Glutaraldehyde

Overview
Glutaraldehyde is a colorless liquid with a pungent odor used to sterilize medical and dental equipment. It is also used for industrial water treatment and as a chemical preservative. However, it is toxic, causing severe eye, nose, throat and lung irritation, along with headaches, drowsiness and dizziness.

Glutaraldehyde is an oily liquid at room temperature (density 1.06 g/mL), and miscible with water, alcohol, and benzene. It is used as a tissue fixative in electron microscopy. It is employed as an embalming fluid, is a component of leather tanning solutions, and occurs as an intermediate in the production of certain industrial chemicals. Glutaraldehyde is frequently used in biochemistry applications as an amine-reactive homobifunctional crosslinker. The oligomeric state of proteins can be examined through this application.

Monomeric glutaraldehyde can polymerize by aldol condensation reaction yielding alpha,beta-unsaturated poly-glutaraldehyde. This reaction usually occurs at alkaline pH values.

Uses
A glutaraldehyde solution of 0.1% to 1.0% concentration may be used for system disinfection and as a preservative for long term storage.

Glutaraldehyde is used in electron microscopy. It kills cells extremely quickly, and is used to fix specimens such as bacteria, plant material, and human blood cells. This is usually done before the dehydration process.

Glutaraldehyde is also used in SDS-PAGE to fix proteins and peptides prior to staining. Typically, a gel is treated with a 5% solution for approximately one half hour, after which it must be thoroughly washed to remove the yellow stain brought about by reacting with free tris.

A polymerized isomer of glutaraldehyde trademarked as polycycloglutaracetal by Seachem Laboratories, Inc. is the active ingredient in a product called Flourish Excel, a fertilizer for aquatic plants. It is claimed that it provides a bioavailable source of carbon for higher plants that is not available to algae. Though not marketed as such due to federal regulations, the biocidal effect of glutaraldehyde kills most algae at concentrations of 0.5 - 5.0 ppm. These levels are not harmful to most aquatic fauna and flora. Adverse reactions have been observed by some aquarists at these concentrations in some aquatic mosses, liverworts, and vascular plants.