SERS-based error calibration of a TMB-H₂O₂ colorimetric system.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Biomedical Assays

Background:

• The 3,3',5,5'-tetramethylbenzidine (TMB)-H2O2 system is a common colorimetric method.
• Its accuracy is limited by environmental factors affecting TMB oxidation and spectral measurements.
• Existing methods using UV-vis or Raman spectra are prone to errors.

Purpose of the Study:

• To develop a surface-enhanced Raman spectroscopy (SERS)-based error calibration method.
• To improve the accuracy of the TMB-H2O2 colorimetric system.
• To provide a new approach for biomedical applications like ELISA.

Main Methods:

• Utilized surface-enhanced Raman spectroscopy (SERS) for TMB oxidation analysis.
• Monitored specific Raman peaks of TMB at 1189, 1335, and 1609 cm-1 under 633 nm laser excitation.
• Correlated the presence or absence of these peaks with the oxidation phase (single-electron vs. two-electron).

Main Results:

• Identified distinct Raman peaks in the single-electron oxidation phase that disappear in the two-electron phase.
• The SERS-based calibration method significantly improved the accuracy of the TMB-H2O2 colorimetric system by over 15%.
• Demonstrated the feasibility of using SERS for real-time monitoring of TMB oxidation.

Conclusions:

• SERS provides a robust method for error calibration in TMB-H2O2 colorimetric assays.
• This approach enhances the reliability of colorimetric measurements by accounting for oxidation process variations.
• The SERS-based TMB-H2O2 error calibration method holds promise for advancing ELISA and other biomedical diagnostics.