Fabrication of liquid–liquid self-assembled Ag array on disposable screen-printed electrodes and their application in the identification and analysis of adsorption behavior of organic carboxylates through in-situ electrochemical surface-enhanced Raman scattering

A disposable Ag array@screen-printed electrode (SPE) was fabricated for the identification and analysis of adsorption behavior of organic carboxylates in in-situ electrochemical surface-enhanced Raman scattering (EC-SERS). Liquid–liquid self-assembled Ag arrays were prepared and modified onto the SPE to induce the SERS enhancement effect. The Ag arrays were characterized by transmission electron microscopy and UV-Vis spectroscopy and the SERS performance of the sensor were explored. The adsorption behavior and orientation of citrate, tartrate, and malate on the Ag array@SPEs under controlled potential for appropriate durations was studied. Results showed citrate, tartrate, and malate can be concentrated on the Ag array@SPE surface with an effective amplification of SERS signal under a potential of 0.100 V vs. Ag/AgCl for 400 s, 450 s and 350 s. The carboxylates were identified on the basis of the vibrational assignments of characteristic SERS bands. Citrate, tartrate and malate adsorbed mainly in claw, parallel and vertical forms on the sensor under the controlled potential. Therefore, the Ag array@SPEs has the potential applications to the rapid and sensitive determination of these analytes and the identification of intermediates in EC-SERS.