Picric Acid - Uses

Uses

By far, the largest use has been in munitions and explosives.

It has found some use in organic chemistry for the preparation of crystalline salts of organic bases (picrates) for the purpose of identification and characterization.

In metallurgy, a picric acid etch has been commonly used in optical metallography to reveal prior austenite grain boundaries in ferritic steels. The hazards associated with picric acid has meant it has largely been replaced with other chemical etchants. However, it is still used to etch magnesium alloys, such as AZ31.

Bouin solution is a common picric acid-containing fixative solution used for histology specimens. It improves the staining of acid dyes, but it can also lead to hydrolysis of any DNA in the sample.

Clinical chemistry lab testing utilizes picric acid for the Jaffe reaction to test for creatinine. It forms a colored complex that can be measured using spectroscopy.

Much less commonly, wet picric acid has been used as a skin dye or temporary branding agent. It reacts with proteins in the skin to give a dark brown color that may last as long as a month.

In the early 20th century, picric acid was stocked in pharmacies as an antiseptic and as a treatment for burns, malaria, herpes, and smallpox. It was most notably used for the treatment of burns suffered by victims of the Hindenburg disaster in 1937.

Picric acid emits a high-pitched whine during combustion in air and this has led to its widespread use in fireworks.

Picric acid has been used for many years by fly tyers to dye mole skins and feathers dark olive green. Its popularity has been tempered by its toxic nature.