Academic literature on the topic 'Alkaloids – Separation'

The foci of this dissertation are on advanced liquid chromatography (LC) separation and mass spectrometry (MS) techniques for the analysis of small bioactive molecules. In addition to discussing general aspects of such techniques the results from analyses of polyphenols (PPs), alkaloids and amino acids published in five appended studies are presented and discussed. High efficiency and well understood principles make LC the method of choice for separating analytes in many kinds of scientific investigations. Moreover, when LC is coupled to an MS instrument, analytes are separated in two stages: firstly they are separated and pre-concentrated in narrow bands using LC and then separated according to their mass-to-charge (m/z) ratios in the MS instrument. Some MS instruments can provide highly accurate molecular weight measurements and mass resolution allowing identification of unknown compounds based purely on MS data, thus making prior separation unnecessary. However, prior separation is essential for analyzing substances in most complex matrices – especially useful is the ultra-high performance LC (UHPLC). The advantages of using UHPLC rather than HPLC for the analysis of PPs in tea and wine were evaluated in one of the studies this thesis is based upon. The phenolic composition of red wine was also examined, using a novel LDI technique, following solid phase extraction (SPE). A class of small aromatic molecules (medicinally important alkaloids) also proved to be amenable to straightforward analysis, by thin layer chromatography (TLC) work-up followed by LDI-MS. Finally, a LC-MS method for monitoring neurotoxins (β-N-methyl-amino-L-alanine and 2,3-diaminobutyric acid) in complex biological matrices was developed and applied. Overall, the studies show that careful attention to the physicochemical properties of analytes can provide insights that can greatly facilitate the development of alternative methods to analyze them, e.g. by LDI.<br><p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: In press. Paper 5: Manuscript.</p>

碩士<br>國立臺灣大學<br>藥學系<br>85<br>This thesis is composed of two parts:Part I : 1. Analysis of Bisbenzylisoquinoline Alkaloids by High Performance Liquid Chromatography2. Capillary Electrophoretic Separation of Bisbenzylisoquinoline AlkaloidsPart II : Analysis of Fluoroquinolone Antibacterials by Capillary ElectrophoresisPart I1. Analysis of Bisbenzylisoquinoline Alkaloids by High Performance Liquid ChromatographyA well-resolved high- performance liquid chromatographic method has been developed for the analysis of nine type VI and type VIII bisbenzylisoquinoline alkaloids ( aromoline, obamegine, berbamine, homoaromoline, colorflammine, thalrugosine, norobaberine, tetrandrine and isotetrandrine. The method used the reversed-phase ion-pair chromatography aided by the photodiode array UV detection. The mobile phase was composed of 27 % volume of acetonitrile and 73 % volume of 0.05 M dihydogen phosphate buffer (pH 3.0) to which 0.1% diethylamine (v/v) and 2 mM sodium heptanesulfonate were added. The method was applied to the analysis of these alkaloids in the stem woods of a Lauraceous plant Dehaasia triandra Merr. Five such alkaloids were identified and their contents were determined. This method should be applicable to the other Lauraceous plants and the various plants containing type VI and type VIII bisbenzylisoquinoline alkaloids.2. Capillary Electrophoretic Separation of Bisbenzylisoquinoline AlkaloidsIn this study, the use of the overlapping resolution mapping scheme to achieve an optimum capillary electrophoretic separation of eight bisbenzylisoquinoline alkaloids, aromoline, obamegine, berbamine, homoaromoline, colorflammine, thalrugosine, tetrandrine and isotetrandrine was investigated. Three critical parameters of electrophoretic media surfactant (sodium cholate), organic modifier (acetonitrile) and pH were chosen to carry out the process. Eight bisbenzylisoquinoline alkaloids were baseline-separated within 20 minutes using the predicted conditions of an optimum separation: buffer containing 132 mM sodium cholate, 25.8% acetonitrile (v/v) and pH 7.58.Part IIAnalysis of Fluoroquinolone Antibacterials by Capillary ElectrophoresisTo meet the requirement of quantitative analysis, this work re-investigated the parameters which were relevant to the separation of the seven fluoroquinolone antibacterials, sparfloxacin, lomefloxacin, norfloxacin, ciprofloxacin, enoxacin, ofloxacin and pefloxacin, based on the method developed previously in this laboratory. With the optimum conditions obtained as follows: electrophoretic media ( 65 mM sodium borate, 35 mM sodium dihydrogen phosphate, 60 mM sodium cholate, pH 7.3 / ACN (72 : 28, v/v); fused silica capillary ( 50 (m I.D., total length 67 cm, effective length 52 cm; injection pressure ( 60 mbar, injection time ( 3 sec; voltage ( 27 kV; detection wavelength ( 275 nm and temperature ( 25℃, the fluoroquinolones were well separated within nine miniutes. After validation with the reproducibility, linearity and accuracy criteria the method was used for the assay of the commercial formulation products. The assay results were within 95~105 % of their labeled claims. The method should be applicable to the analysis of these and other similar formulation products containing these drugs.

碩士<br>國立臺灣大學<br>藥學研究所<br>84<br>The aim of the part I of the thesis was to develop a rapid capi- llary electrophoretic method for the analysis of aporphine alka- loids from lauroaceous plants. Micellar electrokinetic chromato- graphic mode of capillary electrophoresis was used to separate nine aporphine alkaloids: lindcarpine, N-methyllindcarpine, boldine, norpredicentrine, isocorydine, laurotetanine, N-methyl- laurotetanine and isoboldine which had been isolated from some lauroaceous plants. Several critical factors affecting the sepa- rations: electrolyte concentration, surfactant concentration, ion-pair reagent, organic solvent and the buffer pH were invest- igated. Under the following conditions: 20 mM sodium borate, 30 mM sodium dodecylsulfate, 5 mM sodium heptanesulfnate, 5% aceto- nitrile (v/v) and pH 9.3, the nine alkaloids were well separated within 9 min. This condition was then used to determine in the leaves of Neolitsea sericea var. aurata. The results correspond- ed with those obtained from HPLC. THe purpose of this part II of the thesis was to develop a rapid capillary electrophoretic method for the separation of fourteen quinolone antibacterials: cinoxacin, ciprofloxacin, enoxacin, flumequine, lomefloxacin, nalidixic acid, norfloxacin, ofloxacin, oxolinic acid, pefloxac- in, pipemidic acid, piromidic acid, rosoxacin and sparfloxacin. By appliaction of the overlapping resolution mapping scheme, an optimum separation of the quinolone antibacterials was achieved. The concentrations of three major parameters of electrophoretic media - the surfactant (sodium cholate),the ion-pairing reagent (sodium heptanesulfonate), and organic modifier (acetonitrile) were chosen to carry out the process. The quinolone compounds were baseline-separated within 8 minutes using the predicted co- nditions of an optimum separation: buffer containing 39 mM sodi- m cholate, 8 mM sodium heptanesulfonate, and 28% acetonitrile.