| Capillary electrophoresis(CE),which is also called high performance capillary electrophoresis(HPCE) or capillary electric separation method(CESM),is a new separation technique which was established and quickly developed in early 1980s.It's a combination of classic electrophoresis and modern micro-column separation technology,which is a great development in analytical chemistry field.So far,CE has been widely used in many fields including chemistry,life science,pharmaceutical and biomedical analysis,environment analysis,etc,due to its advantages in high separation power,short analysis time,small sample and reagent consumption and simplicity.Capillary electrophoresis with amperometric detection(CE-AD) is an important branch of CE.It's especially effective in the analysis of electroactive analytes.In this paper,CE-AD was employed for the determination of many electroactive ingredients in pharmaceutical and cosmetic products,and the results were satisfactory.This paper could be divided into four main parts as follows.1.PrefaceIn this chapter,the history of capillary electrophoresis technology was reviewed, and the fundamental theory,basic separation models and detectors of CE were introduced.At the same time,we narrated the present studies and applications of CE-AD in detail,as well as the goal and significance of this paper.2.Determination of Four Polyphenolic Active Ingredients from a Pharmaceutical Preparation by Capillary Zone Electrophoresis with Amperometric DetectionIn the second chapter,the simultaneous determination of four active ingredients from a pharmaceutical preparation called "Nao Xue Shuan Tablets",including ferulic acid,protocatechuic aldehyde,caffeic acid and protocatechuic acid,was performed by capillary zone electrophoresis with amperometric detection(CZE-AD).The effects of working electrode potential,pH and concentration of running buffer,separation voltage and injection time on CZE-AD were investigated.Under the optimum conditions,the four analytes could be perfectly separated within 18 min in a 20 mM borate buffer.A 300μm diameter carbon-disc electrode had a good response at +0.95 V(versus SCE) for the four analytes.The response was linear over three orders of magnitude with detection limits(S/N=3) as low as 10-8 or 10-9 g/mL for the analytes. The assay results were satisfactory with recoveries in the range of 85.2～93.0%and RSDs less than 3.3%.3.Determination of Active Ingredients of Spatholobus Suberectus Dunn and Its Medical Preparations by Capillary Zone Electrophoresis with Amperometric DetectionThe third chapter was about the determination of active ingredients in Spatholobus Suberectus Dunn and its medicinal preparations by capillary electrophoresis with amperometric detection.A method based on CZE-AD was developed for the separation and determination of epicatechin,emodin,syringic acid, vanillic acid,rhein,and protocatechuic acid in Spatholobus Suberectus Dunn and its medicinal preparations.The effects of a working electrode potential,pH and concentration of running buffer,separation voltage,and injection time on CE-AD were investigated.Under the optimum conditions,the analytes could be separated in a 60 mM borate buffer(pH=9.0) within 26 min.A 300μm diameter carbon disk electrode had a good response at +0.95 V(vs.SCE) for all analytes.The response was linear over three orders of magnitude with detection limits(S/N=3) ranging from 5.0×10-8 g/mL to 2.0×10-7 g/mL for the analytes.The method had been successfully applied to the analysis of real samples,with satisfactory results.4.Determination of Parabens in Cosmetic Products by Capillary Zone Electrophoresis with Amperometric DetectionIn the fourth chapter,the simultaneous determination of methyl-(MP),ethyl-(EP), propyl-(PP) and butyl-paraben(BP) in cosmetic products was performed by capillary zone eletrophoresis with amperometric detection(CZE-AD).The effects of working electrode potential,pH and concentration of running buffer,separation voltage and injection time on CZE-AD were investigated.Under the optimum conditions,the four analytes could be perfectly separated within 15 min in a 50 mM sodium tetraborate buffer.A 300μm diameter carbon-disc electrode had a good response at +0.95 V (versus SCE) for the four analytes.The response was linear over three orders of magnitude with detection limits(S/N=3) as low as 1×10-6 mol/L to 9×10-7 mol/L for the analytes.The utility of this method was demonstrated by monitoring different kinds of cosmetics,and good results were obtained.The results demonstrated that capillary zone electrophoresis with amperometric detection was of high sensitivity,good repeatability and could be widely used in the rapid determination of electroactive analytes in real samples.
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