Azomethine H

8-Hydroxy-1-(salicylideneamino)-3,6-naphthalenedisulfonic acid, disodium salt.

Azomethine H is a colorimetric reagent for boron detection; it forms an orange complex with boron in aqueous solution. To detect boron in plant samples, EDTA is used to mask copper, iron, and aluminum ions. Azomethine H is used to detect microgram levels of boron in glass and steel samples.