A new method for benzocaine determination employing FIA and HPLC with electrochemical detection o... more A new method for benzocaine determination employing FIA and HPLC with electrochemical detection on a carbon paste electrode was developed. The optimum conditions for the determination were found. Carrier solution for FIA consisted of B–R buffer pH 4 (80 % methanol, v/v) and used flow rate was 1.0 mL min−1. Mobile phase for HPLC consisted of B–R buffer pH 4 (75 % methanol, v/v) with flow rate 0.4 mL min−1. Working potential of +1.2 V was employed. Practical applicability of the methods was tested on the determination of benzocaine in selected pharmaceuticals. The results were in agreement with results obtained using spectrophotometric detection and with one exception also with the content declared by the manufacturer.
The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixe... more The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixed methanol‐water solutions by differential pulse voltammetry (DPV) at boron doped diamond thin‐film electrode (BDDE). Optimum conditions have been found for determination of 3‐nitrofluoranthene in the concentration range of 2×10−8–1×10−6 mol L−1, and for determination 3‐aminofluorathnene in the concentration range of 2×10−7–1×10−5 mol L−1, respectively. Limits of determination were 3×10−8 mol L−1 (3‐nitrofluoranthene) and 2×10−7 mol L−1 (3‐aminofluoranthene).
Abstract High‐performance liquid chromatography with fluorescence detection (HPLC‐FD) was used fo... more Abstract High‐performance liquid chromatography with fluorescence detection (HPLC‐FD) was used for the determination of 1‐nitropyrene, 2‐nitrofluorene, and 6‐nitrochrysene after their reduction to amino derivatives. As a reducing agent, titanium(III) complexed with citrate in a hydrochloric acid medium was used. Conditions for 1‐nitropyrene, 2‐nitrofluorene, and 6‐nitrochrysene reduction, and for separation of corresponding amino derivatives were found. The limit of detection was 68 pg for 2‐nitrofluorene, 82 pg for 2‐nitropyrene, and 629 pg for 6‐nitrochrysene. The applicability of this method for the determination of 1‐nitropyrene in water samples was verified.
Collection of Czechoslovak Chemical Communications, 1989
The polarographic reduction of 4-haloderivatives of N,N-dimethyl-4-aminoazobenzene has been studi... more The polarographic reduction of 4-haloderivatives of N,N-dimethyl-4-aminoazobenzene has been studied in mixed water-methanol medium, a mechanism has been proposed and optimal conditions have been found for determination of these substances by TAST polarography with a determination limit of about 1.10-6 mol l-1, by differential pulse polarography with a determination limit of about 1.10-7 mol l-1 and linear scan voltammetry with a determination limit of about 5.10-8 mol l-1. In the latter technique, the determined substance was accumulated by adsorption on the surface of a hanging mercury drop electrode to decrease the determination limit below 1.10-8 mol l-1.
Collection of Czechoslovak Chemical Communications, 2006
The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP)... more The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV), both at a hanging mercury drop electrode. Optimum conditions have been found for its determination by the given methods in the concentration ranges of 1 × 10-6-1 × 10-4 mol l-1 (DCTP), 1 × 10-7-1 × 10-4 mol l-1 (DPP), 1 × 10-8-1 × 10-6 mol l-1 (DPV) and 1 × 10-9-1 × 10-7 mol l-1 (AdSV), respectively. Practical applicability of these techniques was demonstrated on the determination of 3-nitrofluoranthene in drinking and river water after its preliminary separation and preconcentration using liquid-liquid and solid phase extraction with the limits of determination 4 × 10-10 mol l-1 (drinking water) and 2 × 10-9 mol l-1 (river water).
The following optimised conditions for the separation of naphthalene, naphthalen-1-amine, naphtha... more The following optimised conditions for the separation of naphthalene, naphthalen-1-amine, naphthalen-2-amine, 1- and 2-naphthols, and 1- and 2-nitronaphthalenes were found using a combination of the prediction of chromatographic behaviour of the tested substances with ChromSwordr (Merck) optimisation software and experimental verification: LiChrospherr column, 24-min linear gradient, acetonitrile (40 - 70 %) - phosphate buffer, pH 2.3 (60 - 30 %), flow rate 0.5 ml/min, UV detection at 285 nm.
The reduction of mutagenic bisazodye trypane blue has been studied at a mercury electrode, a mech... more The reduction of mutagenic bisazodye trypane blue has been studied at a mercury electrode, a mechanism has been proposed and optimal conditions found for its analytical application. The use of a dropping mercury electrode with a renewable surface yielded a detection limit of 8 . 10-7 mol l-1 for TAST polarography, and 8 . 10-8 mol l-1 for differential pulse polarography; the use of a hanging mercury drop electrode with an unrenewed surface during the measurement yielded detection limit of 6 . 10-8 mol l-1 for fast scan differential pulse voltammetry and 4 . 10-8 mol l-1 for linear scan voltammetry. Preliminary adsorptive accumulation of the determined substance on the surface of the hanging mercury drop electrode led to a decrease in the detection limit to 5 . 10-9 mol l-1 for linear scan voltammetry.
HPLC systems with electrochemical, UV spectrophotometric, and fluorescent detectors were used to ... more HPLC systems with electrochemical, UV spectrophotometric, and fluorescent detectors were used to determine genotoxic derivatives of biphenyl – 4-aminobiphenyl (4-ABP) and 4-nitrobiphenyl (4-NBP). As 4-NBP cannot be determined by electrochemical and fluorescent detector directly, reduction of 4-NBP to 4-ABP (making use of a titanium(III)-based reducing agent) was investigated and optimized. UV detection was found to be the least sensitive and fluorescent detection the most sensitive one. Limits of detection (LDs) for 4-ABP in the presence of a reducing agent were 6.0 × 10-6 mol L-1 , 2.0 × 10-6 mol L-1 , and 8.0 × 10-8 mol L-1 for UV, electrochemical, and fluorescent detection, respectively. For the determination of 4-NBP after its reduction to 4-ABP, the obtained LDs were 8.0 × 10-6 mol L-1 (UV), 4.0 × 10-6 mol L-1 (electrochemical), and 2.0 × 10-7 mol L-1 (fluorescent detection). Moreover, it was also possible to determine 4-NBP directly using HPLC with UV detection, where the LD w...
An amperometric detector with a diamond-film working electrode was tested for the determination o... more An amperometric detector with a diamond-film working electrode was tested for the determination of 1?aminonaphthalene and 2?aminobiphenyl by liquid chromatography. The noise, background current, signal stability, linearity of calibration curve and detection limits were compared with the parameters obtained using classic glassy carbon electrode. The signal of analytes was reproducible and stable at least for 8 h for both electrode materials. Calibration curves were linear in the whole range (10-7 - 10-4 mol/L) and the sensitivity was higher for the glassy carbon electrode. Both the background current and noise were substantially lower on the diamond-film electrode. As a result, the detection limits of analytes (1.10?7 mol/L for both analytes) were 5-7 times lower for the diamond-film electrode.
A new method for benzocaine determination employing FIA and HPLC with electrochemical detection o... more A new method for benzocaine determination employing FIA and HPLC with electrochemical detection on a carbon paste electrode was developed. The optimum conditions for the determination were found. Carrier solution for FIA consisted of B–R buffer pH 4 (80 % methanol, v/v) and used flow rate was 1.0 mL min−1. Mobile phase for HPLC consisted of B–R buffer pH 4 (75 % methanol, v/v) with flow rate 0.4 mL min−1. Working potential of +1.2 V was employed. Practical applicability of the methods was tested on the determination of benzocaine in selected pharmaceuticals. The results were in agreement with results obtained using spectrophotometric detection and with one exception also with the content declared by the manufacturer.
The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixe... more The voltammetric behavior of 3‐nitrofluoranthene and 3‐aminofluoranthene was investigated in mixed methanol‐water solutions by differential pulse voltammetry (DPV) at boron doped diamond thin‐film electrode (BDDE). Optimum conditions have been found for determination of 3‐nitrofluoranthene in the concentration range of 2×10−8–1×10−6 mol L−1, and for determination 3‐aminofluorathnene in the concentration range of 2×10−7–1×10−5 mol L−1, respectively. Limits of determination were 3×10−8 mol L−1 (3‐nitrofluoranthene) and 2×10−7 mol L−1 (3‐aminofluoranthene).
Abstract High‐performance liquid chromatography with fluorescence detection (HPLC‐FD) was used fo... more Abstract High‐performance liquid chromatography with fluorescence detection (HPLC‐FD) was used for the determination of 1‐nitropyrene, 2‐nitrofluorene, and 6‐nitrochrysene after their reduction to amino derivatives. As a reducing agent, titanium(III) complexed with citrate in a hydrochloric acid medium was used. Conditions for 1‐nitropyrene, 2‐nitrofluorene, and 6‐nitrochrysene reduction, and for separation of corresponding amino derivatives were found. The limit of detection was 68 pg for 2‐nitrofluorene, 82 pg for 2‐nitropyrene, and 629 pg for 6‐nitrochrysene. The applicability of this method for the determination of 1‐nitropyrene in water samples was verified.
Collection of Czechoslovak Chemical Communications, 1989
The polarographic reduction of 4-haloderivatives of N,N-dimethyl-4-aminoazobenzene has been studi... more The polarographic reduction of 4-haloderivatives of N,N-dimethyl-4-aminoazobenzene has been studied in mixed water-methanol medium, a mechanism has been proposed and optimal conditions have been found for determination of these substances by TAST polarography with a determination limit of about 1.10-6 mol l-1, by differential pulse polarography with a determination limit of about 1.10-7 mol l-1 and linear scan voltammetry with a determination limit of about 5.10-8 mol l-1. In the latter technique, the determined substance was accumulated by adsorption on the surface of a hanging mercury drop electrode to decrease the determination limit below 1.10-8 mol l-1.
Collection of Czechoslovak Chemical Communications, 2006
The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP)... more The polarographic behavior of 3-nitrofluoranthene was investigated by DC tast polarography (DCTP) and differential pulse polarography (DPP), both at a dropping mercury electrode, differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV), both at a hanging mercury drop electrode. Optimum conditions have been found for its determination by the given methods in the concentration ranges of 1 × 10-6-1 × 10-4 mol l-1 (DCTP), 1 × 10-7-1 × 10-4 mol l-1 (DPP), 1 × 10-8-1 × 10-6 mol l-1 (DPV) and 1 × 10-9-1 × 10-7 mol l-1 (AdSV), respectively. Practical applicability of these techniques was demonstrated on the determination of 3-nitrofluoranthene in drinking and river water after its preliminary separation and preconcentration using liquid-liquid and solid phase extraction with the limits of determination 4 × 10-10 mol l-1 (drinking water) and 2 × 10-9 mol l-1 (river water).
The following optimised conditions for the separation of naphthalene, naphthalen-1-amine, naphtha... more The following optimised conditions for the separation of naphthalene, naphthalen-1-amine, naphthalen-2-amine, 1- and 2-naphthols, and 1- and 2-nitronaphthalenes were found using a combination of the prediction of chromatographic behaviour of the tested substances with ChromSwordr (Merck) optimisation software and experimental verification: LiChrospherr column, 24-min linear gradient, acetonitrile (40 - 70 %) - phosphate buffer, pH 2.3 (60 - 30 %), flow rate 0.5 ml/min, UV detection at 285 nm.
The reduction of mutagenic bisazodye trypane blue has been studied at a mercury electrode, a mech... more The reduction of mutagenic bisazodye trypane blue has been studied at a mercury electrode, a mechanism has been proposed and optimal conditions found for its analytical application. The use of a dropping mercury electrode with a renewable surface yielded a detection limit of 8 . 10-7 mol l-1 for TAST polarography, and 8 . 10-8 mol l-1 for differential pulse polarography; the use of a hanging mercury drop electrode with an unrenewed surface during the measurement yielded detection limit of 6 . 10-8 mol l-1 for fast scan differential pulse voltammetry and 4 . 10-8 mol l-1 for linear scan voltammetry. Preliminary adsorptive accumulation of the determined substance on the surface of the hanging mercury drop electrode led to a decrease in the detection limit to 5 . 10-9 mol l-1 for linear scan voltammetry.
HPLC systems with electrochemical, UV spectrophotometric, and fluorescent detectors were used to ... more HPLC systems with electrochemical, UV spectrophotometric, and fluorescent detectors were used to determine genotoxic derivatives of biphenyl – 4-aminobiphenyl (4-ABP) and 4-nitrobiphenyl (4-NBP). As 4-NBP cannot be determined by electrochemical and fluorescent detector directly, reduction of 4-NBP to 4-ABP (making use of a titanium(III)-based reducing agent) was investigated and optimized. UV detection was found to be the least sensitive and fluorescent detection the most sensitive one. Limits of detection (LDs) for 4-ABP in the presence of a reducing agent were 6.0 × 10-6 mol L-1 , 2.0 × 10-6 mol L-1 , and 8.0 × 10-8 mol L-1 for UV, electrochemical, and fluorescent detection, respectively. For the determination of 4-NBP after its reduction to 4-ABP, the obtained LDs were 8.0 × 10-6 mol L-1 (UV), 4.0 × 10-6 mol L-1 (electrochemical), and 2.0 × 10-7 mol L-1 (fluorescent detection). Moreover, it was also possible to determine 4-NBP directly using HPLC with UV detection, where the LD w...
An amperometric detector with a diamond-film working electrode was tested for the determination o... more An amperometric detector with a diamond-film working electrode was tested for the determination of 1?aminonaphthalene and 2?aminobiphenyl by liquid chromatography. The noise, background current, signal stability, linearity of calibration curve and detection limits were compared with the parameters obtained using classic glassy carbon electrode. The signal of analytes was reproducible and stable at least for 8 h for both electrode materials. Calibration curves were linear in the whole range (10-7 - 10-4 mol/L) and the sensitivity was higher for the glassy carbon electrode. Both the background current and noise were substantially lower on the diamond-film electrode. As a result, the detection limits of analytes (1.10?7 mol/L for both analytes) were 5-7 times lower for the diamond-film electrode.
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