A valuable visual colorimetric and electrochemical biosensor for porphyrin

Area of Science:

• Analytical Chemistry
• Materials Science
• Biochemistry

Background:

• Porphyrins are crucial biological molecules with diverse applications.
• Developing sensitive and selective detection methods for porphyrins is essential.
• Existing detection methods may lack sensitivity or require complex instrumentation.

Purpose of the Study:

• To develop a novel bifunctional biosensor for porphyrin determination.
• To utilize the specific binding of porphyrin with phosphorus for sensing.
• To offer both visual colorimetric and electrochemical detection capabilities.

Main Methods:

• Chemical modification of a gold electrode with phosphorus compounds to create active sites.
• Characterization of the modified electrode using electrochemical impedance spectroscopy (EIS).
• Formation of a P(V)-porphyrin complex and observation of colorimetric and spectroscopic changes.

Main Results:

• The bifunctional sensor demonstrated high affinity for porphyrin, forming a 1:1 complex.
• Visual colorimetry detected porphyrin at 1.0×10⁻⁶ M, with a color change from burgundy to dark green.
• Electrochemical detection using EIS achieved a lower detection limit of 3.0×10⁻⁸ M.
• Successful determination of pheophytin in spinach leaves confirmed the sensor's practical applicability.

Conclusions:

• A novel bifunctional biosensor for porphyrin detection was successfully developed.
• The sensor combines visual colorimetry and electrochemical methods for versatile analysis.
• The demonstrated facility and effectiveness highlight its potential for quantitative porphyrin analysis.