Can r-graphene oxide replace the noble metals in SERS studies: The detection of acrylamide

Polyacrylamide acts as a very common water purifier worldwide. Unfortunately, it leaves hazardous and toxic residues of its monomer, acrylamide (C₃H₅NO), in water sources. The World Health Organization (WHO), the Food and Agriculture Organisation of the United Nations (FAO) and the European Union (EU) set the maximum contaminant level of acrylamide in drinking water to 0.1-0.5 μ gL^-1. This environmental risk encouraged our efforts to develop surface-enhanced Raman spectroscopy (SERS) probes that are easy and simple to fabricate, and also have superb detection ability. We report down to 0.071μg^L-1 acrylamide detection with good reproducibility, which is even lower than the WHO, FAO and EU requirements, and may be used as a powerful analytical alternative for detection. In this manuscript, we present a practical route to fabricate these detection substrates for detection of ultra-low concentrations of aqueous acrylamide solutions. The facile method is based on deposition of graphene oxide on Si wafers by ultrasonication, followed by surface reduction. These substrates require no adhesion layer or pretreatment with O₂ plasma or aminopropyl triethoxysilane for the coating process. Sonochemical deposition of silver nanoparticles on the substrates is also carried out and the product compared with the proposed Si-reduced graphene oxide wafers.