Study On Application Of Capillary Electrophoresis In Metabolomics Of Corns

Capillary electrophoresis (CE) has been applied in many fields owing to its advantages ofhigh separation efficiency and fast speed. However, the detection sensitivity of CE is greatlylimited due to the small injection volume and the short optical path length. Currently, in order toimprove the detection sensitivity of CE, various sample concentration methods have beeninvestigated and developed. The metabolites of corns were analyzed by CE coupled withon-line concentration methods. The major content is described as follows:1. Two on-line concentration methods, namely field-enhanced sample stacking and dynamicpH junction, were utilized to improve the detection sensitivity. When field-enhanced samplestacking method was used, nine water-soluble vitamins were focused and separated baseline.When dynamic pH junction method was used, only nicotinic acid and folic acid were focused.The limits of detection of the vitamins were from 6 to 119 ng/mL (2.7×10^-8 to 53.4×10^-8 M)based on the signal-to-noise ratio of 3 and the relative standard deviations of migration time andpeak area for each vitamin (1μg/mL) were less than 3.5% using the field-enhanced samplestacking as an on-line concentration method. The developed method was applied to the analysisof water-soluble vitamins in corns and two vitamins, pyridoxine hydrochloride and nicotinicacid, were detected. The estimated concentration of them were 2.5±0.11μg/g-6.67±0.17μg/g and 0.25±0.01μg/g-0.67±0.08μg/g respectively. The recoveries of them were 87%-106% and RSD were less than 6.81%.2. Two on-line concentration methods, namely field-enhanced sample stacking and dynamicpH junction, were utilized to improve the detection sensitivity. Seven purine bases andpyrimidine bases were focused and separated baseline using two methods. Comparing tofield-enhanced sample stacking, dynamic pH junction was more suitable for the concentrationof purine bases and pyrimidine bases since the sensitivity enhancement was higher usingdynamic pH junction. The limits of detection of purine bases and pyrimidine bases were from0.8 to 39.8 ng/mL(0.59×10^-8 to 35.51×10^-8 M)based on the signal-to-noise ratio of 3 and therelative standard deviations of migration time and peak area for each purine base andpyrimidine base (1μg/mL) were less than 3.69% using the dynamic pH junction as an on-lineconcentration method. The developed method was applied to the analysis of purine bases and pyrimidine bases in corns.