A new approach for the detection of a nonfluorescent compound by CE-resonance Raman spectroscopy based on the sweeping-MEKC mode.
A CE-resonance Raman spectroscopy (CE-RRS) method based on MEKC and sweeping-MEKC modes is described. A nonfluorescent compound, malachite green (MG), and a doubled Nd:YAG laser (532 nm, 300 mW) were selected as model compound and light source, respectively. In order to carry out a quantitative analysis of MG, a monochromator (effective bandwidth, 0.4 nm) was used to collect the specific Raman line at 1616 cm(-1) (N-phi and C-C stretch, corresponding to 582 nm when the wavelength of the exciting source was 532 nm). As a result, the LOD for MG was 10 ppm, based on the MEKC/RRS mode. This could be improved to 5 ppb when the sweeping-MEKC/RRS mode was applied. Furthermore, with the addition of nano-size silver colloids to the CE buffer the detection limits can be further improved, but the data obtained with surface-enhanced resonance Raman spectroscopy (SERRS) are less useful for quantitative purposes.
Tsai
Chih-Hsin
CH
Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
Chan
Po-Han
PH
Lin
Cheng-Huang
CH
Chang
Ta-Chau
TC
Chia
Chih-Ta
CT
D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003102:Colloids / Q000737:chemistry; D004396:Coloring Agents / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D007834:Lasers; D012394:Rosaniline Dyes / Q000032:analysis; D012834:Silver / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
D003102:Colloids; D004396:Coloring Agents; D012394:Rosaniline Dyes; C005095:malachite green; D012834:Silver