Method to determine automatically the sequence of amino acids

Claim 1

In a method for automatically converting a thiazolinone amino acid into a phenylthiohydantoin amino acid in the process of amino acid sequence analysis of proteins or peptides by heating said thiazolinone amino acid for a short period of time in acidic solution and transferring such solution into an organic solvent to form a solution which is appropriate for identification or further purification, the improvement that comprises introducing, with the continuous exclusion of oxygen, by the means of an inert gas flow, a solution of a thiazolinone amino acid, immediately after its formation in a solvent appropriate for said conversion, into a reaction vessel where it is evaporated to dryness at a temperature between 50° and 80°C., adding, while maintaining said temperature, an aqueous trifluoro acetic or dilute hydrochloric acid solution containing an SH-group containing substance selected from the group conssiting of dithioerythrite, β-mercaptoethanol, ethane dithiol, butane dithiol or butane thiol, in an amount which, at said temperature and flow through of said inert gas, completely evaporates within 30 to 40 minutes, dissolving the residue from the evaporation stage by spraying over it a mixture of 6 to 8 parts of volume of 1,2-dichloroethane and 4 to 2 parts of volume of methanol, and removing the resultant solution from said reaction vessel.