Near-Infrared Surface-Enhanced Raman Spectroscopy (NIR-SERS) for the Identification of Eosin Y: Theoretical Calculations and Evaluation of Two Different Nanoplasmonic Substrates

Abstract

This work demonstrates the development of near-infrared surface-enhanced Raman spectroscopy (NIR-SERS) for the identification of eosin Y, an important historical dye. NIR-SERS benefits from the absence of some common sources of SERS signal loss including photobleaching and plasmonic heating, as well as an advantageous reduction in fluorescence, which is beneficial for art applications. This work also represents the first rigorous comparison of the enhancement factors and the relative merits of two plasmonic substrates utilized in art applications; namely, citrate-reduced silver colloids and metal film over nanosphere (FON) substrates. Experimental spectra are correlated in detail with theoretical absorption and Raman spectra calculated using time-dependent density functional theory (TDDFT) in order to elucidate molecular structural information and avoid relying on pigment spectral libraries for dye identification.

Ionization and tautomerism of methyl fluorescein and related dyes

“…Nowadays, much attention has been given to the structure, absorption, and fluorescence of fluorescein dyes in solution [1][2][3][4][5][6][7][8][9]. The recent studies of the structure and spectra in the gas phase are of special interest [10][11][12][13][14].…”

Balancing the Initiation and Molecular Recognition Capabilities of Eosin Macroinitiators of Polymerization‐Based Signal Amplification Reactions

“…Because the eosin moiety is known to exist in its dianionic form above pH 7 [21] and the acrylic acid residues of poly(acrylic acid-co-acrylamide) are also ionizable, macroinitiator 8 was treated under alkaline conditions in order to increase solubility. Resulting signal and background intensities at pH 11 were both 2-5 times lower than at pH 7.4 (Figure 3a and b).…”

Raman Spectroscopy of cultural heritage Materials: Overview of Applications and New Frontiers in Instrumentation, Sampling Modalities, and Data Processing

“…Fabricated by drop-casting and self-assembly of microspheres (usually silica or polystyrene) on a glass slide, subsequently covered by a thin layer (approximately 200 nm) of vapor deposited Ag or Au, these substrates generally give high-quality spectra with higher enhancement factors than colloids [150], and can be tuned by appropriately choosing the size of the microspheres used so as to give rise to LSPRs at different wavelengths [278,303,304]. The major drawback of these systems is that the analyte needs to be brought into solution, and often they suffer from contamination of carbonaceous and other spurious materials that get preferentially adsorbed on the metallic coating of the microspheres.…”