abstract
In this work, we report the synthesis of magneto-plasmonic dendrimer-based nanosorbents containing Au nanostars and we demonstrate that they can be used as versatile optical sensors for the detection of pesticides in spiked water samples. The magnetic hybrid nanoparticles were obtained by conjugating silica-functionalized G5-NH2 PAMAM dendrimers to silica-coated magnetite cores. The resulting magnetic-PAMAM conjugates were then used to reduce and sequester Au seeds for the subsequent in situ growth of Au nanostars. The dendrimer-based magneto-plasmonic substrates containing the Au anisotropic nanophases were then investigated regarding their ability to monitor water quality through surface-enhanced Raman scattering (SERS) spectroscopy. As a proof-of -concept, the ensuing multifunctional materials were investigated as SERS probing systems to detect dithiocar-bamate pesticides (ziram and thiram) dissolved in water samples. It was observed that the magneto-plasmonic hybrid materials enhance the Raman signal of these pesticides under variable operational conditions, suggest-ing the versatility of these systems for water quality monitoring. Moreover, a detailed analysis of the SERS data was accomplished to predict the adsorption profile of the dithiocarbamate pesticides to the Au surface.
keywords
PAMAM DENDRIMERS; GOLD NANOSTARS; METAL NANOPARTICLES; FE3O4 NANOPARTICLES; GRAPHENE OXIDE; SERS; PESTICIDES; DELIVERY; HG(II); SENSOR
subject category
Spectroscopy
authors
Fernandes, T; Martins, NCT; Daniel-da-Silva, AL; Trindade, T
our authors
Ana Luísa Daniel da Silva
Principal Researcher
João Tiago Moniz Fernandes
PhD Student
Natércia da Conceição Tomé Martins
Junior Researcher
Tito Trindade
Full professorProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
T.F. thanks the Fundacao para a Ciencia e Tecnologia (FCT) for the PhD grant SFRH/BD/130934/2017. N.C.T.M. is funded by national funds (OE), through FCT-Fundacao para a Ciencia e Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by the law 57/2017, of July 19. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). We thank Carlos O. Amorim and Joao S. Amaral for the help provided during the magnetic measurements.