Sodium Benzoxazole-2-Sulfonate: A Derivatisation Reagent for the Analysis of Amines and Amino Acids by HPLC with Fluorescence or UV Detection

Abstract

The preparation of sodium benzoxazole-2-sulfonate and its use as a reagent for the formation of fluorescent derivatives of amines and amino acids is described. Sodium benzoxazole-2-sulfonate is readily prepared by boiling 2-chlorobenzoxazole with sodium sulfite. Sodium benzoxazole-2-sulfonate is non-fluorescent, but reacts with amines and amino acids to give derivatives which exhibit intense blue fluorescence. The solubility of the compound in water also makes it particularly advantageous as a reagent for the derivatisation of amino acids. Furthermore, sodium benzoxazole-2-sulfonate may be tagged onto an ion-exchange resin, in which form it may be used for heterogeneous on-line pre- or post-column derivatisation of amines and amino acids.