Trace molecule detection methods are normally based on chromatography coupled to mass spectrometry. However, despite the high sensibility of this technique, it is time-consuming, expensive, and not portable. To overcome these limitations, alternative techniques based on Surface Enhanced Raman Spectroscopy (SERS) and flexible and cheap substrates like filter paper, are being used to develop innovative analytical methods that could be used in a wide variety of fields. In the present study, a simple, cheap, portable, and practical SERS substrate for rapid trace analyte detection is proposed. Gold nanospheres (AuNP) embedded in a coffee filter paper are used to enhance Raman signals of the adsorbed analyte and to discriminate the concentration of two different kinds of dyes with minimum volume, Rhodamine B (RhB) - a Raman reporter – and carmine – a molecule of great interest in the study of cultural heritage materials and in food industry. By using this SERS system, it is possible to detect an effective dynamic range of over three orders of magnitude of RhB down to a limit of detection (LOD) as low as 2x10-6 M for Rhodamine B (RhB) and carmine (LOD = 5x10-4 mg/mL). The latter molecule is broadly used in the food industry and of great interest in cultural heritage materials, where not always is possible to have a vast amount of sample. Therefore, the sensitive and portable detection of carmine by this SERS system could potentially be of great help in these two fields.

Development of an accessible filter paper-based SERS system for dye trace analysis

ACS Spring Meeting 2021

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