The capabilities of in-capillary chiral derivatization of amino acids using
ortho
-phthalaldehyde and
N
-acetyl-L-cysteine are discussed. The influence of the concentration of a borate buffer ...solution and the addition of 2-hydroxypropyl-β-cyclodextrin and α-cyclodextrin to the supporting electrolyte on the selectivity of separation of the resulting diastereomeric derivatives was revealed. The found conditions were adapted to the electrophoretic analysis of the culture liquid of
Escherichia coli
bacteria for the detection of amino acids produced by them. Tyrosine, alanine, serine, and glutamic acid were identified. An important result is the detection of D-serine and D-alanine in the culture liquid.
Hydrophilic Interaction Chromatography Kartsova, L. A.; Bessonova, E. A.; Somova, V. D.
Journal of analytical chemistry (New York, N.Y.),
05/2019, Letnik:
74, Številka:
5
Journal Article
Recenzirano
Hydrophilic interaction liquid chromatography (HILIC), which includes the distribution, adsorption, ion exchange, and exclusion of analytes, has gained active development recently. The review covers ...the principles of the method, types of stationary and mobile phases, mechanisms of retention of highly polar compounds under HILIC conditions, implementation of 2D chromatography, and also fields of application of the method.
Keywords
: hydrophilic chromatography, retention mechanism, reverse phase HPLC, normal phase mode, HILIC stationary phases, zwitterionic phases, high polar analytes
The review discusses the advantages and limitations of chromatographic and electrophoretic approaches to the determination of neutral carbohydrates in various samples with complex matrices, the ...possibility of implementing a variety of liquid chromatography and capillary electrophoresis modes (in zone and micellar versions), and their combinations with various derivatization, detection, and sample preparation techniques. Conditions for the indirect detection of sugars upon the introduction of various absorbing additives into a mobile phase or supporting electrolyte, ligand-exchange capillary electrophoresis, and intracapillary complexation and the determination of carbohydrates by anion-exchange and hydrophilic chromatography are discussed.
The use of modifiers in the electrophoretic separation of multicomponent mixtures makes it possible to significantly expand the analytical capabilities of capillary electrophoresis. Modifiers of ...electrophoretic systems, different in nature and properties, can perform different functions: form stationary and pseudo-stationary phases, prevent the adsorption of analytes on the walls of a quartz capillary, help to reduce the limits of detection for analytes during preconcentration, etc. In this review, various versions of the application of modifiers to the electrophoretic separation and preconcentration of analytes of different nature are considered on an example of imidazolium ionic liquids, which can act as stationary and pseudo-stationary phases, and also directly participate in the online preconcentration of analytes of hydrophilic and hydrophobic nature.
Biomedicine is one of the most rapidly evolving fields in medicine with a strong focus on diagnostics. Capillary electrophoresis (CE) is a separation technique widely used for determining ...concentrations of biologically active compounds, pharmaceuticals, microorganisms, and their metabolites in biological fluids. Today, CE is widely employed in the diagnosis of various diseases. Additionally, it has become an important tool in the pharmaceutical industry, especially for assessing the enantiopurity of drugs. The main advantages of CE include an ability of the automation and miniaturization of an analysis, compatibility with mass-spectrometric detection, use of small sample volumes (nanoliters), and the availability of the equipment and consumables. This review summarizes the key areas of CE application to biomedicine, including proteomic and metabolomic studies, and examines its prospects for the ultra-miniaturization and automation of enantiomeric analysis, including the use of microelectronics and microfluidic systems.
Ionic liquids (ILs) are widely used in separation methods such as chromatography and capillary electrophoresis due to their unique properties. This review discusses the prospects for using ...imidazole-based ILs as electrophoretic system modifiers in capillary zone electrophoresis and micellar and microemulsion electrokinetic chromatography for the determination of biologically active substances (amino acids, catecholamines, steroid hormones, and polyphenolic antioxidants). New approaches to selective electrophoretic determination and efficient online preconcentration of analytes with the participation of imidazolium ILs are considered; the application of developed approaches to the analysis of natural objects (urine, blood plasma, and plant extracts) is exemplified.
It is found that ionic liquids (ILs) based on imidazole can be used as extractants in the dispersive liquid–liquid microextraction of combined pesticide preparations (imidacloprid, biphenthrin, ...cypermethrin, malathion, phosalone, and diazinon) followed by their determination by HPLC with electrospray ionization tandem mass spectrometry detection with. The effect of the IL (1-hexyl-3-methylimidazolium tetrafluoborate C
6
MIM BF
4
, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide C
6
MIM NTf
2
, 1‑butyl-3-methylimidazolium hexafluorophosphate, C
4
MIM PF
6
) nature and of the dispersive solvent (acetonitrile, methanol, acetone) volume, extraction time, pH of sample solution, and salting-out agent on the efficiency of analyte extraction is studied. It is found that the maximum recoveries (86–99%) of pesticides were reached using acetonitrile as a dispersive solvent and the C
4
MIM PF
6
ionic liquid as an extractant. The absence of the effect of pH on the distribution of analytes between the water and organic phases confirms the distributive extraction mechanism. The effect of the ionic liquid on the ionization of pesticides is estimated, and conditions of the back extraction of pesticides to hexane are proposed for its reduction.
Versions of the electrophoretic determination of neutral carbohydrates by a method of indirect detection using acridone acetic and folic acids as absorbing additives (
AA
) are proposed. The effects ...of the nature and concentration of AA, alkali, and various modifiers (cetyltrimethylammonium bromide,
CTAB
) and ionic liquids (1-dodecyl-3-methylimidazolium chloride and 1-hexadecyl-3-methylimidazolium chloride) on the electrophoretic parameters of the migration of analytes are studied. The lowest limits of detection for carbohydrates are achieved in a background electrolyte containing 2.5 mM acridone acetic acid, 75 mM KOH, 0.5 mM CTAB, and 5 vol % MeOH, and amount to 4−10 μg/mL with an efficiency of up to 350 thousand t.p. Under the conditions found, samples of buckwheat honey and human blood plasma are analyzed. It is found that in analyzing food products, it is preferable to use folic acid as a AA, because it provides the best selectivity for the separation of carbohydrates: for the sucralose−sucrose pair, the resolution factor is 7.6.
The review considers the main trends in actively developing methods of solid-phase and liquid–liquid microextraction for the extraction, purification, and preconcentration of analytes from medicinal ...plants and plant materials, the use of new extractants and approaches to the preparation of samples of plant origin, and their compatibility with mass-spectrometric detection. Particular attention is paid to the analytical capabilities, advantages, and limitations of each of the approaches to extracting analytes from plant materials for the subsequent analysis of the obtained extracts by chromatography–mass spectrometry.
We propose a version of the simultaneous determination of zoledronic acid and creatinine in serum and plasma samples by hydrophilic chromatography (HILIC). Factors affecting the determination of ...zoledronic acid were found: the composition and concentration of the buffer solution, the nature of the stationary phase, the presence of tartaric acid in the eluent as a complexing agent to prevent the complexation of zoledronic acid with metal ions. We determined the linear concentration ranges for zoledronic acid and creatinine and their limits of detection. The following conditions for chromatographic analysis were found: amide stationary phase; a 5 mM phosphate buffer solution, 2 mM tartaric acid (pH 7.0)/CH
3
CN; gradient 90–70% of CH
3
CN.
