Highly Sensitive and Selective Determination of Iodide and Thiocyanate Concentrations Using Surface-Enhanced Raman Scattering of Starch-Reduced Gold Nanoparticles

Abstract

In this report, we propose a novel technique for the determination of the concentrations of iodide and thiocyanate by surface-enhanced Raman scattering (SERS) of starch-reduced gold nanoparticles. Starch-reduced gold nanoparticles show an intrinsic Raman peak at 2125 cm(-1) due to the -C≡C- stretching mode of a synthesized byproduct. Because of the high adsorptivity of iodide on a gold surface, the intensity of the SERS peak at 2125 cm(-1) decreases with an increase in the iodide concentration. Thiocyanate also strongly adsorbs on a gold surface, and a new peak appears at around 2100 cm(-1), attributed to the -C≡N stretching vibration in a SERS spectrum of starch-reduced gold nanoparticles. These two peaks were successfully used to determine the iodide and thiocyanate concentrations separately, even in their mixture system. The detection limit of this technique for iodide is 0.01 μM with a measurement range of 0.01-2.0 μM, while the detection limit of this technique for thiocyanate is 0.05 μM with a measurement range of 0.05-50 μM. This technique is highly selective for iodide and thiocyanate ions without interference from other coexisting anions such as other halides, carbonate, and sulfate.

A Novel Sensor for Sensitive and Selective Detection of Iodide Using Turn-on Fluorescence Graphene Quantum Dots/Ag Nanocomposite

“…For example, deficiency of dietary iodine or abnormal metabolism of iodine could cause goiter, hypothyroidism, and hyperthyroidism. 1,2 Moreover, deficiency of dietary iodine could lead to developmental defects in extreme conditions. Therefore, the determination of iodide ions is valuable for epidemiological studies of iodine supplementation, particularly in diagnosing and controlling iodine deficiency.…”

A Sensitive Silver Nanorod/Reduced Graphene Oxide SERS Analytical Platform and Its Application to Quantitative Analysis of Iodide in Solution

“…The linear range is 0.008-1.5μmol/L, with a regress equation of ΔI I =896 C I +52 and a detection limit (3σ) of 4 nmol/L I − . At present, several methods including spectrophotometry, fluorescence, high-performance liquid chromatography (HPLC), and mass spectrometry (MS) [57][58][59][60][61][62][63] have been reported for determination of iodine ion. HPLC and MS are sensitive, but both operations are complicated, the equipment costs and operation costs are very high.…”

PolyA-tailed and fluorophore-labeled aptamer-gold nanoparticle conjugate for fluorescence turn-on bioassay using iodide-induced ligand displacement

“…2 ) that have strong affinity for Au (Chen et al, 2009;Pienpinijtham et al, 2011;Zhang et al, 2012c), were first proposed as the ligand displacing reagents to release the attached polyA-tailed DNA from AuNP surface. Based on this novel finding and the employment of polyA-tailed, fluorophore-labeled apt29-AuNP (Fapt29-polyA-AuNP) conjugate and Apt15-conjugated magnetic beads (Apt15-MBs), we developed a cost-effective and sandwichtype fluorescence turn-on aptasensing platform for highly sensitive and specific TB detection, which eliminated the use of thiolated aptamer and thiol-containing displacing reagents.…”