title: Superhydrophobic-oleophobic Ag nanowire platform: an analyte-concentrating and quantitative aqueous and organic toxin surface-enhanced Raman scattering sensor.
abstract: The 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 10(3)-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.
authors.affiliation: Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , 50 Nanyang Avenue, Singapore 637371.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.forename: Hiang Kwee
authors.initials: HK
authors.lastname: Lee
authors.forename: In Yee
authors.initials: IY
authors.lastname: Phang
authors.forename: Choon Keong
authors.initials: CK
authors.lastname: Lee
authors.forename: Xing Yi
authors.initials: XY
authors.lastname: Ling
mesh_terms: D005506:Food Contamination / Q000032:analysis; D005524:Food Technology / Q000295:instrumentation / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D053770:Nanowires / Q000737:chemistry*; D009284:Naphthols / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014227:Triazines / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D009284:Naphthols; D009930:Organic Chemicals; D014227:Triazines; D014867:Water; D012834:Silver; C024336:1-phenylazo-2-naphthol; C011907:melamine