Development of electrochemical sensor based on polyalanine/CuCl-Gr/DWCNTs for highly sensitive detection of glyphosate

Abstract

In this study, a hybrid film based on copper chloride doped graphene/double-walled carbon nanotubes (CuCl-Gr/DWCNTs) was prepared for further application in detection of glyphosate (Gly) at low levels. Gr/DWCNTs film was first fabricated on copper foil and then modified with CuCl using thermal chemical vapor deposition (CVD) technique, before being transferred onto gold screen printed electrode (AuE). An ad-layer polyalanine (PolyA) was introduced on the top of CuCl-Gr/DWCNTs hybrid film by direct electro-deposition from alanine monomer in order to facilitate immobilization of enzyme molecules. The as-prepared PolyA/CuCl-Gr/DWCNT film was finally used for developing Gly electrochemical sensor based on inhibition of Gly towards urease enzyme. The developed Gly sensor showed a high sensitivity of 1383 (μA.ppb−1.cm−2) and a low detection limit (LOD) of 0.54 × 10−3 ppb in a wide concentration range of 10−3 ppb - 50 ppb. Moreover, the sensor was also applied to the detection of Gly in river water samples, with recoveries ranging from 112.8 % to 113.9 % (RSD: 1.54–2.03 %). The results suggested that the developed sensor with high sensitivity can be used for the detection of Gly in water sources.