Fabrication of plasmonic cotton gauze-Ag composite as versatile SERS substrate for detection of pesticides residue

Abstract

Plasmonic cotton gauze-Ag composite were fabricated through a simple, instant and cost-effective way, in which the Ag NPs were immobilized on the surface of cotton gauze through in-situ growth process. The in-situ growth of Ag NPs was started from electroless-immobilized Ag seeds on the surface of cotton fiber, which could form numerous hot spots for SERS compared with current method. The cotton gauze-Ag composite was employed as versatile substrate in surface-enhanced Raman scattering (SERS) spectroscopy. The plasmonic cotton gauze-Ag exhibited excellent uniformity, temporal stability and enhanced effect for SERS measurement. The detection limit of P-aminothiopheno (PATP) was 10-8 M. Furthermore, the plasmonic cotton gauze-Ag composite presented excellent flexibility and adsorption capability, which enable to adsorb and detect pesticide residue from irregular surface of cucumber directly by simple swabbing process, the detection limit could achieve 0.1 ppm. The cotton gauze-Ag composite also shown excellent selectivity is SERS sensing. The fabrication method could be simply extended to other cellulose compound, such as absorbent cotton, paper and even for natural fibers. This study proposed a new method for fabricating the cost-effective, eco-friendly and flexible SERS substrates.