Beata Krasnodębska-Ostręga - Academia.edu (original) (raw)

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Papers by Beata Krasnodębska-Ostręga

Analytical Methods

Reduction of Tl(iii) and oxidation of As(iii), which are unstable speciation forms, start just af... more Reduction of Tl(iii) and oxidation of As(iii), which are unstable speciation forms, start just after sampling as a result of disturbed chemical equilibrium.

Talanta, 2017

The developed by us electrochemical device for vitamin B (VB; riboflavin) determination, without ... more The developed by us electrochemical device for vitamin B (VB; riboflavin) determination, without preconcentration step, in real products exhibits high sensitivity, selectivity, stability and low detection limit compared to those described in the literature. The determination procedure was based on the monitoring of the reduction current signal of VB bound with dsDNA anchored to the electrode surface through intermediary - carboxyphenyl layer. The application of such intermediary layer formed during electroreduction of appropriate diazonium salt at CV peak potential guarantees high efficiency of hybridization process and thus fully available places for VB interaction. Moreover, such intermediary layer provides good electrical contact, what is very important in the case of electrochemical sensors. The analytical range of work of the proposed VB sensor was between 0.08-1µM (30-377μgL) of riboflavin concentration. The obtained detection (LOD) and quantification limits (LOQ) were 24±2 and 55±5μgL, respectively. The proposed VB detection method was used for determination of riboflavin content in commercially available dietary supplements and yolk of hen egg samples. The accuracy of the obtained data was proved using comparison with an independent method (HPLC FLD).

Electrochimica Acta, 2021

Chemosphere, 2018

The applicability of photolysis in the speciation analysis of arsenic is investigated. The use of... more The applicability of photolysis in the speciation analysis of arsenic is investigated. The use of nano scale semiconductors (FeO/WO/FeO at pH 6) as an active film during solar light irradiation of a water sample, containing some surfactants (SDS), results in the simplification of the organic matter and gives no speciation change in the arsenic. The reproducibility of active layer is shown to be high and the surface roughness of each photoactive sample and photocurrent do not differ by more than 6 and less than 8%, respectively. The procedure of sample pretreatment caused a minimum (8-10%) amount of speciation change, whilst the irradiation is no longer that 2 h. The study indicates that "soft decomposition" can be performed for as long as 4 h, and still give photostable arsenates (III) and methylarsenate species. However, the saturation of the water sample with Ar is required (to reduce the oxygen content) for the longer the decomposition time being applied.

Talanta, 2017

International Journal of Environmental Analytical Chemistry, 2015

Phytochelatins (PCs) play an important role in the detoxification and homeostasis processes in pl... more Phytochelatins (PCs) play an important role in the detoxification and homeostasis processes in plants, since xenobiotics complexed by sulfhydryl groups are less toxic than the free ions. This paper describes studies related to PCs synthesis in Sinapis alba L. exposed to As and Tl salts, and in particular to the identification of the PC complexes that are formed in white mustard tissues. To reach the goal, two analytical methods were applied – high-performance liquid chromatography with fluorescent detection analysis after derivatisation of thiol compounds and high-performance liquid chromatography with electrospray ionization mass spectrometry (HPLC ESI MS). The study confirmed the synthesis of PCs in all plant organs under the influence of As salt. Moreover two As-PC complexes were identified: As-PC3 and As-PC4. While in the case of Tl – although that element strongly influenced the growth of Sinapis alba L. and to a great extent was transported to above-ground organs – no PC complexes or free PCs were found in plants exposed to Tl salt. Although both elements exist in mustard plant tissues at their trivalent oxidation state, showing high affinity to thiol groups, a defence mechanism associated with the synthesis of PC occurred only in case of arsenic.

Fresenius' Journal of Analytical Chemistry, 1998

Talanta, 2014

Monitoring of PGEs content in the natural samples is a crucial point in the environment science s... more Monitoring of PGEs content in the natural samples is a crucial point in the environment science since catalytic car converters have been introduced. In the presented paper application of a very sensitive voltammetric method for determination of traces of Pt and Rh in the environmental samples contaminated by automobile exhausts is discussed. Voltammetric measurements were carried out in the supporting electrolyte containing formaldehyde and semicarbazide. PGEs were separated from the digested solutions of soils or quartz samples, collected from monitoring plots-by applying an ion-exchange resin Cellex-T. Pt was very effectively separated from the matrix approaching nearly 100% recovery after its elution by hydrochloric acid. Moreover the conditions of soil and quartz samples digestion were discussed. To validate the obtained result an independent analytical method-ICP MS was applied and analysis of certified reference material road dust 723-was completed.

Talanta, 2013

The interactions of Tl(I), a well known toxic species, with selected oligonucleotides were examin... more The interactions of Tl(I), a well known toxic species, with selected oligonucleotides were examined. The oligonucleotide sequences selected for the investigation were taken from gene hOGG1 responsible for repairing of DNA damage. Cyclic voltammetry was particularly useful, since nitrogen N-7 in guanine can be electrooxidized while its binding with Tl(I) leads to the loss of electroactivity. So, this selected interaction could be quantitatively used in drawing Scatchard&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s plot and calculating the binding constants and the number of active sites in guanine molecules occupied by one metal ion. Further, we have shown that the presence of Tl(I) leads to a decrease in activity of doxorubicin (DOX), a popular anticancer drug, vs. DNA. The obtained circular dichroism (CD) spectra and the measurements with an electrochemical quartz crystal microbalance (EQCM) led to a conclusion that in the presence of monovalent thallium cations the DNA double helix was neither damaged/oxidized nor its conformation changed substantially.