Anal Sci. 2025 Sep 9. doi: 10.1007/s44211-025-00846-1. Online ahead of print.
ABSTRACT
Surface-enhanced Raman scattering (SERS) is a powerful analytical technique; however, its quantitative application has been limited by the instability of substrates and significant signal fluctuations. In this study, we demonstrated that 4-aminobenzenethiol (4-ATP) can be quantitatively detected through statistical analysis of SERS signal intensity distributions obtained using citrate-stabilized AuNPs, biotin-functionalized AuNPs, and gold nanoparticle (AuNP)-bound polystyrene (PS) microparticles. Raman spectra obtained in bulk aqueous solution under static conditions showed that the detection sensitivity of 4-ATP using AuNP-bound PS microparticles was approximately twice that achieved with citrate-stabilized AuNPs or biotin-modified AuNPs. Furthermore, the detection sensitivity of 4-ATP was enhanced by introducing AuNP-bound PS microparticles into a microfluidic chip and delivering an aqueous 4-ATP solution under controlled flow conditions. Analysis of the flow rate dependence of SERS signal intensity revealed that the optimal detection sensitivity for 4-ATP was achieved at a flow rate of 0.66 μL·min⁻1, with a corresponding detection limit of 1.9 μM under these conditions. These results demonstrate that AuNP-bound PS microparticles introduced into the microfluidic chip serve as efficient SERS substrates, enabling highly sensitive and quantitative detection under flow conditions.
PMID:40924288 | DOI:10.1007/s44211-025-00846-1
