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Voltammetric Determination of Selected Psychopharmaceuticals Using Carbon Electrodes
Matouš, Petr ; Vyskočil, Vlastimil (advisor) ; Fischer, Jan (referee)
Differential pulse voltammetry (DPV) was used for developing a method for the determination of phenothiazine derivatives, namely chlorpromazine (CHP) and levomepromazine (LMP), using a glassy carbon electrode (GCE) and a graphite electrode, both with a 2 mm disc diameter. Comparison of quantification limits (LQ) for both substances on both electrodes was performed. After optimizing and processing the results, the optimal conditions for measuring calibrations were as follows: Britton- Robinson (BR) buffer at pH 4.0. Calibration dependences were measured inthe concentration range from 1·10-7 to 1·10-4 mol·dm-3 . There was no need for electrochemical electrode regeneration or matrix pretreatment. The results showed higher measurement sensitivity for CHP, and the graphite electrode also showed higher sensitivity. Although there were measured lower concentrations with the graphite electrode in comparison to the GCE, because of the low repeatability of the measurements in the lower concentration range 1-10·10-7 mol·dm-3 , the LQ is comparable to the results reached on the GCE. Besides to the BR buffer, measurements in other matrices (drinking water and river water) were also made. The following LQ values were achieved: 1.0·10-6 mol·dm-3 (in BR buffer), 1.1·10-6 -1.4·10-6 mol·dm-3 (in drinking water) and...
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Cyclic Voltammetry as a Detection Technique in High Performance Liquid Chromatography
Burešová, Helena ; Nesměrák, Karel (advisor) ; Schwarzová, Karolina (referee)
The aim of the thesis was to study the possibility of employment of cyclic voltammetry as a detection technique in liquid chromatography. The phenothiazine derivatives (chlorpromazine hydrochloride, diethazine hydrochloride, and thioridazine hydrochloride) were used as model compounds. Firstly, the comparison of two potential detectors (tubular detector and bulk "wall-jet" detector) was accomplished. Only bulk "wal-jet" detector satisfied. Next, the conditions for the separation and detection of studied phenothiazines on RP-select B LiChrospher® 60 (250×4 mm) column with cyclic voltammetry as the detection techniques were optimized. The best separation is achieved in mobile phase consisted from the solution of 0.1 mol dm-3 sodium perchlorate in acetonitrile-water (80:20) mixture. The effect of flow rate of mobile phase and scan rate of polarization of the electrode on the symmetry of chromatographic peak was also followed, and optimal values of 0.5 ml min-1 for flow rate, and of 0.5 V s-1 for scan rate, were found. Under optimized conditions the calibration dependences of studied phenothiazines were measured in the range from 5×10-5 to 1×10-3 mol dm-3 for chlorpromazine, and in the range from 8×10-5 to 1×10-3 mol dm-3 for diethazine and thioridazine. The developed method was applied to...
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