Rational Calibration Strategy for Accurate and Sensitive Colorimetric Detection of Iodide and l-Thyroxine Based on Gold Triangular Nanoplates

Abstract

We developed a sensitive and accurate colorimetric method to detect iodide (I–) and l-thyroxine by etching gold triangular nanoplates (AuTNPs) in the presence of H2O2. The morphological changes of AuTNPs resulted in vivid color variations of the nanoprism dispersion, accompanied by a blue shift of the in-plane localized surface plasmon resonance (LSPR) peak, enabling visual and photometric sensing. To improve the accuracy and the linear range, the overlapping out-of-plane and in-plane LSPR peaks of the AuTNPs were deconvoluted, and a new calibration model was established by plotting the square of the in-plane LSPR wavelength shift against the concentration of the analytes. Under optimum conditions, the limits of detection (LODs) for iodide reached 1 μM and 50 nM by the naked eye and photometry, respectively, and the corresponding LODs for l-thyroxine were 200 and 13.7 nM. Importantly, improved accuracy and linear range were obtained by the new data processing strategy. The method was applied in detecting iodide in tap and drinking water samples and l-thyroxine in pharmaceutical tablets, indicating its potential for real sample analysis.

Cellphone-Aided Attomolar Zinc Ion Detection Using Silkworm Protein-Based Nanointerface Engineering in a Plasmon-Coupled Dequenched Emission Platform

“…Furthermore, it is worth emphasizing that the SPCE enhancements reached a maximum of >300-fold for a 30 min UV-exposed sample that displayed unique cubic nanogeometry. Anisotropic Au nanostructures (such as cubes, rods, and triangular plates) have been extensively investigated for transdisciplinary applications encompassing photonics, biosciences, materials chemistry, and quantum technologies. − Earlier reports evince a significant contribution of longitudinal modes in NP solution toward MEF by augmenting the scattering efficiency (of the overall extinction = absorbance + scattering). , In this perspective, the longitudinal modes observed in Figure a for the same sample aids in significant scattering (vis-à-vis absorption loss), thereby further augmenting the fluorescence emission. , We also anticipate the effects of coupled Au nanocubes to give substantial increase in the intensity of the longitudinal mode for the 30 min UV-exposed sample in line with the earlier literature. , This is attributed to the interplasmonic coupling in the interstitial junctions between adjacent Au nanocubes. Overall, the augmented SPCE enhancements with the use of AuNPs can be attributed to the following factors working in synergy at the nanointerface: (i) nanocubic geometry of AuNPs that lead to ultraamplification of EM field intensity.…”

Dual colorimetric sensing of ascorbic acid and thyroxine using Ag–EGCG–CTAB via a DFT approach

“…Lower thyroxine levels in the body can cause hypothyroidism directing to a lower metabolic rate, memory problems, infertility, etc., whereas higher thyroxine levels may result in goiter, weight loss, and several other afflictions. 13 Therefore, it is necessary to detect these compounds at the micromolar level in different food sources and drugs.…”

“…The sensing of TH can be done by etching with Au triangular plates in the presence of H 2 O 2 with a detection limit of 1 mM, which was further utilized in real sample analysis. 13 Antibody-labeled AuNP immune-sensors can sense TH up to 9.11 pg ml À1 . 17 Herein, we report a simple, green, cost-effective and timesaving colorimetric method for sensing both AA and TH using AgNPs synthesized from Elsholtzia blanda Benth.…”

“…, whereas higher thyroxine levels may result in goiter, weight loss, and several other afflictions. 13 Therefore, it is necessary to detect these compounds at the micromolar level in different food sources and drugs.…”

“…The sensing of TH can be done by etching with Au triangular plates in the presence of H 2 O 2 with a detection limit of 1 μM, which was further utilized in real sample analysis. 13 Antibody-labeled AuNP immune-sensors can sense TH up to 9.11 pg ml −1 . 17 …”