ABSTRACT
The separation of different ring numbered polyaromatic hydrocarbons (PAHs) was accomplished by using cetyltrimethylammonium bromide (CTAB) in capillary electrokinetic chromatography. In order to increase the solubilities and selectivities of PAHs, acetonitrile (ACN) was used as an organic modifier. Under the optimised conditions, 11 aromatic compounds were separated within 14.5min in a running electrolyte containing 10mM phosphate, 30mM CTAB, and 40% ACN at pH 6.0. The effects of CTAB and ACN concentrations, voltage and pH on the resolution were investigated. Reproducibilities of migration times range between 0.55 and 1.27 R.S.D.% and peak areas between 1.02 and 7.23 R.S.D.%. Limit of detections (LODs) range between 0.09 and 2.24mugml(-1). This new and fast separation method of PAHs was applied to cooked oil sample.
ABSTRACT
A new, simple and rapid capillary electrophoresis method was developed for the identification and quantitative determination of two medically active constituents-khellin and visnagin-in the extracts of Ammi visnaga fruits. Micellar electrochromatographic separation of khellin and visnagin was carried out using 10 mmol/l borate, 50 mmol/l sodium dodecylsulfate, 25% (v/v) acetonitrile at pH 9 as running buffer. Ammi visnaga fruits were extracted with methanol and the extracts were directly injected without any purification and pre-separation processes. Coumarin was used as internal standard for quantitation and the limits of detection for khellin and visnagin were 2.36 and 1.97 microg/ml, respectively using UV detection at 245 nm.
Subject(s)
Ammi/chemistry , Electrophoresis, Capillary/methods , Khellin/analogs & derivatives , Khellin/analysis , Sensitivity and SpecificityABSTRACT
Sodium dodecylbenzenesulfonate (SDBS) was used as an additive in separating a broad range of polycyclic aromatic hydrocarbons (PAHs) by capillary electrophoresis. In the absence of micelles, using an acetonitrile-water (40:60) electrolyte, the separation mechanism was predicted as solvophobic association of the PAH molecules with hydrophobic chains of the SDBS surfactant and a possible pi-pi interaction between aromatic groups of PAHs and SDBS. The effects of voltage, acetonitrile and SDBS concentrations on separation were investigated. SDBS provides a good selectivity for PAHs not only between different ring numbers (1 to 5) but also between the pairs of structural isomers. Under optimum conditions, 11 aromatic compounds were separated with efficiencies between 130,000 and 230,000 theoretical plates. Reproducibilities of migration times range between 1.15 and 1.55% RSD and peak areas between 2 and 9% RSD.
Subject(s)
Benzenesulfonates/chemistry , Chromatography, Micellar Electrokinetic Capillary/methods , Polycyclic Compounds/isolation & purification , SolubilityABSTRACT
Separation and detection of lanthanides by capillary zone electrophoresis in the presence of pyridine-2-carboxylic acid (picolinic acid) as UV-absorbing complexing agent were investigated. The resolution of partially complexed positively charged complexes is improved by using two buffer ligands competing with picolinic acid for metal ions. When hydroxyisobutyric acid (HIBA) and formic acid are used together as competing ligands, this provides complete separation of all 14 lanthanides with good peak shapes. An on-column separation of 14 lanthanides was achieved in only 9 min using 0.8 mmol/l picolinic acid, 10 mmol/l HIBA and 25 mmol/l formic acid at pH 4.7. Determination of lanthanide complexes was performed by direct detection at 210 nm. Detection limits (signal-to-noise ratio=3) are ca. 0.53-0.96 microg/ml.
Subject(s)
Electrophoresis, Capillary/methods , Lanthanoid Series Elements/isolation & purification , Picolinic Acids/chemistry , Spectrophotometry, Ultraviolet/methods , Formates/chemistry , Lanthanoid Series Elements/analysisABSTRACT
Separation and detection of lanthanides by capillary zone electrophoresis in the presence of cupferron (N-nitroso-N-phenylhydroxylamine) as UV absorbing complexing agent were investigated. The resolution of partially complexed positively charged cupferron complexes is improved by using a buffer ligand competing with cupferron for metal ions. When hydroxyisobutyric acid (HIBA) is used as buffer and competing ligand, it provides complete separation of all 14 lanthanides with good peak shapes. An on-column separation of 14 lanthanides was achieved in only 7 min using 0.1 mmol/l cupferron, 15 mmol/1 HIBA at pH 4.9. The separation efficiencies for the optimum separation condition are between 77,000 and 208,000 theoretical plates. Determination of lanthanide complexes was performed by direct UV detection at 210 nm. Detection limits (signal-to-noise ratio=3) are ca. 0.24-0.47 microg/ml for lanthanides. Under optimum conditions, the complete separation of thorium and uranium from mixed lanthanides was achieved.
Subject(s)
Metals, Rare Earth/isolation & purification , Nitrosamines/chemistry , Spectrophotometry, Ultraviolet/methods , Metals, Rare Earth/chemistryABSTRACT
The suitability of the vacancy affinity capillary electrophoretic method (VACE) for study of displacement of a target drug from a protein by simultaneously administered drugs was investigated. As test system, the displacement of warfarin from bovine serum albumin (BSA) by furosemide and phenylbutazone was selected. It appears that the displacement can be observed well from the shift of the actual mobility of warfarin when a displacer drug is added. Also, the competitive action of the displacer drugs (affinity for BSA) is clearly visible. The VACE method seems to be attractive for rapid assessment of information about the competitive properties of coadministered compounds.
Subject(s)
Electrophoresis, Capillary/methods , Pharmaceutical Preparations/metabolism , Protein Binding , Animals , Binding, Competitive , Cattle , Evaluation Studies as Topic , Furosemide/metabolism , Phenylbutazone/metabolism , Serum Albumin/metabolism , Warfarin/metabolismABSTRACT
A study of the capillary electrophoretic separations of proteins and peptides using high-molecular-mass polyethyleneimine (PEI) is presented. Experiments were performed in the PEI-coated capillaries together with the use of this polymer as a buffer additive under different separation conditions. The effects of pH and the concentration of PEI in the buffer on the electroosmotic flow and the migration orders of biopolymers were investigated. The use of the cationic polymer offers an alternative for the modification of the separation selectivity and resolution of biopolymers.