The influence of experimental conditions on chromatographic behaviour of promising oligodeoxynucleotide double-labelled molecular probes containing an azaphthalocyanine macrocycle as a perspective dark quencher was studied. A recently introduced new stationary phase based on styrene-divinylbenzene copolymer was tested. The planar and hydrophobic structure of the azaphthalocyanine is considerably different from those of currently used fluorophores and quenchers. Thus, the most challenging issue was the separation of the double-labelled probe from its main impurity represented by a mono-labelled probe, containing only the azaphthalocyanine macrocycle. The absorbance measurement cannot simply determine this impurity, and its presence fundamentally compromises the biological assay. The commonly used gradient elution was not suitable and isocratic conditions seemed to be more appropriate. The azaphthalocyanine moiety influences the properties of the modified oligodeoxynucleotides substantially, and thus their chromatographic behaviour was determined predominantly by this quencher. Acetonitrile was the preferred organic solvent for the analysis of probes containing the azaphthalocyanine quencher and the effect of ion-pairing reagents was dependent on the probe structure. The temperature seemed to be an effective parameter for fine-tuning of the separation and mass transfer improvement. Generally, our findings could be helpful in method development for purity evaluation of double-labelled oligodeoxynucleotide probes and semipreparative methods.
- MeSH
- acetonitrily chemie MeSH
- aza sloučeniny * analýza chemie MeSH
- fluorescenční barviva * analýza chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- molekulární sondy * analýza chemie MeSH
- oligodeoxyribonukleotidy * analýza chemie MeSH
- rozpouštědla MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
A set of new mixed-mode ion-exchange stationary phases is presented. The backbone of organic selectors is formed by a linear hydrocarbon chain, which is divided into two parts of various lengths by a heteroatom (oxygen or nitrogen). In all studied cases, there is a sulfonic acid moiety as the terminal group. Therefore, selectors bearing oxygen gave rise to strong cation ion-exchange stationary phases, while selectors with an embedded nitrogen atom (inducing a weak anion exchange capacity) were used to create zwitterion ion-exchange stationary phases. The new mixed-mode stationary phases were chromatographically evaluated in high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) using isocratic elution conditions to disclose their chromatographic potential. In HPLC mode, aqueous-rich reversed phase chromatography, acetonitrile-rich hydrophilic interaction liquid chromatography and methanolic ion-exchange chromatography mobile phases were employed. In these chromatographic modes, retention factors and selectivity values for a test set of basic and zwitterionic analytes were determined. The results were compared and principal component analysis for each chromatographic mode was performed. For all chromatographic modes, the component 1 in the principal component analysis reflected the elution order. The application of different mobile phases on a particular column resulted not only in variation in retention, but also in modified selectivity, and different elution order of the analytes. The orthogonality of the elution order depending on the employed mobile phase conditions was especially reflected for structurally closely related analytes, such as melatonin and N-acetyl-serotonin, tryptamine and serotonin or noradrenalin and octopamine. However, ion-exchange interactions remain the main driving force for retention. From all investigated stationary phases, the SCX 2 (C5-linker and C4-spacer) seems to be the best choice for the separation of basic analytes using different mobile phase conditions.
- MeSH
- acetonitrily chemie MeSH
- anionty chemie MeSH
- biogenní aminy izolace a purifikace MeSH
- chemie farmaceutická metody MeSH
- chromatografie metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- iontová výměna MeSH
- kationty chemie MeSH
- léčivé přípravky chemie izolace a purifikace MeSH
- methanol chemie MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
Double and triple bonds have significant effects on the biological activities of lipids. Determining multiple bond positions in their molecules by mass spectrometry usually requires chemical derivatization. This work presents an HPLC/MS method for pinpointing the double and triple bonds in fatty acids. Fatty acid methyl esters were separated by reversed-phase HPLC with an acetonitrile mobile phase. In the APCI source, acetonitrile formed reactive species, which added to double and triple bonds to form [M + C3H5N]+• ions. Their collisional activation in an ion trap provided fragments helpful in localizing the multiple bond positions. This approach was applied to fatty acids with isolated, cumulated, and conjugated double bonds and triple bonds. The fatty acids were isolated from the fat body of early-nesting bumblebee Bombus pratorum and seeds or seed oils of Punicum granatum, Marrubium vulgare, and Santalum album. Using the method, the presence of the known fatty acids was confirmed, and new ones were discovered.
- MeSH
- acetonitrily chemie MeSH
- estery chemie izolace a purifikace MeSH
- hmotnostní spektrometrie MeSH
- mastné kyseliny chemie izolace a purifikace MeSH
- molekulární struktura MeSH
- včely chemie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A simple and rapid ultra-high-performance liquid chromatography coupled with mass spectrometry method was developed for acyclovir and its metabolite 9-carboxymethoxymethylguanine in human serum. After precipitation of serum samples with 0.1% formic acid in acetonitrile/methanol (40:60, v/v), components were separated on a Luna Omega C18 column (1.6 μm; 2.1 × 150 mm) at 40°C. Mobile phase A (2 mmol/L ammonium acetate, 0.1% formic acid in 5% acetonitrile, v/v/v) and mobile phase B (2 mmol/L ammonium acetate, 0.1% formic acid in 95% acetonitrile, v/v/v) were used for gradient elution. A linear calibration curve was obtained over the range of 0.05-50 mg/L, and the correlation coefficients were better than 0.999. The limit of quantitation was 0.05 mg/L for both analytes. The intra- and interday accuracy and precision at three concentration levels ranged between 1.6 and 13.3%, and recoveries were achieved with a range between 92.2 and 114.2%. This method was developed and validated for the therapeutic monitoring of acyclovir in patients.
- MeSH
- acetonitrily chemie MeSH
- acyklovir analýza MeSH
- chemické techniky analytické normy MeSH
- dospělí MeSH
- formiáty chemie MeSH
- guanin analogy a deriváty analýza MeSH
- hmotnostní spektrometrie MeSH
- kalibrace MeSH
- lidé středního věku MeSH
- lidé MeSH
- limita detekce MeSH
- mladiství MeSH
- mladý dospělý MeSH
- reprodukovatelnost výsledků MeSH
- řízení kvality MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The advantages of using mixtures of organic solvents for the separation of labeled oligosaccharides on the amide stationary phase under hydrophilic interaction liquid chromatography conditions are presented. The effect of the type of buffer as well as solvent or their mixtures on retention of uracil, saccharide labeling reagents (2-aminobenzoic acid, 2-aminobenzamide, ethyl 4-aminobenzoate, procainamide), and corresponding labeled saccharides were evaluated. The successful isocratic separation of labeled isomeric trisaccharides (maltotriose, panose, and isomaltotriose) was achieved in the mobile phase consisting of a 90% (v/v) mixture of organic solvents (methanol/acetonitrile 60:40) and 10% (v/v) 30 mM ammonium formate, pH 3.3. Changing the volume ratio between methanol/acetonitrile from 60:40 to 50:50 (v/v) allowed to obtain the separation of di-, tri-, and tetrasaccharides labeled by ethyl 4-aminobenzoate in less than 10.5 min.
- MeSH
- acetonitrily chemie MeSH
- amidy chemie MeSH
- chemické techniky analytické přístrojové vybavení metody MeSH
- chromatografie kapalinová * MeSH
- formiáty chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- isomerie MeSH
- oligosacharidy izolace a purifikace MeSH
- ortoaminobenzoáty chemie MeSH
- rozpouštědla chemie MeSH
- sacharidy chemie MeSH
- Publikační typ
- časopisecké články MeSH
The liquid state NMR chemical shift of protons is a parameter frequently used to characterize host-guest complexes. Its theoretical counterpart, that is, the 1H NMR chemical shielding affected by the solvent (1H CS), may provide important insights into spatial arrangements of supramolecular systems, and it can also be reliably obtained for challenging cases of an aggregation of aromatic and antiaromatic molecules in solution. This computational analysis is performed for the complex of coronene and an antiaromatic model compound in acetonitrile by employing the GIAO-B3LYP-PCM approach combined with a saturated basis set. Predicted 1H CS values are used to generate volumetric data, whose properties are thoroughly investigated. The 1H CS isosurface, corresponding to a value of the proton chemical shift taken from a previous experimental study, is described. The presence of the 1H CS isosurface should be taken into account in deriving structural information about supramolecular hosts and their encapsulation of small molecules.
- MeSH
- acetonitrily chemie MeSH
- difrakce rentgenového záření MeSH
- izotopy uhlíku MeSH
- magnetická rezonanční spektroskopie metody MeSH
- makromolekulární látky MeSH
- nikl chemie MeSH
- normální rozdělení MeSH
- polycyklické sloučeniny chemie MeSH
- protonová magnetická rezonanční spektroskopie MeSH
- protony MeSH
- rozpouštědla chemie MeSH
- železo chemie MeSH
- Publikační typ
- časopisecké články MeSH
Asymmetric and symmetric dimethylarginines are toxic non-coded amino acids. They are formed by post-translational modifications and play multifunctional roles in some human diseases. Their determination in human blood plasma is performed using capillary electrophoresis with contactless conductivity detection. The separations are performed in a capillary covered with covalently bonded PAMAPTAC polymer, which generates anionic electroosmotic flow and the separation takes place in the counter-current regime. The background electrolyte is a 750 mM aqueous solution of acetic acid with pH 2.45. The plasma samples for analysis are treated by the addition of acetonitrile and injected into the capillary in a large volume, reaching 94.5% of the total volume of the capillary, and subsequently subjected to electrophoretic stacking. The attained LODs are 16 nm for ADMA and 22 nM for SDMA. The electrophoretic resolution of both isomers has a value of 5.3. The developed method is sufficiently sensitive for the determination of plasmatic levels of ADMA and SDMA. The determination does not require derivatization and the individual steps in the electrophoretic stacking are fully automated. The determined plasmatic levels for healthy individuals vary in the range 0.36-0.62 µM for ADMA and 0.32-0.70 µM for SDMA.
Mass spectrometry (MS) is a powerful and sensitive method often used for the identification of phosphoproteins. However, in phosphoproteomics, there is an identified need to compensate for the low abundance, insufficient ionization, and suppression effects of non-phosphorylated peptides. These may hamper the subsequent liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analysis, resulting in incomplete phosphoproteome characterization, even when using high-resolution instruments. To overcome these drawbacks, we present here an effective microgradient chromatographic technique that yields specific fractions of enriched phosphopeptides compatible with LC-MS/MS analysis. The purpose of our study was to increase the number of identified phosphopeptides, and thus, the coverage of the sample phosphoproteome using the reproducible and straightforward fractionation method. This protocol includes a phosphopeptide enrichment step followed by the optimized microgradient fractionation of enriched phosphopeptides and final LC-MS/MS analysis of the obtained fractions. The simple fractionation system consists of a gas-tight microsyringe delivering the optimized gradient mobile phase to reversed-phase microcolumn. Our data indicate that combining the phosphopeptide enrichment with the microgradient separation is a promising technique for in-depth phosphoproteomic analysis due to moderate input material requirements and more than 3-fold enhanced protein identification.
- MeSH
- acetonitrily chemie MeSH
- chemická frakcionace metody MeSH
- chromatografie kapalinová metody MeSH
- fosfopeptidy chemie MeSH
- fosfoproteiny metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- proteom MeSH
- proteomika MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- titan chemie MeSH
- tlak MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The composition of a sample solvent has a crucial impact on separations in hydrophilic interaction liquid chromatography (HILIC). In this short communication, we studied the effect of an organic modifier in the sample solvent on the solubility of different tryptic glycopeptides of hemopexin and haptoglobin proteins. The results showed that the solubility of glycopeptides in solvents with a high acetonitrile content depends on the type of attached N-glycan. We observed lower solubility in larger glycans attached to the same peptide backbone, and we demonstrated that glycopeptides containing sialic acids precipitate more readily than those without sialic acid. Therefore, the sample solvent composition in HILIC must be carefully optimized for accurate quantitative data collection and for adequate separation.
- MeSH
- acetonitrily chemie MeSH
- glykopeptidy analýza chemie izolace a purifikace MeSH
- hydrofobní a hydrofilní interakce MeSH
- kyselina N-acetylneuraminová chemie MeSH
- polysacharidy chemie MeSH
- rozpouštědla chemie MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
A rapid procedure for the determination of 2-aminoisobutyric acid in enzalutamide bulk drug substance based on hydrophilic interaction chromatography with fluorescence detection was developed. Fluorescence detection after postcolumn derivatization with o-phthaldialdehyde/2-mercaptoethanol was carried out at excitation and emission wavelength of 345 nm and 450 nm, respectively. The postcolumn reaction conditions such as reaction temperature, mobile phase and derivatization reagent flow rate and the reagents concentrations were studied and optimized due to steric hindrance of amino group of 2-aminoisobutyric acid. The derivatization reaction was applied for the hydrophilic interaction chromatography method which was based on COSMOSIL HILIC column with a mobile phase consisting of a mixture of 25 mmol/L acetic acid adjusted to pH 5.5 (using 1 mol/L potassium hydroxide) and acetonitrile using an isocratic elution (28:72, ν/ν). The benefit of the reported approach consists in a simple sample pretreatment and a quick and sensitive hydrophilic interaction chromatography method. The developed method was validated in terms of linearity, limit of detection, limit of quantification, accuracy, precision and selectivity according to the International Conference on Harmonisation guidelines. The developed method was demonstrated to be applied for the analysis of 2-AIBA in routine quality control evaluation of commercial samples of enzalutamide bulk drug substance.
- MeSH
- acetonitrily chemie MeSH
- antagonisté androgenních receptorů analýza chemie MeSH
- fenylthiohydantoin analogy a deriváty analýza chemie MeSH
- fluorescenční spektrometrie přístrojové vybavení metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- kontaminace léku prevence a kontrola MeSH
- kyseliny aminoisomáselné analýza MeSH
- limita detekce MeSH
- merkaptoethanol chemie MeSH
- o-ftalaldehyd chemie MeSH
- reprodukovatelnost výsledků MeSH
- řízení kvality * MeSH
- vysokoúčinná kapalinová chromatografie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
