A Novel Morpholine-Based Rhodamine Fluorescent Chemosensor for the Rapid Detection of Hg²⁺ Ions

Abstract

<jats:p>A novel rhodamine-based receptor bearing a morpholine (RDM) was developed as a fluorescent chemosensor with high selectivity toward Hg<jats:sup>2+</jats:sup>. After the addition of Hg<jats:sup>2+</jats:sup> to RDM, the color of the solution changed from colorless to pink, and the new absorption band appears at 580 nm. The fluorescent of RDM appears to orange color in the presence of Hg<jats:sup>2+</jats:sup>. Upon the addition of Hg<jats:sup>2+</jats:sup>, ring-opening of the corresponding spirolactam gives rise to fluorescence, and a 1:1 metal-ligand complex formed.</jats:p>

Application of Nanotechnology in Biomedicine

“…Zero-dimensional nanomaterials refer to tiny particles whose three dimensions are nanoscale, including clusters, quantum dots, nanoparticles, etc. [11][12]. The diameter of the clusters is usually no larger than 1 nm.…”

Recent Developments in Fluorescent Materials for Heavy Metal Ions Analysis From the Perspective of Forensic Chemistry

“…Rhodamine B is widely used in heavy metal ions detection with high stability, large molar extinction coefficient, and high fluorescence quantum yield. Many molecular structures ( Figure 1A ) based on rhodamine B are designed and synthesized for more sensitive and more adapted to the sample matrix for Hg 2+ recognition (Rui et al, 2016 ; Duan et al, 2017 ; Liu and Qian, 2017 ; Venkatesan et al, 2017 ; Fang et al, 2018 ; Park et al, 2019 ; Rasheed et al, 2019 ), and the proposed mechanism of Hg 2+ biosensing is in Figure 1B . A rhodamine B-derived Schiff base has been designed for the combined detection of Cu 2+ , Al 3+ , and Fe 3+ , and its sensing behavior toward various metal ions was investigated in semi-aqueous media (Gupta et al, 2016 ).…”

“…The sensor showed significant fluorescence response accompanied by a color change from colorless to pink emission to Fe 3+ over a wide range of metal ions, while just colorimetric response toward Cu 2+ and Al 3+ . Park et al ( 2019 ) fabricated the paper test strips based on rhodamine-morpholine probe for Hg 2+ detection, a limit of detection (LOD) of 4.8 μM within 1–2 min treatment. Liu and Qian ( 2017 ) produced a fluorescent sensor based on the naphthalimide-rhodamine dye encapsulated in silica nanoparticles to improve its water solubility and biocompatibility, and the ratiometric fluorescent sensor realized quantitative detection of Hg 2+ with a LOD of 2.72 μM within <2 s in complex sample analysis and bioapplications.…”

A novel coumarin-derived dithioacetal chemosensor for trace detection of Hg2+ in real water samples

“…Long-lasting uptake of high levels of mercury can lead to serious health problems, such as neurological damage, effects on the immune system, Minamata disease, muscle weakness, motion disorders, and chronic diseases. [5][6][7] Therefore, the development of methods for efficiently detecting Hg 2+ is of great significance.…”