Solid-Phase Fluorescence Filter Effect: Toward Field and Ultrasensitive Detection of Iodine Speciation in Seawater

Abstract

On-site analysis of iodine and its speciation in seawater is important for the prediction of radioactive iodine contamination. However, current methods, both colorimetric and instrumental, cannot meet the recent demand for field analysis and an increased reliability of results. Herein, a solid-phase fluorescence filter effect (SPFFE) induced by iodine was found and further used to develop a ratiometric fluorescence paper analysis device (RFPAD) for the analysis of iodine and its speciation in seawater. The proposed SPFFE-based assay surpasses the sensitivity and interference limitations arising from a specific extinction coefficient and multiple absorbers during real sample analysis, yielding an ultralow limit of detection of 550 pM for iodine. In conjunction with a smartphone, a developed program, and a sensing platform, both field-sensitive detection and speciation analysis of iodine could be achieved. An RFPAD was successfully used for the field speciation analysis of iodine and iodate in the South China Sea, showing excellent anti-interference capability and retaining promising potential for warning about radioactive iodine contamination in the ocean.

Field Detection of Uranyl in Coastal Water of China Using a Portable Device via DNA Photocleavage

“…Currently, there is growing interest in low-cost and field analysis across various analytical fields. ,,− To achieve the on-site monitoring of uranyl, a portable and compact detection device was developed using 3D printing technology. The device was integrated with a smartphone platform, as shown in Figures A and S10–S13, which includes detailed schematics with miniature components.…”

Point-of-Care Platform Based on Solid-Phase Fluorescence Filter Effect for Urinary Iodine Testing in Children and Pregnant Women

“…To achieve quantitative and on-site detection, the acquired fluorescence images were processed in the RGB recognition, and calculations were performed with a Python-based program (details summarized in Supporting Information 13). The steps involved in smartphone-based detection are summarized as follows: taking an image, cropping the image, entering the image file name into the program, and running the program to output the RGB values and urinary iodine concentration. To ensure the accuracy of the results, the default program was designed to automatically avoid highlighting and shadow errors, which could output RGB and concentration values based on reading and averaging multiple pixels.…”

“…As a common type of radiative energy transfer, the fluorescence inner filter effect (IFE) based on absorption of the excitation and/or emission light of the fluorophore by the absorber has attracted much attention due to its flexibility and ease of construction. , However, the available IFE-based sensing generally operates in the liquid phase and its practical application is severely hampered by interference from the complex matrix . The solid-phase fluorescence filter effect (SPFFE) is a nonradiative energy transfer phenomenon that occurs between a solid-phase absorber and a solid-phase fluorophore, which can be achieved by the solid-phase IFE sensor. Besides, the target reacted with the IFE system via the headspace sampling way can alleviate the interference of the liquid matrix toward the fluorophore by the absorber and act as an enrichment. , In addition, ratiometric fluorescence generates different colors with characteristic hues rather than changes in color brightness, which reduces the environmental interference and enables sensitive detection of analytes. − …”

Nanomaterial-based probes for iodide sensing: synthesis strategies, applications, challenges, and solutions

“…In the literature, iodide-ion quantification is commonly conducted using well-established analytical techniques, such as carbon dot/gold nanocluster-based fluorescent colorimetric paper strip sensing, 19 electro-colorimetric gel-based sensing, 20 photoluminescence sensing, 3 and ratiometric fluorescence paper analysis. 21 Overcoming the limitations in iodide detection involves using optical sensors with heightened affinity and specific binding capacity for iodide. The real-time optical chemosensing of iodide ions in aqueous environments remains a dynamic and steadily advancing field in analytical science and supramolecular chemistry.…”