A three-dimensional metal hydroxide activated in an alkaline electrolyte used for electrochemical simultaneous detection of 5-hydroxytryptophan and tryptophan

An electrochemical sensor was designed for simultaneous detection of 5-Hydroxytryptophan (5-HTP) and tryptophan (L-Trp) based on a FeZnSn three-dimensional metal hydroxide activated in an alkaline electrolyte/ glassy carbon electrode (FeZnSn-TDHae/GCE). The results showed that the electrochemical activation method can effectively reduce the charge transfer resistance of FeZnSn three-dimensional metal hydroxide (FeZnSn-TDH) hardly affecting the electrochemical active surface areas, in which the charge transfer resistance of FeZnSn-TDHae was only one quarter of FeZnSn-TDH, and the DPV current response values of 5-HTP and L-Trp on FeZnSn-TDHae/GCE were 2.36 and 1.91 times that of on GCE. The modified working electrode had the wide linear response range of 1–800 μM and 3–800 μM for simultaneous detection of 5-HTP and L-Trp, and the detection limits of 5-HTP and L-Trp obtained in this work were 0.7398 μM and 1.2209 μM, respectively. Furthermore, the sensor was applied to the simultaneous detection of 5-HTP and L-Trp in human serum albumin samples by standard adding method.