title: Surface-enhanced Raman scattering spectroscopy as a sensitive and selective technique for the detection of folic acid in water and human serum.
abstract: Surface-enhanced Raman scattering (SERS) is shown to give linear and sensitive concentration-dependent detection of folic acid using silver nanoparticles created via ethylene-diaminetetraacetic acid (EDTA) reduction. Optical detection by SERS overcomes the primary limitation of photodissociation encountered during the application of other shorter wavelength ultraviolet (UV)/near-UV techniques such as fluorescence based microscopy. The SERS approach in water-based samples was demonstrated and optimized using several longer wavelengths of excitation (514.5, 632.8, and 785 nm). Excitation in the green (514.5 nm) was found to achieve the best balance between photodissociation and SERS efficiency. Linear concentration dependence was observed in the range of 0.018 to 1 microM. The importance of folic acid in a clinical setting and the potential applications of this technique in a biological environment are highlighted. We demonstrate the potential to transfer this technique to real biological samples by the detection of folic acid in human serum samples by SERS.
authors.affiliation: Centre for Molecular Nanometrology, WestCHEM, University of Strathclyde, Glasgow, UK.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stokes
authors.forename: Eileen
authors.initials: E
authors.lastname: McBride
authors.forename: Clive G
authors.initials: CG
authors.lastname: Wilson
authors.forename: John M
authors.initials: JM
authors.lastname: Girkin
authors.forename: W Ewen
authors.initials: WE
authors.lastname: Smith
authors.forename: Duncan
authors.initials: D
authors.lastname: Graham
mesh_terms: D005492:Folic Acid / Q000097:blood*; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D012834:Silver; D005492:Folic Acid