Samarium-Based Turn-Off Fluorescence Sensor for Sensitive and Selective Detection of Quinolinic Acid in Human Urine and Serum

Abstract

Quinolinic acid (QA) is an index for some diseases, whose detection is of importance. This work presents a samarium metal–organic framework (Sm-MOF) containing 5-sulfoisophthalate ligand (SIP3–). The fluorescence of Sm-MOF integrates the emission at 339 nm from the SIP3– ligand and four characteristic 4G5/2 → 4H j (j = 5/2, 7/2, 9/2, and 11/2) transitions at 559, 596, 642, and 701 nm from Sm(III). Sm-MOF as a turn-off fluorescence sensor to QA exhibits high sensitivity, selectivity, and durability. The fluorescence quenching response to QA shows a linear relationship of I 0/I = 0.00496·C QA + 1.12474 in the QA concentration of 0–500 μM and a limit of detection calculated as 4.11 μM. Sm-MOF shows the structural and fluorescent stabilities in five quenching–recovery cycles. The recoveries of close to 100% in human urine and serum indicate high reliability. The paper-based Sm-MOF sensor displays a rough QA quantitative analysis by recognizing red values in the on-site QA detection.

A Water‐Stable Europium Metal‐Organic Framework as a Turn‐Off Fluorescence Sensor for Ascorbic Acid Detection in Human Serum

“…Absorption competition, structural destruction, and fluorescence resonance energy transfer are the three main fluorescence quenching mechanisms [29,52] The PXRD patterns of Eu-NDBC immersed in AA or at pH = 4-11 are the same as the simulated one, demonstrating structural destruction is not the reason (Figures S7 and S8). The overlapped UV-vis bands reveals the mechanism of absorption competition between the NDBC 2À ligand and AA.…”

“…The overlapped energy band suggests the competition between NDBC 2− and AA in absorbing excitation energy as AA forms weak interactions with Eu(III) through hydroxyl groups. It leads to blocking the energy transmission path from NDBC 2− to Eu(III), making stronger emissions from ILCT and the fluorescence quenching of 5 D 0 → 7 F j transfers of Eu(III) [28–29] …”

“…7 F j transfers of Eu(III). [28][29] The plot of I/I 0 vs pH reveals the influence of pH on fluorescence of Eu-NDBC (Figure 2d). As pH = 4-10, I/I 0 values fluctuate around 30 %, showing I 613 are quenched 64-78 %.…”

Fluorescence sensing and device fabrication with luminescent metal–organic frameworks

“…9). 81 Upon addition of QA, the strong emission of charge transfer within the ligand at about 361 nm is retained, while the characteristic emission of Sm( iii ) is quenched. The luminescence color of its suspension also changed from red to blue.…”

Functionalized 2D Germanene and Its Derivatives for Electrochemical Detection of Gut-Derived Metabolites in Human Serum

“…Recently, abnormal levels of some gut-derived metabolites, kynurenic acid (KA) and quinolinic acid (QA) were found to be associated with neurodegenerative disorders like dementia, Alzheimer's and Parkinson's diseases [1,2]. These neurological disorders have affected more than 1 billion people worldwide and resulted in close to 7 million deaths yearly [3].…”