A surface enhanced Raman scattering probe for highly selective and ultra sensitive detection of iodide in water and salt samples

Analyst. 2013 Feb 21;138(4):1195-203. doi: 10.1039/c2an36293g.

Abstract

Iodine is a biophilic and essential trace element for all life and especially for vertebrates, which require it to produce indispensable thyroid hormones in their thyroid glands. As a result, the adequate measurement of iodine in water and food samples is crucial to lead a healthy life. Motivated by its importance, this is the first time in the literature that the highly selective and ultra sensitive (30 ppt limit) surface enhanced Raman scattering (SERS)-based detection of iodide ions (I(-)) from environmental and food samples has been reported. The desired sensitivity and selectivity has been achieved by measuring the change in the SERS intensity originating from Rh6G-adsorbed 30 nm gold nanoparticles (GNPs) upon the addition of I(-). The strong chemical affinity offered by I(-) towards the gold surface results in extra negative charge being deposited on it. As a result, the GNP surface attracts a greater number of positively charged Rh6G molecules and induces a marked increase in the number of hot spots through aggregation, providing a significant enhancement of the Raman signal intensity. The oxidation of I(-) to molecular iodine (I(2)) by hydrogen peroxide (H(2)O(2)) is employed for the successful screening of the bromide ion (Br(-)) which shows substantial interference at higher concentrations.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Iodides / analysis*
  • Metal Nanoparticles / chemistry
  • Salts / analysis*
  • Spectrum Analysis, Raman / methods*
  • Surface Properties
  • Water / analysis*

Substances

  • Iodides
  • Salts
  • Water