Figure 1.

High-performance liquid chromatography (HPLC) spectrum of (A) 1-DNJ standard, (B) blank, and (C) FM preparation. 1-DNJ in the FM preparation was extracted with 0.05 mol/l HCl, made to react with fluorenylmethoxycarbonyl (FMOC)-Cl to generate the DNJ–FMOC derivative, and separated on the SUPELCO Ascentis 5-μm C18-A column at 25°C. The mobile phase consisted of acetonitrile:0.1% aqueous acetic acid (55:45) with a flow rate of 1.0 ml/min. The fluorescence detector was operated at λex = 254 nm and λem = 322 nm