucous membrane (eyes, nose, mouth).
https://www.erowid.org/references/refs_view.php?ID=8647
As to the transdermal activity IIRC Hofmann himself said that it isn't really active and his own trip was probably caused by him getting some on his hands and then rubbing it into a mucous membrane (eyes, nose, mouth).