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Polarographic Determination of Genotoxic 2-Amino-9-fluorenone
Hájková, Andrea ; Dejmková, Hana (referee) ; Vyskočil, Vlastimil (advisor)
of Bachaleor Thesis The aim to this work was to find the optimum conditions for polarographic determination of genotoxic 2-amino-9-fluorenone (2-AFN) that can negatively affect the living and working environment. Foremost, the stability of 2-AFN stock solution in methanol was monitored using UV-VIS spectrophotometry and an optimal ratio of buffered aqueous and methanolic phase was found out for following polarographic measurements at a classical mercury dropping electrode (DME). The dependence of polarographic behavior of 2-AFN (of concentration 1×10-4 mol dm-3 ) on pH of analyzed solution was measured using DC tast polarography (DCTP) and differential pulse polarography (DPP) in the pH range 1.9 - 12.8, in the medium of Britton-Robinson (BR) buffer - methanol (9:1). The mechanism of polarographic reduction of electrochemically reducible oxo group at 2-AFN has been proposed on the basis of thus observed behavior. The optimum medium of BR buffer pH 4.0 - methanol (9:1) has been chosen for both polarographic techniques. The concentration range from 1×10-6 to 1×10-4 mol dm-3 was measured using DCTP at DME and from 1×10-7 to 1×10-4 mol dm-3 using DPP at DME. Reached limits of quantification (LQs) were 5×10-7 mol dm-3 and 1×10-7 mol dm-3 for DCTP at DME and DPP at DME, respectively. For comparison, the...
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Polarographic Determination of the Herbicide Aclonifen
Murcková, Klára ; Vyskočil, Vlastimil (advisor) ; Dejmková, Hana (referee)
This thesis deals with the differential pulse polarographic determination of the herbicide aclonifen and with the TAST polarographic determination of the herbicide aclonifen. A dropping mercury electrode was used as the working electrode. UV/VIS spectrophotometric detection was used for comparison to electrochemical detection, the walenghts used were 308 nm and 388 nm. Optimal pH conditions were determined for determination using TP, DPP and UV/VIS spectrophotometry. The calibration dependences were measured using the found optimal conditions and limits of quantification, and limits of detection were determined. Limit of quantification for aclonifen were found to be 3,4·10-6 mol·L-1 using TP; 2,2·10-7 mol·L-1 using DPP and 4,6·10-6 mol·L-1 using UV/VIS spectrophotometry.
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Determination of carvacrol using HPLC with electrochemical detection
Mužíková, Jana ; Schwarzová, Karolina (referee) ; Dejmková, Hana (advisor)
This thesis deals with determination of a mixture of carvacrol with thymol and eugenol by HPLC with electrochemical detection. Carbon paste electrode was used as the working electrode. The separation was performed on Kromasil-C18, 250x4,6 mm column. For the comparison, UV spectrophotometric detection at 275 nm was used besides electrochemical detection. Optimal separation conditions were found: mobile phase consisting of acetonitrile and phosphate buffer in ratio 60:40, the optimal buffer pH was pH 4. As the optimum potential of working electrode during electrochemical detection, potential +1.1 V was found. Under the obtained optimal conditions, calibration dependences were measured. Limit of quantification for carvacrol was found to be 9,6·10-7 mol dm-3 using UV spectrophotometric detection and 4,0·10-8 mol dm-3 using electrochemical detection.
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Voltammetric Determination of 2-Methoxy-5-nitrophenol at Nontraditional Electrodes
Charvátová, Michala ; Dejmková, Hana (referee) ; Fischer, Jan (advisor)
Voltammetric determination of 2-methoxy-5-nitrophenol was studied using DC voltammetry (DCV) and differential pulse voltammetry (DPV) at a carbon film electrode (CFE) and a meniscus modified silver solid amalgam electrode (m-AgSAE). Conditions were found for its determination by DCV and DPV at CFE in Britton - Robinson buffer within concentration range 1.10-4 - 1.10-6 mol.l-1 . Using adsorptive stripping voltammetry (AdSV) m-AgSAE in Britton - Robinson buffer pH 2,0 compound this determined in the concentration range (2 - 10) .10-7 mol.l-1 with a limit of detection 3,6.10-7 mol.l-1 . Using a combination of DPV with solid phase extraction (SPE) for determination of 2-methoxy-5-nitrophenol in river water, limit of detection 6,6.10-8 mol.l-1 was abtained. Using cyclic voltammetry (CV) at m-AgSAE and at CFE mechanism of electrochemical reduction 2-methoxy-5-nitrophenol was proposed.
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