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Testing of Polished Silver Solid Amalgam Composite Electrode for Voltammetric Determination of Environmental Pollutants
Dědík, Jan ; Vyskočil, Vlastimil (advisor) ; Nesměrák, Karel (referee)
The aim of this study was the finding of applicable conditions for the determination of selected model environmental pollutants, namely 5-nitrobenzimidazole and picric acid, using DC voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam composite electrode (p-AgSAE-CE) in the aqueous solution of Britton-Robinson (BR) and finding of the limit of quantification (LQ) for these substances. For 5-nitrobenzimidazole, the optimum conditions of voltammetric determination have been found in the medium of B-R buffer pH 5, but any calibration dependences were obtained. The reason was the deteriorating quality of 5-nitrobenzimidazole response even if the routine pretreatment of working electrode was maintained. This resulted in obtaining of irreproducible results upon the determination of 5-nitrobenzimidazole. For picric acid, the optimum conditions have been found for both DPV and DCV at p-AgSAE-CE in the medium of B-R buffer pH 2. The concentration dependences were measured in the range 1.10-6 - 1.10-4 mol.L-1 for DPV with the value of reached LQ 2,5.10-7 mol.L-1 and, for DCV, in the range 1.10-7 - 1.10-4 mol.L-1 with LQ calculated as 5,5.10-8 mol.L-1 . For comparison of newly developed voltammetric methods of picric acid determination, a UV-VIS spectrophotometric...
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Amperometric detection of aminoderivatives of biphenyl and naphthalene at screen printed carbon electrodes
Dědík, Jan ; Schwarzová, Karolina (advisor) ; Nesměrák, Karel (referee)
According to International Agency for Research on Cancer (IARC), some specific isomers of amino derivatives of polycyclic aromatic hydrocarbons (APAHs) are classified as carcinogenic to humans (Group 1). Several APAHs are employed in the manufacturing of widely-used azodyes, therefore, sensitive and selective analytical methods for their determinations are still needed. This study aims at the possibilities of detection of 2-aminobiphenyl (2-AB), 4-aminobiphenyl (4-AB), 1-aminonaphthalene (1-AN) and 2-aminonaphthalene (2-AN) using bare screen-printed carbon electrodes (SPCE). These were employed as working electrodes in amperometric detection flow cell for repeated use in liquid flow methods - reverse phase high performance liquid chromatography (RP-HPLC) and flow injection analysis. Sufficient stability and repeatability was obtained for mobile phases containing the maximum of 70% of acetonitrile. Limits of detection for 4-AB given by FIA in the aqueous solution of 0,01mol.l-1 phosphate buffer pH 3,0; or in the solution of acetonitrile and 0,01mol.l-1 phosphate buffer pH 3,0 (40:60) (V/V) were 1,0 mol·l-1 and 2,0 mol·l-1 , respectively. Using RP-HPLC in gradient mode, the mixture of aminobiphenyls and aminonaphthalenes was successfully separated below 11 minutes. Limits of detection for individual...
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Testing of Polished Silver Solid Amalgam Composite Electrode for Voltammetric Determination of Environmental Pollutants
Dědík, Jan ; Nesměrák, Karel (referee) ; Vyskočil, Vlastimil (advisor)
The aim of this study was the finding of applicable conditions for the determination of selected model environmental pollutants, namely 5-nitrobenzimidazole and picric acid, using DC voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam composite electrode (p-AgSAE-CE) in the aqueous solution of Britton-Robinson (BR) and finding of the limit of quantification (LQ) for these substances. For 5-nitrobenzimidazole, the optimum conditions of voltammetric determination have been found in the medium of B-R buffer pH 5, but any calibration dependences were obtained. The reason was the deteriorating quality of 5-nitrobenzimidazole response even if the routine pretreatment of working electrode was maintained. This resulted in obtaining of irreproducible results upon the determination of 5-nitrobenzimidazole. For picric acid, the optimum conditions have been found for both DPV and DCV at p-AgSAE-CE in the medium of B-R buffer pH 2. The concentration dependences were measured in the range 1.10-6 - 1.10-4 mol.L-1 for DPV with the value of reached LQ 2,5.10-7 mol.L-1 and, for DCV, in the range 1.10-7 - 1.10-4 mol.L-1 with LQ calculated as 5,5.10-8 mol.L-1 . For comparison of newly developed voltammetric methods of picric acid determination, a UV-VIS spectrophotometric...
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