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Speciation analysis of toxicologocally important forms of arsenic: development and comparison of hydride generation based methods with ICP-MS detection
Trojánková, Nikola ; Matoušek, Tomáš (advisor) ; Száková, Jiřina (referee)
Nowadays, arsenic is becoming an important pollutant in the environment. Chronic exposure to arsenic can cause number of serious diseases. Therefore, a development of analytical methods for trace and ultratrace speciation analysis- analysis of individual forms or phases in which As is found in the sample - is fully in place. This Thesis compares four methods of trace speciation analysis, with focus on limits of detection and quantification, and on comparison of results of analysis of river and sea water reference materials. Methods based on hydride generation with preconcentration by cryotrapping and AAS or ICP-MS detection, with limits of detection in ng or tenths of ng·dm-3 , are compared with procedures employing HPLC, with ICP-MS detection. The Thesis includes development and optimization of a pre-reduction step of postcolumn hydride generation with on-line pre-reduction of pentavalent arsenic species, in order to improve sensitivity of this method. Limits of detection around 10 ng·dm-3 are achieved. The results of analyses obtained by individual methods are in excellent agreement. Keywords: Arsenic, speciation analysis, hydride generation, atomic absorption spectrometry, inductively coupled plasma- mass spectrometry, high efficiency liquid chromatography, limits of detection.
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Opioids as model drugs for exploring the mechanism underlying the development of drug dependence
Trojánková, Nikola ; Novotný, Jiří (advisor) ; Hejnová, Lucie (referee)
The aim of this bachelor thesis was to gather knowledge about the mechanisms of addiction, where opioids served as model compounds. Opioids are substances commonly used to treat acute and severe pain as in cancer treatment. However, long-term administration of these drugs killing, after a time reaches the ceiling, which is caused by rapid onset of analgesic tolerance and the slow development of tolerance to the secondary side effects. To achieve the same effect has to be constantly increasing dose, leading to the emergence and development of dependence. Mechanisms of drug addiction are still not fully elucidated, but recent studies agree that a very significant role in these events are membrane-bound opioid receptors and adenylyl cyclase signaling system that regulates intracellular levels of cAMP and CREB and FosB as transcription factors. Very important are the so-called epigenetic mechanisms, such as post-translational modification of histones and DNA or gene expression.
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