A novel ratiometric colorimetric sensor for detecting hypochlorite and ascorbic acid based on cascade reaction

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Hypochlorite and ascorbic acid (AA) are vital in physiological processes.
• Accurate determination of these analytes is crucial for health monitoring.
• Existing detection methods may lack sensitivity or selectivity.

Purpose of the Study:

• To develop a novel ratiometric colorimetric sensing strategy for simultaneous determination of hypochlorite and AA.
• To utilize the catalytic properties of Fe3O4-MOF-5(Fe) for sensitive detection.
• To establish a platform for analyzing these analytes in complex samples.

Main Methods:

• A ratiometric colorimetric sensing strategy based on the oxidation and reduction of 3,3',5,5'-tetramethylbenzidine (TMB).
• Utilized Fe3O4-MOF-5(Fe) as a catalyst exhibiting peroxidase-like activity.
• Monitored absorbance changes at 652 nm and 450 nm for quantitative analysis.

Main Results:

• The sensor demonstrated a concentration-dependent ratiometric variation (A450/A652) for hypochlorite detection.
• Ascorbic acid (AA) reduced diazotized TMB, enabling its detection.
• Achieved low detection limits: 0.027 μM for hypochlorite and 0.677 μM for AA.
• The platform exhibited high sensitivity and selectivity due to specific reactions and catalyst activity.

Conclusions:

• A novel and effective ratiometric colorimetric sensing platform for hypochlorite and AA was successfully developed.
• The strategy leverages the catalytic oxidation-reduction of TMB mediated by Fe3O4-MOF-5(Fe).
• This method provides a sensitive, selective, and guidance for developing sensors for successive detection in complex samples.