20 (2014) Scientific papers, Series Ahttps://hdl.handle.net/10195/754122024-03-28T15:09:20Z2024-03-28T15:09:20ZDetermination of trinitrotoluene at ex-situ prepared bismuth film electrode: An initial studySopha, HannaŠvancara, Ivanhttps://hdl.handle.net/10195/754342020-05-20T10:47:21Z2014-01-01T00:00:00ZDetermination of trinitrotoluene at ex-situ prepared bismuth film electrode: An initial study
Sopha, Hanna; Švancara, Ivan
A bismuth film electrode prepared ex-situ on a glassy carbon powder substrate
(BiF-GCPE) was applied to the determination of trinitrotoluene (TNT) in
combination with square-wave adsorptive stripping voltammetry. The
electroanalytical performance of the BiF-GCPE was studied in Britton-Robinson
buffers in the range of pH 4-9, revealing the most favourable stripping signals in
mild alkaline solutions (pH 9.0). For calibration, linear responses could be
obtained in the concentration range of 0.5-5.0 ppm TNT, when using a deposition
time of 60 s (R2 = 0.9999), and within 0.1-1.5 ppm TNT after deposition for 120
s (R2 = 0.9983). The LOD (3F) was estimated to be about 7 ppb (for deposition
time of 240 s), and the BiF-GCPE exhibited a very good repeatability (RSD = ±2.3
%; n = 10, ci = 0.5 ppm). Finally, possible determination of TNT in the presence
of nitrobenzene was also shown.
2014-01-01T00:00:00ZLipidomic analysis of porcine organs using hydrophilic interaction liquid chromatography and mass spectroscopyCífková, EvaHolčapek, MichalLísa, Miroslavhttps://hdl.handle.net/10195/754332020-05-20T10:41:10Z2014-01-01T00:00:00ZLipidomic analysis of porcine organs using hydrophilic interaction liquid chromatography and mass spectroscopy
Cífková, Eva; Holčapek, Michal; Lísa, Miroslav
The identification and quantitation of all lipids in complex biological tissues is the
first step towards the understanding how lipids function in a biological system and
the elucidation of the mechanism of lipid-related diseases including obesity,
atherosclerosis, cancer, cardiovascular diseases, etc. Our optimized nontargeted
method using hydrophilic interaction liquid chromatography (HILIC) coupled to
electrospray ionization mass spectrometry (ESI-MS) was used for the
characterization of the lipidome, mainly glycerophospholipids and sphingolipids
in porcine brain, heart, kidney, liver, lung, spinal cord, spleen and stomach.
Individual lipid classes are quantified based on the peak integration of individual
lipid classes separated in the HILIC mode multiplied by their response factors and
correlated by sphingosylethanolamine (d17:1/12:0) as a single internal standard.
Subsequently, relative abundances of deprotonated molecules [M-H]– in negativeion
ESI mass spectra are used for determination of lipid species concentration
inside individual classes. The approach using [M-H]– ions enables to obtain detailed information about phosphatidylethanolamines and their different forms
of fatty acyl linkage on the glycerol skeleton (plasmalogens and ether analogs),
phosphatidylinositols and hexosylceramides in studied organs. Our results
provide important knowledge about lipid representations in vital porcine organs
and can be applied for future metabolic studies on human to investigate serious
lipid-related human disorders.
2014-01-01T00:00:00ZUtilization of hydrosilated silica-based stationary phases for separation of antioxidantsSoukup, JanJanás, PetrJandera, Pavelhttps://hdl.handle.net/10195/754322020-05-20T09:16:57Z2014-01-01T00:00:00ZUtilization of hydrosilated silica-based stationary phases for separation of antioxidants
Soukup, Jan; Janás, Petr; Jandera, Pavel
We studied the influence of mobile phase composition on the retention of phenolic
acids and flavonoid compounds on five different hydrosilated silica-based
stationary phases in buffered aqueous acetonitrile. Cogent UDC cholesterolTM,
Cogent bidentate C18TM and Cogent Phenyl hydrideTM columns show significant
dual reversed-phase/normal-phase retention behaviour, while Cogent Diamond
hydrideTM and Cogent Silica-CTM columns provide very low retention in the
reversed-phase mode. The effect of the aqueous acetate buffer concentration on
retention factors of phenolic acids and flavonoid compounds over the full mobile
phase composition range, including both aqueous normal-phase (ANP) and
reversed-phase (RP) mechanisms, can be described by a four-parameter equation
for dual-retention mechanism. At increasing temperature, the retention factors
and peak widths decrease in the aqueous normal-phase range. In agreement with
van’t Hoff model, linear ln k versus 1/T plots were observed, showing a single retention mechanism. From among the stationary phases tested, Cogent UDC
cholesterolTM column has high temperature stability (up to 100 °C) and provides
the most selective and efficient separations of flavones in the ANP mode and
Cogent Diamond hydrideTM is the most selective and effective for separation of
phenolic acids.
2014-01-01T00:00:00ZModification reactions applicable to polymeric monolithic columns. A reviewCurrivan, SinéadJandera, Pavelhttps://hdl.handle.net/10195/754312020-05-20T09:10:38Z2014-01-01T00:00:00ZModification reactions applicable to polymeric monolithic columns. A review
Currivan, Sinéad; Jandera, Pavel
Organic monolithic columns can be prepared from co-polymerizations of
functional monomer and a cross-linker, resulting in a desired surface
functionality. They can also be prepared to form a generic polymer monolith, in
which the functionality can be altered by using a number of post-polymerization
modifications. The reactions used to convert surface functionality include reaction
chemistry, thermal or photo-initiated polymerization reactions, or the addition of
nano-architectures, such as nano-particles or nano-tubes. This review article aims
to highlight the available options in the modification of polymeric monolithic
columns prepared by thermal or UV initiated polymerizations.
2014-01-01T00:00:00Z