[Show abstract][Hide abstract] ABSTRACT: Some categories of compounds, including quinones, coumarins, flavins, and xanthene dyes, were found to produce strong chemiluminescence (CL) signals with luminol in sample solution under the irradiation of light emitting diodes (LED) with proper wavelengths. Based on this phenomenon, a compact photochemical reactor was constructed to develop a novel LED induced CL detector for high performance liquid chromatography (HPLC). The effects of related parameters including LED wavelength, luminol concentration, flow rate, pH, and eluents of HPLC were investigated in detail. Under the optimized conditions, the limits of detections (LODs) were in the range of 0.2-80 ng mL(-1). The applications and accuracy of the proposed method were validated by analyzing food samples such as milk powder, beer, candy and beverage with satisfactory results.
No preview · Article · Oct 2009 · Journal of Chromatography A
[Show abstract][Hide abstract] ABSTRACT: A new capillary zone electrophoresis method with laser-induced fluorescence detection is presented for the determination of
noradrenaline (NA) and dopamine (DA). The fluorescent reagent, 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein, which readily
reacts with amine group under mild conditions, was initially used to label the two compounds. Under optimized separation and
labeling conditions, linear relationship between peak area and analyte concentration was obtained with high sensitivity (nM
level). The applicability of the method for complex sample analysis was validated by determining the two compounds in a human
serum and an herb, Portulaca oleracea L with recoveries ranging from 89% to 102%.
No preview · Article · Sep 2009 · Microchimica Acta
[Show abstract][Hide abstract] ABSTRACT: Derivative spectrophotometry is introduced for the quantification of overlapping peaks in capillary electrophoresis. The application
for resolving overlapping peaks is tested using eleven benzoic acids as examples. Compared with common spectrophotometric
detection, the derivative mode has slightly lower reproducibility, comparable sensitivity but much higher separation efficiency
as the peak is much sharpened. Derivative spectrophotometry offers the advantages of reagent-, time- and labor-saving since
only few optimizations of separation conditions for normal CE are essential to make the peaks partly baseline-resolved. Analysis
of real samples using the method was also performed and results obtained give evidence of the potential for improved quantification
without loss in accuracy.
No preview · Article · Feb 2009 · Microchimica Acta