| Alkaloids are usually the biologically active compounds in many Chinese medicinal plants.However,it is very difficult to detect the alkaloids extracted from the plants due to the large energy consumption,complicated sample matrices and low extraction yield in traditional separation methods.In recent years,there are increasing interests in coupling high-efficient capillary electrophoresis separation(CE)with high-sensitive electrochemiluminescence detection(ECL)for alkaloids analysis and other complicated samples.At present,the developments of CE-ECL are still in its preliminary state,and especially the related methods for the separation and determination of active components in urines and plant extracts are popular and welcome.However,there are few reports on the ulitization of chemically modified electrodes(CMEs)in the field of CE-ECL detection although the resolution and sensitivity can be improved by use of CMEs.Therefore,in this paper,a microdisk platinum electrode modified with Europinum(Ⅲ)-doped Prussian Blue analogue (Eu-PB)film was prepared by means of electrodepositing and used as a working electrode.Given this,a series of Ru(bpy)32+-based ECL detection coupled with CE have been established for the determination of sinomenine,atropine sulfate,anisodine and/or anisodamine in plant extracts or in human urines,respectively.The present work would be helpful to the further developments of detection methods for some alkaloids and to the spreads of applications of CE-ECL technique.This paper consists of three parts.Part One AreviewChapter One Areview on ECL analysisThis chapter introduces the basic principles and the quantification foundation of ECL analysis.The common ECL systems and their analytical applications,as well as the applications of CMEs in ECL are also summarized.In addition,the vista of the newly developing techniques and further trends of ECL methods are reviewed,too.Chapter Two A review on CE techniqueThe basic principles,separation modes and detectors of CE are introduced in the chapter.The development of CE technique coupled with CL or ECL is reviewed as well.Chapter Three The development of analysis of alkaloidsAll kinds of methods including electrochemical methods,thin-layer chromatography(TLC),gas chromatography(GC),high-performance liquid chromatography(HPLC),and CE methods for the analysis of alkaloids in recent years are reviewed,and 55 references are cited.Part Two Preparation and performance of the Eu-PB modified platinum electrodeChapter Four Preparation and performance of the Eu-PB modified platinum electrodeA platinum electrode modified with Europinum(Ⅲ)-doped Prussian Blue analogue (Eu-PB)film was prepared successfully by means of electrodepositing.The stability, electrochemical characteristics of the prepared.electrode,and its effect on Ru(bpy)32+-based CE-ECL signal was studied by cyclic voltammograms and differential pulse voltammetries.The Ru(bpy)32+-based ECL mechanism at the modified electrode was preliminarily discussed as well.Part Three Applications of CE-ECL methods in the analysis of alkaloidsIn this part,some research reports were given.Based on the Ru(bpy)32+-based CE-ECL in the Eu-PB modified platinum electrode,a series of alkaloids including sinomenine,atropine,anisodine and anisodamine were separated and detected.The detailed works are as follows:Chapter Five Detection of sinomenine by CE-ECLA Ru(bpy)32+-based ECL coupled with CE has been established for the determination of sinomenine for the first time.Under the optimized conditions,the ECL intensity was in proportion to sinomenine concentration in the range from 0.01 to 1.0μg mL-1with a detection limit of 2.0 ng mL-1(3s).The relative standard derivations of migration time and ECL intensity were 0.93 and 1.11%,respectively. The levels of sinomenine in Sinomenium tablet and Sinomenium acutum were easily determined with recoveries between 98.6%and 102.7%.Chapter Six Detection of atropine sulfate by CE-ECLA Ru(bpy)32+-based ECL coupled with CE was developed for the determination of atropine sulfate at the Eu-PB modified platinum electrode.Under the optimized conditions,the ECL response peak area was in proportion to atropine sulfate concentration in the range 0.08-20μg·mL-1(r=0.9994)with a detection limit of 0.05μg mL-1.The relative standard derivations of migration time and peak area were 0.81 and 3.19%,respectively.The proposed method has been successfully applied to direct determination of atropine sulfate in injection and especially in human urines with the recoveries of 90.9-99.6%.Chapter Seven Separation and detection of tropane alkaloids in Anisodus tanguticus by CE-ECLA Ru(bpy)32+-based ECL coupled with CE has been established for the separation and detection of anisodine and anisodamine in Anisodus tanguticus for the first time. Under the optimized conditions,the ECL intensity was in proportion to anisodine and anisodamine concentrations in the range 5.0×10-6-1.0×10-3mol/L(r=0.9993)for anisodine and 1.0×10-6-1.0×10-3mol/L(r=0.9991)for anisodamine,with the detection limits of 1.2×10-7mol/L and 4.3×10-8mol/L,respectively.The proposed method has been successfully applied for the detection of two alkaloids in different parts of Anisodus tanguticus,and especially for the quantitative determination of anisodine in the plant seeds and roots with an average recovery of 102.9%and 97.4%, respectively.
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