Surface-enhanced Raman scattering substrate for fuel oil analysis

A surface-enhanced Raman scattering (SERS) substrate for fuel oil analysis, comprising:

• a transparent substrate;
• and
• a nanocomposite composition comprising:
• a silver-loaded silica (Ag—SiO2) nanocomposite having a silica core and a silver/silica shell disposed around the silica core;
• and
• a zeolitic material having a nano porous structure;
• wherein the silver/silica shell contains silver nanoparticles uniformly distributed therein;
• wherein the Ag—SiO2 nanocomposite is uniformly disposed on a surface of the zeolitic material;
• wherein the nanoparticles of the Ag—SiO2 nanocomposite are spherical and have a mean particle size of 250 to 350 nanometers (nm);
• wherein the silver/silica shell of the Ag—SiO2 nanocomposite has a mean thickness of 50 to 350 nm and the silver nanoparticles in the silver/silica shell of the Ag—SiO2 nanocomposite have a mean particle size of 10 to 50 nm;
• and
• wherein the SERS substrate has a specific surface area in a range of 150 to 300 m2/g, a cumulative specific pore volume in a range of 0.2 to 0.3 cm3/g, and an average pore diameter of 4 to 7 nm.