High Surface-Enhanced Raman Scattering (SERS) Amplification Factor Obtained with Silver Printed Circuit Boards and the Influence of Phenolic Resins for the Characterization of the Pesticide Thiram

Abstract

In this work, low-cost substrates with rough silver surfaces were prepared from commercial copper foil-covered phenolic board (CPB) and an aqueous solution of AgNO3, and were used for surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) measurements. A maximum SERS amplification factor of 1.2 × 10(7) was obtained for Rhodamine 6G (R6G), and use of the CPB resulted in a detection limit for Thiram pesticide of 0.5 µmol L(-1) The minimum detection level was limited by residual traces of phenolic groups that originated from the substrate resin, which became solubilized in the aqueous Ag(+) solution. It was found that the bands corresponding to the impurities had less influence in the Thiram analysis, which could be explained by the high affinity of sulfur for Ag surfaces. The influence of impurities in the SERS analyses therefore depended on the linkage between the rough silver surface and the analyte. The findings demonstrated the ease and effectiveness of using CPB to prepare a nanostructured surface for SERS.

Inkjet Printing of Ag and Polystyrene Nanoparticle Emulsions for the One-Step Fabrication of Hydrophobic Paper-Based Surface-Enhanced Raman Scattering Substrates

“…In the conventional Raman spectrum of thiram, the following vibrational bands are identified: 359 cm –1 , ν­(CH 3 –NC); 392 cm –1 , ν­(S–S); 438 cm –1 , δ­(CSS) and δ­(CNC); 558 cm –1 , ν sym (CSS) coupled to ν­(S–S); 850 cm –1 , methyl groups vibrations; 973 and 1035 cm –1 , ν­(C–S) and ν­(CS); 1138 cm –1 , ρ­(CH 3 ) and ν­(C–N); 1372 cm –1 , ν­(C–N) coupled to δ sym (CH 3 ); and 1452 cm –1 , δ asym (CH 3 ). ,, In the SERS spectrum of thiram on the Ag16×_PS 0.6 substrate, the band corresponding to the mode ν­(C–N) coupled to δ sym (CH 3 ) shifts from 1372 to 1379 cm –1 and is much more intense than in the conventional Raman spectrum. Some authors have suggested that the enhancement of this Raman band is due to the proximity of the CH 3 and CN groups to the surface of metal particles . Two new bands at 339 and 1503 cm –1 are observed in the SERS spectrum of thiram.…”

“…Two new bands at 339 and 1503 cm –1 are observed in the SERS spectrum of thiram. The band at 339 cm –1 is assigned to the Ag–S stretching mode and indicates interaction between thiram molecules and the silver surface . This interaction involves the cleavage of the disulfide bond present in the thiram molecule .…”

Uncommon and Emissive {[Au2(C3H6NS2)2][Au(C3H6NS2)2]2(PF6)2} Mixed Au+ and Au3+ Pseudotetranuclear Crystalline Compound: Synthesis, Structural Characterization, and Optical Properties

“…Figure shows the possible configurations of this linkage. Other examples of disulfide cleavage during adsorption on a metal surface have been previously reported for other organic sulfur-containing compounds . The presence of an intense SERS signal was due to the angle that S–Au–S–Ag makes with the surface, with bonds perpendicular to the surface being amplified due to the surface plasmon resonance.…”

“…Other examples of disulfide cleavage during adsorption on a metal surface have been previously reported for other organic sulfur-containing compounds. 24 The presence of an intense SERS signal was due to the angle that S−Au−S−Ag makes with the surface, with bonds perpendicular to the surface being amplified due to the surface plasmon resonance. The peaks associated with the N−C−S bond at 1474 and 1500 cm −1 (region (f) in Figure 4) were much smaller in the spectrum for the crystal compared to those in the spectrum for the ligand.…”

“…The Raman and surface-enhanced Raman scattering (SERS) experiments were performed using the same configuration setup and SERS substrates described elsewhere. 24 In the Raman experiments, the samples were excited at 810 nm with a 22 mW Ti−sapphire laser (NBR 110, Coherent) pumped at 532 nm (Coherent Verdi G, 7 W power). This excitation wavelength was chosen in order to avoid luminescence interference.…”