3D plasmonic hotspot engineering toward ultrasensitive and rapid EC-SERS recognition of plasticizers

Public attention to the health and environmental risks from plasticizer exposure in daily life has led to legal restrictions on the use of plasticizers in products. However, the lack of rapid, sensitive, and reliable analytic methods hinders the effective screening of toxic materials. In the present work, we propose a novel electro-chemical surface-enhanced Raman spectroscopy (EC-SERS) technique for the detection of plasticizers such as phthalate esters (PAEs) and bisphenol A. The interior hotspots were realized through the EC deposition onto metal nanopillar (ECOMP) platforms in the presence of analytes within 2.5 min. The tiny molecules surrounded by Au produced sufficient amplification of SERS signals, leading to sub-parts -per-billion (sub-ppb) sensitivity for all the intended specimens. According to the three standard deviation equation, the limit of detection was determined to be 0.002 ppb. The ECOMP platforms with reproducibility (relative standard deviation of <10 %) and linear proportion (R-2 >= 0.93) were highly suitable for reliable quantitative investigation. A principal component analysis method recognized their slight differences in spectral features. The variability from the first two components was achieved to be 73 %, which separated individual plasticizer groups distinctly. The plasticizer extracted from an actual polyvinyl chloride sample was successfully detected using the proposed technique. The interaction of PAEs with ethanol and the delocalization of PAEs in ECOMP platforms were also discussed. The results demonstrate the feasibility of plasticizer-ECOMP platforms being widely used for onsite testing in industrial fields such as chemical and drug safety.