Júlia Lačná

Capillary electrophoresis in the analysis of biologically important thiols

In this review article, CE methods for analysis of biologically important thiols are overviewed. The article covers the period from the previously published comprehensive review in 2004 until mid‐2016, with emphasis on various detection modes, novel approaches for sample preconcentration, and applications in clinical practice. The most commonly used detection methods, such as conductometry or absorbance detection, although universally applicable and available in most commercial instruments have low sensitivity and have only limited use in thiol analysis. Amperometric and MS detection are more sensitive and have their steady place in thiol analysis, although the mainstay remains CE with LIF detection, reaching nanomolar concentration sensitivities for most of the thiols. Novel probes for CE‐LIF have been developed and tested. The preconcentration approaches using modified gold nanoparticles reaching excellent sensitivities in the picomolar range and various sample stacking methods are also reviewed. Finally, significant clinical applications of the developed methods are discussed with critical insights into the future of CE analysis of thiols.

Sensitive determination of malondialdehyde in exhaled breath condensate and biological fluids by capillary electrophoresis with laser induced fluorescence detection

In this work, a sensitive capillary electrophoresis method with laser induced fluorescence detection for determination of malondialdehyde in various biological fluids was developed. Malondialdehyde reacts with thiobarbituric acid under optimized conditions of pH=2, reaction time of 60min and temperature of 90°C, yielding an adduct that can be separated in a 50mM sodium borate background electrolyte at pH 9. The separation of the formed adduct was accomplished in less than 6min with limit of detection of 1.1nM due to the use of 532nm laser module, exactly matching the maximum excitation wavelength of the formed adduct. The developed method offers unprecedented sensitivity and was for the first time used for analysis of malondialdehyde in exhaled breath condensate. The method proved to be also applicable to other samples of biological fluids, such as blood plasma and saliva.

Study of Various Parameters that Influence the Content of Exhaled breath Condensate Used in the Diagnosis of Gastroesophageal Reflux Disease

Abstract In this work, various parameters that influence the ionic content and pH of exhaled breath condensate in of the noninvasive diagnosis of gastroesophageal reflux disease were studied. Exhaled breath condensate samples were collected using a miniature and inexpensive sampling device. Capillary electrophoresis with contactless conductometric detection was used to monitor the ionic content of exhaled breath condensate. Background electrolyte composed of 20 mM of 2-(N-Morpholino)ethanesulfonic acid, 20 mM of L-Histidine, 2 mM of 18-Crown-6 and 30 M of cetyltrimethylammonium bromide facilitated the rapid separation of anions and cations, both in less than 2 minutes. The possibility of contamination of the exhaled breath condensate by saliva is discussed in detail. The day-to-day repeatability (n=5) of the ionic content and pH of the exhaled breath condensate was studied and was satisfactory, reflecting mainly the physiological variability

Capillary Electrophoretic Analysis of Exhaled Breath Condensate in the Diagnosis of Gastroesophageal Reflux Disease

Abstract In this work, capillary electrophoresis with contactless conductometric detection (CCD) was used for the analysis of the ionic content of exhaled breath condensate (EBC) to differentiate between healthy individuals and patients with gastroesophageal reflux disease (GERD). The exhaled breath condensate was collected using a miniature sample collection device and the content analyzed using a separation electrolyte composed of 20 mM 2-(N-morpholino)ethanesulfonic acid, 20 mM L-histidine, 2 mM 18-Crown-6 and 30 M cetyltrimethylammonium bromide. The separation of anions took less than 2.5 minutes, while the cations were separated in less than 1.5 minutes. The most significantly elevated ions in the group of patients suffering from gastroesophageal reflux disease were chloride, nitrate, propionate and butyrate. Although the number of subjects was too small to draw definite conclusions with regard to the discriminatory power of these ions, the pilot data are promising for EBC as a useful non-invasive alternative for other methods used in the diagnosis of gastroesophageal reflux disease