LSD chromatography

The formation of a charge-transfer complex is accompanied by the appearance of a new color band. Histologists have long been interested in charge-transfer reactions for developing staining procedures based on the appearance of a visible color. For example, Romanowsky-Giemsa staining is due to azure B and eosin Y molecules, which act as electron acceptor and donor in the formation of a purple-colored charge-transfer complex.

Color tests for the detection of hallucinogenic drugs hafe beenn developed. This was shown in 1973, when twenty different hallucinogens were applied to chromatography plates and then sprayed with one of various chromogenic reagents. The formation of a color band was dependent on the electron-donating properties of the drug molecule.

“As would have been expected, the polycyclic and consequently more “electron-rich” hallucinogens, such as the harmine derivatives gave stronger colors than the simple monocyclic beta-phenylethylamines derivatives such as mescaline, TMA, DOM, or 2,3-dimethoxy-amphetamine,” (R.A. Heacock, 1973)

The tryptamine derivatives DMT, methyltryptamine, and alpha-methyltryptamine reacted strongly with tetracyanoethylene (TCNE), an electron acceptor used as the color test reagent. Beta-carboline derivatives 6-methoxyharmalan and harmaline gave intense colors with TCNE and all electron acceptors studied. Ibogaine and LSD were easily detected with TCNE. The chromatographic evidence suggests that the broadly defined class of hallucinogens function as electron donors, because one of the most characteristic evidence for a charge-transfer process is the appearance of a new absorption band.

Erspamer was the first scientist to study enteramine (serotonin) in depth. His technique involved staining with the Ehrlich reaction to test for the presence of serotonin. Also referred to as Van Urk's reagent, Ehrlich's reagent is 2% dimethylaminobenzaldehyde in hydrochloric acid. It forms a purple charge-transfer complex with serotonin as well as most indoles and chlorpromazine. A purple charge-transfer complex is formed when Ehrlich's reagent is mixed with LSD. Psilocybin gives a violet color characteristic of indoles in the Van Urk reaction (A. Hofmann, 1961).

From lsd spectroscopy

The LSD-Van Urk complex has an absorption band at 520 nm. Chlorpromazine-Van Urk complex also has an absorption peak at 520 nm. As predicted by its HOMO energy, chlorpromazine is an excellent electron donor, so it is not surprising that chlorpromazine would form a charge-transfer reactions with the Van Urk reagent which functions as an electron acceptor.

"The procedure allows for a simple, rapid, and accurate determination of small quantities of chlorpromazine." (B.S. Murty, 1970)

Chlorpromazine is considered to be an antipsychotic drug and LSD is considered to be one of the most powerful hallucinogen drugs known to man. There aren't too many similarities of the effects of these drugs, but they cause a distinguishable effect on the brain, and may be able to provide some information about consciousness alteration by their mechanism. There are many electronic similarities between LSD and chlorpromazine. LSD and chlorpromazine both have a low transport number, and they both react with Van Urk reagent to produce a macromolecular complex with an absorption peak at 520 nm. The similarites between LSD and chlorpromazine could be related to their common anthracene-like structure, known to have exceptional electron-donating and electron-receiving properties.


Reference

Heacock R. A. and J. E. Forrest. (1973). The use of electron-acceptor reagents for the detection of some hallucinogens. J.Chromatogr. 78, 240-250. 10.1016/S0021-9673(01)99063-6

HOFMANN A. (1961). Chemical pharmacological and medical aspects of psychotomimetics. J.Exp.Med.Sci. 5, 31-51.

Murty B. S. and R. M. Baxter. (1970). Spectrophotometric determination of chlorpromazine in pharmaceutical dosage forms. J.Pharm.Sci. 59, 1010-1011. 10.1002/jps.2600590721