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Download fileSuperhydrophobic-Oleophobic Ag Nanowire Platform: An Analyte-Concentrating and Quantitative Aqueous and Organic Toxin Surface-Enhanced Raman Scattering Sensor
journal contribution
posted on 2014-10-21, 00:00 authored by Xing Li, Hiang Kwee Lee, In Yee Phang, Choon
Keong Lee, Xing Yi LingThe ultratrace detection and quantification
of toxins in both water
and organic liquids remains a challenge due to the random spreading
and dilution of liquids on substrate-based sensors, especially for
organic liquids with low surface tension. Herein, we fabricate a superhydrophobic-oleophobic
(SHP-OP) 3D Ag nanowire mesh-like surface-enhanced Raman scattering
(SERS) platform to overcome the random spreading issue, demonstrating
ultratrace toxin sensing in both water and organic liquid. Our SHP-OP
SERS platform is able to concentrate analyte solutions in water and
toluene to 100-fold and 8-fold smaller areas, respectively, as compared
to its omniphilic counterparts. The synergy of analyte-concentrating
ability and intense SERS-enhancing properties on our SHP-OP SERS platform
enables quantitative and ultratrace detection of melamine and Sudan
I down to 0.1 fmol in water and toluene, respectively, using just
1 μL of analyte solution. These detection limits are 103-fold lower than the regulatory limits, clearly indicating
our SHP-OP SERS platform as an appealing universal ultratrace toxin
sensor. The ultratrace detection of spiked melamine in liquid milk
down to 100 fmol also highlights the suitability of our SHP-OP SERS
platform for the sensing of food toxins in real samples.