- MeSH
- Chemistry Techniques, Analytical * methods utilization MeSH
- Diclofenac * analysis MeSH
- Technology, Pharmaceutical MeSH
- Indicators and Reagents MeSH
- Humans MeSH
- Analytic Sample Preparation Methods MeSH
- Analgesics, Non-Narcotic MeSH
- Sewage * MeSH
- Reference Standards MeSH
- Spectrophotometry, Ultraviolet * methods instrumentation utilization MeSH
- Check Tag
- Humans MeSH
Hydroxybenzoic acids are effective radical scavengers. Gallic, 2,4-di-hydroxybenzoic, 3,5-dihydroxybenzoic, and caffeic acids gave the best results.
- MeSH
- Antioxidants * MeSH
- Hydroxybenzoates * MeSH
- Peroxynitrous Acid * MeSH
- Humans MeSH
- Neoplasms prevention & control MeSH
- Oxidative Stress MeSH
- Pathologic Processes prevention & control MeSH
- Spectrophotometry, Ultraviolet * MeSH
- Free Radicals * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
IX, 244 s. : il.
The effects of iron-chelating agents on miscellaneous pathologies are currently largely tested. Due to various indications, different properties for chelators are required. A stoichiometry of the complex in relation to pH is one of the crucial factors. Moreover, the published data on the stoichiometry, especially concerning flavonoids, are equivocal. In this study, a new complementary approach was employed for the determination of stoichiometry in 10 iron-chelating agents, including clinically used drugs, by UV-Vis spectrophotometry at relevant pH conditions and compared with the standard Job's method. This study showed that the simple approach based on absorbance at the wavelength of complex absorption maximum was sufficient when the difference between absorption maximum of substance and complex was high. However, in majority of substances this difference was much lower (9-73 nm). The novel complementary approach was able to determine the stoichiometry in all tested cases. The major benefit of this method compared to the standard Job's approach seems to be its capability to reveal a reaction stoichiometry in chelators with moderate affinity to iron. In conclusion, using this complementary method may explain several previous contradictory data and lead to a better understanding of the underlying mechanisms of chelator's action.
- Publication type
- Meeting Abstract MeSH
Acetylcholinesterase reactivators (oximes) are compounds used for antidotal treatment in case of organophosphorus poisoning. The dissociation constants (pK(a1)) of ten standard or promising acetylcholinesterase reactivators were determined by ultraviolet absorption spectrometry. Two methods of spectra measurement (UV-vis spectrometry, FIA/UV-vis) were applied and compared. The soft and hard models for calculation of pK(a1) values were performed. The pK(a1) values were recommended in the range 7.00-8.35, where at least 10% of oximate anion is available for organophosphate reactivation. All tested oximes were found to have pK(a1) in this range. The FIA/UV-vis method provided rapid sample throughput, low sample consumption, high sensitivity and precision compared to standard UV-vis method. The hard calculation model was proposed as more accurate for pK(a1) calculation.
- MeSH
- Acetylcholinesterase analysis chemistry MeSH
- Chemistry, Pharmaceutical methods standards MeSH
- Oximes analysis chemistry MeSH
- Cholinesterase Reactivators analysis chemistry MeSH
- Spectrophotometry, Ultraviolet methods standards MeSH
- Structure-Activity Relationship MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Validation Study MeSH
In this work, we describe the introduction of a post-column solid-state reactor in the HPLC system used for the analyses of amino acids. The reactor used was filled with copper(II) oxide. Passage of the analytes through the reactor leads to the formation of Cu(II) complexes. Unlike free amino acids, the Cu-complexes show significant absorbance in the UV region and accordingly sensitivity of UV-VIS detection is increased by two to three orders of magnitude. As a result of this improvement in sensitivity, we have obtained LOD values in micromolar range and good linearity over the studied concentration range (5.0×10(-5) to 2.0×10(-3) mol/L). The method exhibits advantages typical of solid-state reactors, such as negligible loss of efficiency due to the derivatization, simplicity of realization and a long-term durability. The presented system brings an easy and versatile solution for UV-VIS detection of coordinating compounds, which do not normally absorb well in the UV-VIS region.
