Multiple SERS detection of phenol derivatives in tap water

Phenols are by-products resulting from the petrochemical industry, they can occasionally appear as pollutants in rivers and seas and enter the food chain [1]. A typical characteristic of these pollutants is that they bioaccumulate in media and in bodies. The main harmful effect of the accumulation of these are mutagenic and carcinogenic effects, although a large amount of them can cause acute effects [2]. Phenols are colourless compounds, which could be detected by UV-VIS spectrometry using a reagent that reacts with them, giving rise to a coloured compound, as has been done in other experiments with pollutants [3]. The problem with this spectroscopic method is that it does not allow multiple detection of phenols because the presence of several phenols in the same sample prevents the determination. Therefore, a method based on SERS (surface-enhanced-Raman spectroscopy) has been proposed. In this way, the compound resulting from the reaction between Gibbs reagent (dbqc) and the phenol derivative used could be quantified, using SERS spectroscopy. For this, substrates of 60 nm gold nanospheres were used that allowed to amplify the signal. The experiment was tested for the case of phenol, o-cresol and 1-naphthol, and their binary and ternary mixtures. It has been possible to quantify individual samples up to 5 µm of each phenol derivative using principal component analysis (PCA), using this same technique it has been possible to quantify binary samples up to this same quantity and perform a semi-quantitative method that allows the detection of the presence of a mixture of these three phenols.