An exploration of surface enhanced Raman spectroscopy (SERS) for in situ detection of sulfite under high pressure.

Highlights • Silver nanoparticles are fabricated directly on the surface of the diamond anvil as the SERS substrate. • The low detection limit of sulfite could reach up to 5 μmol/L in the diamond anvil cell. • The intensity of the two vibration modes showed good linearity under high pressure. • The SERS spectra of SO 3 2− were obtained at different pressure ranging from 54 MPa to 330 MPa. Abstract In this work, silver nanoparticles film was directly fabricated on the surface of the diamond anvil as SERS active substrate for the first time by using a simple and convenient method. With this approach, the SERS spectrum of sulfite was obtained with a detection limit of 5 μmol/L in diamond anvil cell (DAC) at ∼50 MPa. The SERS signal intensity of the two main vibration modes, ν sym S O and δ sym O S O, showed good linearity with the Na 2 SO 3 concentrations in the range from 5 to 40 μmol/L under high pressure. The linear correlation coefficients were 97.67% and 96.08%, respectively. The effects of pressure on the SERS intensity and Raman shift of the two modes were also studied. The SERS intensity dropped with the increase of pressure and the two main vibration modes shifted to high wave-number when the pressure increased in the pressures ranging from 54 MPa to 330 MPa. The experiments indicate that this method is rapid, convenient and sensitive in detecting sulfite at high pressures. It can be developed as an effect in situ method to detect sulfite in the process of high pressure reaction. [ABSTRACT FROM AUTHOR]