Determination of nicotine in e-liquids by electrochemical generation of surface-enhanced Raman scattering substrates

• TR-EC-SERS determination of nicotine in e-liquids. • Sensitivity and reproducibility are improved by pretreatment of the electrode. • Study of different electrolytic media for electrosynthesis of SERS substrates. • Trilinear data allow the detection of interfering compounds using PARAFAC analysis. Quantitative methods using surface-enhanced Raman scattering (SERS) for analysis in complex matrices are very attractive due to the high sensitivity and selectivity of this technique. In this work, a novel time-resolved electrochemical surface-enhanced Raman scattering (TR-EC-SERS) analytical method has been developed for the determination of nicotine in e-liquids of electronic cigarettes. One of the main challenges of SERS is its inherent lack of reproducibility. Here, this limitation was mitigated by employing an electrochemical pre-treatment step to generate a homogeneous distribution of silver nanoparticles (Ag-NPs) on a silver screen-printed electrode. The enhanced Raman scattering induced by the Ag-NPs enabled the detection of nicotine at nanomolar levels. The high sensitivity of the method allowed the quantitative analysis of diluted e-liquid samples, mitigating potential interferences from other components present in these complex matrices. Moreover, TR-EC-SERS, coupled with parallel factor analysis (PARAFAC), demonstrated the capability of trilinear spectroelectrochemistry data not only to detect nicotine but also to identify potential interfering compounds without prior knowledge of their spectral signatures. This multivariate approach offers significant potential for the detection of outliers in complex samples.