Figures of merit of a SERS method for Sudan I determination at traces levels

• SERS is proposed as a tool for detecting Sudan I quickly and economically.
• Enhancement of the Raman signal was determined.
• Figures of merit were evaluated (linear range, sensitivity, detection limit, etc.).
• Selectivity of Sudan I in front of other similar compounds was assessed.

A substrate for Surface-Enhanced Raman Scattering spectroscopy (SERS), electropolished Al, is proposed as a tool for a rapid and low cost determination of Sudan I. This dye has been used as an additive in some foodstuffs but it is now banned because of the health risk associated with its carcinogenic and mutagenic properties. Despite the presence of fluorescence, Raman spectra of Sudan I can be obtained using excitation lasers at 633 and 785 nm. To get rid of the spectral noise and fluorescence background, Savitzky–Golay smoothing and polynomial corrections were applied, respectively. The Raman signal was proved to be enhanced. A linear dependence was found between the logarithmic intensity at 1598 cm−1 peak versus the logarithmic concentration. The figures of merit were studied obtaining high sensitivity and low detection limits (10−7 M). A multivariate exploratory analysis (PCA) was used to study the ability of SERS to distinguish Sudan I from other similar compounds. Therefore, results show that SERS is a potential tool to determine Sudan I quickly and effectively.

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