resumo
An important feature in the fabrication of surface-enhanced Raman scattering (SERS) platforms is, together with the high efficiency, to allow the rapid collection and analysis of a vestigial analyte. Conventional substrates based on rigid solid materials or metal hydrosols are not suitable for sample extraction, limiting their application in areas such as water quality monitoring. Herein, we have developed a strategy to fabricate SERS active substrates (Ag/LCP) based on liquid-crystal polymer (LCP) textile fibers decorated with Ag nanoparticles (NPs). Two distinct methods for substrate preparation envisaging the SERS detection of the pesticide thiram have been explored in this research. In a first stage, we have investigated the usefulness of both approaches using ethanolic solutions of the pesticide thiram, and after real samples spiked with thiram were used to explore the analysis in real environment. The SERS analysis of thiram dissolved in Aveiro Estuary water and in fruit juices have provided enhancement factors of 1.67 x 10(7) and 3.86 x 10(5), respectively, using the Ag/LCP composites. Noteworthy, in the latter case, the detection limit (0.024 ppm) achieved is lower than the maximal residue limit (MRL) of 5 ppm in fruit, as prescribed by European regulations (EU) 2016/1. Moreover, the selectivity of the SERS substrates for different pesticides was also evaluated, analyzing distinct pesticides such as paraquat and sodium diethyldithiocarbamate. SERS active Ag/LCP/PA filter membranes were also prepared using Ag/LCP composites supported by a polyamide (PA) filter, which can be an easy alternative to prepare simple, highly efficient and low-cost SERS active filter membranes for water analysis.
palavras-chave
SURFACE-ENHANCED RAMAN; DITHIOCARBAMATE PESTICIDES; GOLD NANOPARTICLES; SPECTROPHOTOMETRIC DETERMINATION; SILVER NANOPARTICLES; METAL NANOPARTICLES; CHEMICAL-DETECTION; AG NANOPARTICLES; RAPID DETECTION; SPECTROSCOPY
categoria
Chemistry
autores
Fateixa, S; Raposo, M; Nogueira, HIS; Trindade, T
nossos autores
Helena Isabel Seguro Nogueira
Professor Auxiliar com Agregação
Sara Fateixa
Investigador Júnior
Tito Trindade
Professor Catedráticoagradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by Fundo Europeu de Desenvolvimento Regional (FEDER) under the PT2020 Partnership Agreement. S. Fateixa thanks Fundacao para a Ciencia e Tecnologia (FCT) for the Grant SFRH/BPD/ 93547/2013.