CDs–MnO₂–TPPS Ternary System for Ratiometric Fluorescence Detection of Ascorbic Acid and Alkaline Phosphatase

Abstract

Manganese dioxide (MnO 2 ) nanosheet-based fluorescence sensors often use oxidase-like activity or wide absorption spectrum for detection of antioxidants. In those strategies, MnO 2 nanosheets were reduced to Mn 2+ by antioxidants. However, few strategies emphasize the role of Mn 2+ obtained from MnO 2 reduction in the design of the fluorescence sensor. Herein, we expanded the application of a MnO 2 nanosheet-based fluorescence sensor by involving Mn 2+ in the detection process using ascorbic acid (AA) as a model target. In this strategy, carbon dots (CDs), MnO 2 nanosheets, and tetraphenylporphyrin tetrasulfonic acid (TPPS) comprise a ternary system for ratiometric fluorescence detection of AA. Initially, CDs were quenched by MnO 2 nanosheets based on the inner filter effect, while TPPS maintained its fluorescence intensity. After the addition of AA, MnO 2 nanosheets were reduced to Mn 2+ so that the fluorescence intensity of CDs was recovered and TTPS was quenched by coordination with Mn 2+ . Overall, AA triggered an emission intensity increase at 440 nm for CDs and a decrease at 640 nm for TPPS. The ratio intensity of CDs to TPPS ( F 440 / F 640 ) showed a good linear relationship from 0.5 to 40 μM, with a low detection limit of 0.13 μM for AA detection. By means of the alkaline phosphatase (ALP)-triggered generation of AA, this strategy can be applied for the detection of ALP in the range of 0.1–100 mU/mL, with a detection limit of 0.04 mU/mL. Furthermore, this sensor was applied to detect AA and ALP in real, complex samples with ideal recovery. This novel platform extended the application of MnO 2 nanosheet-based fluorescence sensors.

Halogen Doping to Control the Band Gap of Ascorbic Acid: A Theoretical Study

“…Ascorbic acid (vitamin C) is a crucial natural organic compound that is present in the majority of fruit and some specialized vegetables . It is an organic compound with the chemical formula C 6 H 8 O 6 that is chiral with six carbon atoms and has four stereoisomers .…”

Enhanced detection of ascorbic acid with cascaded fluorescence recovery of a dual-nanoquencher system

“…19 Hence, the quantitative determination of AA is signicant for disease prevention and food safety. [32][33][34][35] Herein, a signal amplication strategy has been designed to detect AA on the basis of an analyte-triggered cascade system composed of dual nanoquenchers (MnO 2 nanosheets and AuNPs). The background signal is remarkably minimized ascribed to synergistic quenching effect of MnO 2 nanosheets and AuNPs.…”

“…19 Hence, the quantitative determination of AA is significant for disease prevention and food safety. 32–35…”

Supramolecular Host‐Guest Interaction‐Driven Electrochemical Recognition for Pyrophosphate and Alkaline Phosphatase Analysis

“…[14,15] Often, ALP and PPi tend to appear in biological system simultaneously and can be analyzed as a close associate team. [16,17] Up to now, varied methods have been designed for PPi and ALP detection, such as colorimetry, [18] fluorescence, [19] chemiluminescence, [20] and surface-enhanced Raman scattering. [21] Among these, some metal ions (including Zn(II), Cu(II), etc.)…”