Editing LSD (section)

===Stability===
"LSD," writes the chemist [[Alexander Shulgin]], "is an unusually fragile molecule ... As a salt, in water, cold, and free from air and light exposure, it is stable indefinitely."<ref name="tihkal" />

LSD has two [[labile]] protons at the tertiary stereogenic C5 and C8 positions, rendering these centers prone to [[epimerisation]]. The C8 proton is more labile due to the electron-withdrawing [[carboxamide]] attachment, but the removal of the [[chiral]] proton at the C5 position (which was once also an alpha proton of the parent molecule [[tryptophan]]) is assisted by the inductively withdrawing nitrogen and pi electron delocalisation with the [[indole]] ring.{{Citation needed|date=May 2011}}

LSD also has [[enamine]]-type reactivity because of the electron-donating effects of the indole ring. Because of this, [[chlorine]] destroys LSD molecules on contact; even though chlorinated tap water contains only a slight amount of chlorine, the small quantity of compound typical to an LSD solution will likely be eliminated when dissolved in tap water.<ref name="tihkal" /> The [[covalent bond|double bond]] between the 8-position and the [[aromatic hydrocarbon|aromatic ring]], being conjugated with the indole ring, is susceptible to [[nucleophilic]] attacks by water or [[alcohol (chemistry)|alcohol]], especially in the presence of UV or other kinds of light. LSD often converts to "lumi-LSD," which is inactive in human beings.<ref name="tihkal" />

A controlled study was undertaken to determine the stability of LSD in pooled urine samples.<ref>{{cite journal | vauthors = Li Z, McNally AJ, Wang H, Salamone SJ | title = Stability study of LSD under various storage conditions | journal = Journal of Analytical Toxicology | volume = 22 | issue = 6 | pages = 520–5 | date = October 1998 | pmid = 9788528 | doi = 10.1093/jat/22.6.520 | doi-access = free }}</ref>

The concentrations of LSD in urine samples were followed over time at various temperatures, in different types of storage containers, at various exposures to different wavelengths of light, and at varying pH values. These studies demonstrated no significant loss in LSD concentration at 25&nbsp;°C for up to four weeks. After four weeks of incubation, a 30% loss in LSD concentration at 37&nbsp;°C and up to a 40% at 45&nbsp;°C were observed. Urine fortified with LSD and stored in amber glass or nontransparent polyethylene containers showed no change in concentration under any light conditions. The 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. It was also demonstrated that trace amounts of metal ions in the buffer or urine could catalyze the decomposition of LSD and that this process can be avoided by the addition of [[EDTA]].