Research on Ultrasensitive Detecting Method Based on Surface Enhanced Raman Scattering Effect

摘要

Surface enhanced Raman scattering (SERS) spectroscopy has been reported as an ultrasensitive detecting method. Adding salts is a main way to induce nanoparticles aggregation to obtain giant enhancement of Raman signal. However, this method needs more procedures and the adding salts may interfere the detection reaction. Here an effective and simple method is reported to enhance SERS effect of the aggregation of silver nanoparticles (Ag NPs) induced by the laser of 633 nm. Ag NPs were prepared by plasmon-mediated method. Surface plasmon band of Ag NPs is ～ 635 nm which could effectively absorb the 633 nm laser energy. When laser irradiating Ag NPs during the detection of Raman spectra, these Ag NPs gradually aggregated and SERS spectra of analytes (4-mercaptobenzoic acid, 4-MBA) were gradually enhanced. And enhancement factor of Raman spectra ～109 is obtained by this method. Due to the huge magnitude of SERS in the near infrared region (excitation wavelength 633 nm), this technique has the potential application in the field of biochemical tests.