ABSTRACT
In the present work, the electrochemical deposition of silver was investigated on a glassy carbon electrode from AgNO3 solutions in the presence of RTILs (1-butyl-3-methyl imidazolium nitrate, [bmim]NO3) additive by cyclic voltammetric technique, scanning electron microscope (SEM) and X-ray photon spectroscopy (XPS). For comparison, the electrodeposition of silver from [bmim]NO3-free AgNO3 solution was also investigated. The voltammograms showed that the cathodic peak potential shifted toward more negative potential and the cathodic peak current decreased when 5 x 10(-6) mol x L(-1) [bmim]NO3 was added into AgNO3 solutions. This indicated that [bmim]NO3 produced an inhibition of silver deposition, probably related to the adsorption of [bmim]NO3. SEM images showed that the uniform, shining electrodeposits of silver obtained in AgNO3 solutions were rather compact and that the size of silver grains decreased with the addition of [bmim]NO3 additive. The surface-enhanced Raman scattering (SERS) activities of silver deposits were measured by using methyl orange (MO) as the probe molecules. The strongly enhanced Raman scattering from the monolayer film of MO demonstrated that the as prepared silver particular film was SERS active. The enhancement factor was calculated to be up to 1.7 x 10(5) and 1.1 x 10(5) for silver film obtained in AgNO3 solutions with and without [bmim]NO3 additive, respectively.
ABSTRACT
Under incident light 514.5 nm, Raman scattering spectrum of trace contraband Heroin on finger with low concentration was investigated. It has been known that contraband Heroin has strong fluorescence background in its Raman scattering under visible excitation. By analyzing the sample surface and applying appropriate experimental method, the high signal-noise ratio quality and low fluorescence Raman spectrum was obtained. The result indicated that it would be much improved the Raman scattering spectrum by using slick Al slice as gasket for drugs and selecting proper area on the sample surface, controlling the incident light power. This work could provide a powerful method for detecting trace materials including drugs, explosives, deleterious material in forensic science.
