Electrochemical detection of isocarbophos in apple and cabbage with Ti3C2TX/arginine and serine-functionalized graphene quantum dot@gold nanostar aerogel and target cycle dual signal amplification

Abstract

The paper reports one strategy for synthesis of Ti3C2TX/arginine and serine-functionalized graphene quantum dot@Au nanostar aerogel (Ti3C2TX/RS-GQD@Au). Positively charged RS-GQDs bound with negatively charged Ti3C2TX sheets to form Ti3C2TX aerogel. Then, HAuCl4 was in situ reduced with ascorbic acid in the presence of L-glutathione to form gold nanostars on Ti3C2TX sheets. The resulting Ti3C2TX/RS-GQD@Au shows one three-dimensional structure. The gold nanostars were homogeneously dispersed on Ti3C2TX sheets. Introduction of RS-GQD realizes construction of Schottky heterojunction. The presence of L-glutathione triggers an asymmetric structural evolution of gold nanocrystals and leads to more exposed high-index crystal facets. Unique structure achieves to high conductivity, structural stability and catalytic activity. Ti3C2TX/RS-GQD@Au was used for construction of electrochemical sensor for detection of isocarbophos coupled with target cycle amplification. The peak current at 0.27 V linearly increases with the increase of isocarbophos concentration between 1 × 10−11 and 8 × 10−16 M with 2.9 × 10−16 M of detection limit (S/N = 3). The analytical method provide advantage of sensitivity and specificity for detection of isocarbophos in apple and cabbage.