The separated carbamates are first saponified by sodium hydronde (Naoh) at 100°C to release an alcohol, carbonate, and methylamine. In the second post column reaction, methylamine reacts with o-phthalaldehyde (OPA) and the nucleophilic Thiorluor to form a highly fluorescent 1-methyl-2 dimethyl-2-dimethyl-ethylamine thioisoindole derivative (Figure 1-3).