Abstract
A new, simple photo-deposition method of silver nanoparticles induced by laser inside a fused-silica capillary is described and tested. Silver nanoparticles are immobilized using Ar-ion laser beam of a wavelength of 488nm and power of 3.6mW for 60min. The photodeposited compact spot of a size of ∼10μm is temporary and spatially stable and resistant to a hydrodynamic flow. The deposit has very good properties for surface-enhanced Raman scattering and serves well for detection in capillary electrophoresis. The advantage of this approach is that neither the silver nanoparticles nor the chemicals for their preparation are components of the background electrolyte during the electrophoretic separation. Thus, the substrate formation and separation of analytes are two independent processes and can be performed under their optimum conditions. The zone broadening due to the sorption of analytes on the immobilized nanoparticles can be significantly reduced by an addition of 20% solution of methanol. The efficiency of capillary electrophoresis and detection selectivity of surface-enhanced Raman scattering induced by He–Ne laser at 632.8nm is demonstrated by the 3D electropherograms of rhodamines 123 and B as model samples. The limits of detection of about 49 and 150fmol (1 and 2μM) have been reached for rhodamine B and 123, respectively.
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