In recent years, the introduction of surface-enhanced Raman spectroscopy (SERS) in the field of cultural heritage investigations has significantly improved the possibilities of successfully identifying organic colorants, a class of artists’ materials that has been widely used in textile dyeing, paintings and other polychrome works of art since antiquity. Over the years, a number of SERS methodologies have been developed by different research groups to be applied to the analysis of dyes, including many types of metal substrates as well as several procedures of sample pretreatment. In the present work, a comparative study has been carried out to shed light on the main advantages and disadvantages of the most relevant SERS approaches recently introduced in art analysis, namely SERS on Ag nanoparticles produced by laser photoreduction of AgNO3 solutions [Cañamares et al., 2007] and SERS on Ag colloids synthesized by microwave-supported glucose reduction of silver sulfate in the presence of sodium citrate as a capping agent [Leona, 2009]. Experiments on citrate/glucose microwave nanoparticles were conducted both in association with an extractionless HF gas-solid hydrolysis procedure [Leona et al., 2006] and without any pretreatment [Brosseau et al., 2009]. The performances of such methodologies for the ultrasensitive detection of a number of colorants from different supports were evaluated. Results obtained from pure dyes were compared with those achieved on actual samples, i.e. fragments from dyed paper and textiles, as well as lakes and glazes from several works of art. Extraction in HF vapours followed by the deposition of Ag citrate/glucose microwave nanoparticles on top of the sample was found in most cases to be the easiest and most rapid way to obtain high quality spectra. Indeed, such approach allowed us to record well resolved and extremely reproducible SERS spectra with high enhancement factors in less than 10 minutes for the great majority of samples here examined, leading to achieve, for colorants on different supports, a reliable fingerprint within very short times of analysis.
Comparative study of surface-enhanced Raman scattering (SERS)methodologies for the detection of organic colorants in cultural heritage investigations / F. Pozzi, M. Leona. ((Intervento presentato al 6. convegno International Congress on the Application of Raman Spectroscopy in Art and Archaeology tenutosi a Parma nel 2011.
Comparative study of surface-enhanced Raman scattering (SERS)methodologies for the detection of organic colorants in cultural heritage investigations
F. PozziPrimo
;
2011
Abstract
In recent years, the introduction of surface-enhanced Raman spectroscopy (SERS) in the field of cultural heritage investigations has significantly improved the possibilities of successfully identifying organic colorants, a class of artists’ materials that has been widely used in textile dyeing, paintings and other polychrome works of art since antiquity. Over the years, a number of SERS methodologies have been developed by different research groups to be applied to the analysis of dyes, including many types of metal substrates as well as several procedures of sample pretreatment. In the present work, a comparative study has been carried out to shed light on the main advantages and disadvantages of the most relevant SERS approaches recently introduced in art analysis, namely SERS on Ag nanoparticles produced by laser photoreduction of AgNO3 solutions [Cañamares et al., 2007] and SERS on Ag colloids synthesized by microwave-supported glucose reduction of silver sulfate in the presence of sodium citrate as a capping agent [Leona, 2009]. Experiments on citrate/glucose microwave nanoparticles were conducted both in association with an extractionless HF gas-solid hydrolysis procedure [Leona et al., 2006] and without any pretreatment [Brosseau et al., 2009]. The performances of such methodologies for the ultrasensitive detection of a number of colorants from different supports were evaluated. Results obtained from pure dyes were compared with those achieved on actual samples, i.e. fragments from dyed paper and textiles, as well as lakes and glazes from several works of art. Extraction in HF vapours followed by the deposition of Ag citrate/glucose microwave nanoparticles on top of the sample was found in most cases to be the easiest and most rapid way to obtain high quality spectra. Indeed, such approach allowed us to record well resolved and extremely reproducible SERS spectra with high enhancement factors in less than 10 minutes for the great majority of samples here examined, leading to achieve, for colorants on different supports, a reliable fingerprint within very short times of analysis.Pubblicazioni consigliate
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