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Mila Pravda

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Papers by Mila Pravda

A sensor has been developed that selectively catalyses the oxidation of l-ascorbic acid at low po... more A sensor has been developed that selectively catalyses the oxidation of l-ascorbic acid at low potentials (+100 mV). The low applied potential minimises the effects of many common electrochemical interferents. The interferents tested are those commonly found in juices and pharmaceutical preparations, including 4-acetamidophenol (paracetamol), uric acid and citric acid. Polyaniline was grown on both glassy carbon and screen-printed electrodes, and the analytical behaviour of both sensor types investigated. The linear ranges of the batch mode sensors were determined to be between 0.4 M and 2 mM, with a limit of detection of 0.4 M, while in flow injection format the linear range extended from 5 M to 0.1 mM with a limit of detection of 2.45 M.

A biosensor for on-line monitoring of glucose in brain dialysates was developed. The biosensor wa... more A biosensor for on-line monitoring of glucose in brain dialysates was developed. The biosensor was generated in the cross-¯ow amperometric cell by potentiostatic electropolymerization of phenol (50 mM) in the presence of glucose oxidase (935 U/mL) at 600 mV (vs. Ag/AgCl) at a ¯ow-rate of 5 mLamin at the Pt electrode. The polyphenol ®lm ensured low interferences of ascorbate. The on-line setup was mathematically described and the model was used to calculate the extracellular concentration of glucose in the striatum of an anes-thetized rat. The concentration of glucose was found to be 1.4 + 0.5 mM and 0.9 + 0.2 mM in two independent experiments.

Differential-pulse anodic-stripping voltammetry with the use of a pen-type hanging mercury-drop e... more Differential-pulse anodic-stripping voltammetry with the use of a pen-type hanging mercury-drop electrode was investigated for thc determination of indium as dopant in milligram samples of thermoelectric bismuth-telluride material. After dissolving a milligram sample in dilute HN03, telluric acid present in a great excess was oxidized by H202 in ammoniacal medium to the less interfering Te("". I n contrast with the supporting electrolytes containing sulfuric, nitric, perchloric, and hydrochloric acid, respectively, a higher sensitivity was achieved with a citrate buffer (of pH 2.6-2.9). The calibration plot was linear up to a concentration of about 2 p g In("') per 1 inL of the measured solution; the corresponing detection limit was 5.6 ng/mL (49 nmol/L). A standard bismuth telluride material containing 2.94% w./w. In was used to compare the results o f the method with applications of flame atomic absorption spectrometry, extraction spectrophotometry and scanning energy dispersive X-ray analysis.

Sensors and Actuators B: Chemical, 2016

A novel electrochemical sensor consisting of l-cysteine self-assembled monolayers over gold nanop... more A novel electrochemical sensor consisting of l-cysteine self-assembled monolayers over gold nanoparticles/multi-walled carbon nanotubes modified glassy carbon electrode (L-Cys/AuNPs/MWCNTs/GCE) was fabricated and applied for the determination of norepinephrine (NE) in the presence of sodium dodecyl sulfate (SDS) for the first time. Electroanalytical measurements including cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used. The optimum buffer of pH 5.0 contained 30 M SDS, the NE oxidation peak current enhanced linearly with concentration ranging from 0.2 to 100 M (R2 of 0.9998) with a detection limit of 0.03 M. In the presence of SDS, the modified L-Cys/AuNPs/MWCNTs/GCE electrode showed high selectivity for the detection of NE in the presence of ascorbic acid and uric acid. High recoveries in the range of 80.7–100.2% were obtained in spiked human serum samples. Our modified electrode displayed a high reproducibility, sensitivity and long term stability.

International Journal of Environmental Analytical Chemistry, 2003

Analytical Letters, 2003

Abstract The current work describes the raising of polyclonal antibodies (pAbs) against domoic ac... more Abstract The current work describes the raising of polyclonal antibodies (pAbs) against domoic acid (DA), an algal toxin produced by the diatom Pseudonitzschia pungens. They were screened for sensitivity and selectivity using a competitive enzyme-linked ...