Influence of polarization of SERS-active surface on SERS spectra of creatinine

Abstract

Creatinine (CRN) is one of the most significant endogenous metabolites, and its concentration in human body fluids (urine, blood) can be used to assess impaired renal function and metabolic disorders. An electrospectral technique based on the combination of surface-enhanced Raman spectroscopy and electrochemical analysis (EC-SERS) was optimized to perform quick detection of CRN. A copper-based SERS substrate was used as the working electrode that allows for significant reduction of the costs of EC-SERS assay (compared to the assays with noble-metal based substrates). The use of the polarization of the SERS-active electrode and the adjustment of the pH of the electrolyte solution enable significant increase of the CRN signal intensity and cleaning the SERS substrate surface allowing for its reuse. Additionally, an analysis of the current-voltage characteristics allowed evaluating the possible effect of electrochemical transformations of CRN molecules on their SERS signal. Correction of pH value also leads to changing the profile of the EC-SERS signal due to the conversion of CRN to creatine in alkaline medium and the balance of protonated and deprotonated forms of CRN in neutral and acidic media. Finally, EC-SERS detection of CRN was carried out in a sample of real human urine using optimized protocol.
The work was supported by the Scholarships of the President of the Russian Federation to young scientists and graduate students (SP-1115.2021.4).

Speaker

Natalia E. Markina
Saratov State University
Russia

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