sodium-dodecyl-sulfate and sodium-borate

An alternative method for simultaneous baseline separation of α and β-acids homologues and isomers in hop by CD-MEKC with UV detection was proposed. The optimized background electrolyte was composed of 30 mmol/L sodium tetraborate solution, 45 mmol/L sodium dodecyl sulfate, 20 mmol/L β-cyclodextrin and 10% v/v acetonitrile. The instrumental conditions were evaluated by using a 3

Topics: Acids; beta-Cyclodextrins; Borates; Chromatography, Micellar Electrokinetic Capillary; Electrophoresis, Capillary; Humulus; Isomerism; Sodium Dodecyl Sulfate; Spectrophotometry, Ultraviolet

This report describes the use of surfactant-coated graphitized multiwalled carbon nanotubes (SC-GMWNTs) as a novel pseudostationary phase in CE with diode array detection for the determination of phenolic acids and tanshinones in herbal and urine samples. Several parameters influencing the separation were studied, such as the concentrations of SDS, GMWNTs, and isopropanol; choice of carbon nanotubes; sodium borate content; and buffer pH. The results revealed that the presence of SC-GMWNTs in buffer enhanced the separation efficiency for the target analytes relative to conventional micelles due to the strong interaction between the surface of the GMWNTs and the target compounds. Under the optimum conditions, the method showed good linearity, with correlation coefficients higher than 0.9950. LODs were in the range of 0.71-3.10 μg/mL. Furthermore, satisfactory separations were achieved with good recovery values in the range of 89.97 and 103.30% when 10 mM borate, 30 mM SDS, 10% isopropanol, and 6 μg/mL SC-GMWNTs were introduced into the buffer solution.

Topics: 2-Propanol; Animals; Borates; Buffers; Drugs, Chinese Herbal; Electrophoresis, Capillary; Graphite; Hydrogen-Ion Concentration; Limit of Detection; Male; Microscopy, Electron, Scanning; Nanotubes, Carbon; Phytochemicals; Rats, Sprague-Dawley; Reproducibility of Results; Salvia miltiorrhiza; Sodium Dodecyl Sulfate; Surface-Active Agents

Micellar electrokinetic chromatography fingerprinting combined with quantification was successfully developed and applied to monitor the quality consistency of Weibizhi tablets, which is a classical compound preparation used to treat gastric ulcers. A background electrolyte composed of 57 mmol/L sodium borate, 21 mmol/L sodium dodecylsulfate and 100 mmol/L sodium hydroxide was used to separate compounds. To optimize capillary electrophoresis conditions, multivariate statistical analyses were applied. First, the most important factors influencing sample electrophoretic behavior were identified as background electrolyte concentrations. Then, a Box-Benhnken design response surface strategy using resolution index RF as an integrated response was set up to correlate factors with response. RF reflects the effective signal amount, resolution, and signal homogenization in an electropherogram, thus, it was regarded as an excellent indicator. In fingerprint assessments, simple quantified ratio fingerprint method was established for comprehensive quality discrimination of traditional Chinese medicines/herbal medicines from qualitative and quantitative perspectives, by which the quality of 27 samples from the same manufacturer were well differentiated. In addition, the fingerprint-efficacy relationship between fingerprints and antioxidant activities was established using partial least squares regression, which provided important medicinal efficacy information for quality control. The present study offered an efficient means for monitoring Weibizhi tablet quality consistency.

Topics: Antioxidants; Borates; Chromatography, Micellar Electrokinetic Capillary; Drugs, Chinese Herbal; Electrolytes; Least-Squares Analysis; Multivariate Analysis; Plant Extracts; Quality Control; Reproducibility of Results; Sodium Dodecyl Sulfate; Sodium Hydroxide; Tablets

MEKC was used for the separation of nine acetylcholinesterase inhibitors (AChEIs). AChEIs are an important group of drug compounds that are used medicinally to treat Alzheimer's disease and Myasthenia Gravis. At the time of the experiment, this is the first time that nine AChEIs are used simultaneously in a study. Several chromatographic parameters, such as buffer concentration, pH, surfactants and their concentration, background electrolyte composition, etc., were evaluated to optimize the separation. The optimum separation of the nine AChEIs was achieved in less than 15 min by using 12.5 mM Na(2)HPO(4), 12.5 mM Na(2)B(4)O(7) and 20 mM SDS at pH 10, an applied voltage of 30 kV and a temperature of 25 °C. The reproducibility of the method was also evaluated by computing the RSDs of the migration times and the areas of the nine analyte-peaks, and the migration time and the area of the peak that corresponds to rivastigmine added in the blood sample. The RSD values of the migration times and the peak areas were less than 2% and 6%, respectively, in most cases. The limits of detection and quantification were 0.5 μg/mL and 1.7 μg/mL, respectively. The MEKC method developed was applied to a real blood sample that was obtained from a patient who was not under any of this medication. The sample was spiked with rivastigmine in order to establish the ability of the method to separate the drug from other components that might exist in the blood sample.

Topics: Borates; Cholinesterase Inhibitors; Chromatography, Micellar Electrokinetic Capillary; Humans; Hydrogen-Ion Concentration; Phosphates; Reproducibility of Results; Sensitivity and Specificity; Sodium Dodecyl Sulfate; Temperature

Microemulsion electrokinetic chromatography (MEEKC) has been developed for fingerprint analysis of resina draconis, a substitute for sanguis draconis in the Chinese market. The microemulsion as the running buffer was made up of 3.3% (w/v) sodium dodecyl sulfate (SDS), 6.6% (w/v) n-butanol, 0.8% (w/v) n-octane, and 10 mmol/L sodium tetraborate buffer (pH 9.2), which was also used as the solvent for ultrasonic extraction of both water- and fat-soluble compounds in the traditional Chinese medicine samples. Four batches of resina draconis obtained from different pharmaceutical factories located in different geographic regions were used to establish the electrophoretic fingerprint. MEEKC was performed using a Beckman PACE/MDQ system equipped with a diode-array detector and with monitoring at 280 nm. The fingerprint of resina draconis comprised 27 common peaks within 100 min. The relative standard deviations of the relative migration time of these common peaks were less than 2.1%. Through repetitive injection of the sample solution six times in 24 h, all relative standard deviations of the migration time and peak area of loureirin A and loureirin B were less than 2.5 and 3.8%, which demonstrated that the method had good stability and reproducibility. The relative peak areas of these common peaks in the electropherograms of four batches of resina draconis were processed with two mathematical methods, the correlation coefficient and the interangle cosine, to valuate the similarity. The values of the similarity degree of all samples were more than 0.91, which showed resina draconis samples from different origins were consistent. On the other hand, high-performance liquid chromatography (HPLC) coupled with photodiode-array detection was also applied to establish the fingerprint of resina draconis. The samples were separated with a LiChrospher C(18) column using acetonitrile (solvent A) and water containing 0.1% H(3)PO(4) (solvent B) as the mobile phase in linear gradient elution mode at a flow rate of 0.6 mL/min and detection was at 280 nm. There were only 20 common peaks in the HPLC fingerprint, and the values of the similarity degree of all samples were also more than 0.91. Though the similarity results of fingerprint analysis seemed to be the same, MEEKC resulted in more common peaks and higher separation efficiency for a variety of polarities of the components than HPLC. So, MEEKC was more suitable for development of the fingerprint of resina draconis.

Topics: 1-Butanol; Acetonitriles; Borates; Buffers; Chromatography, High Pressure Liquid; Chromatography, Micellar Electrokinetic Capillary; Dracaena; Drugs, Chinese Herbal; Hydrogen-Ion Concentration; Octanes; Phosphoric Acids; Plant Extracts; Sodium Dodecyl Sulfate; Solvents; Time Factors

In this work, a new chiral micellar electrokinetic chromatography with laser-induced fluorescence detection (chiral-MEKC-LIF) method is proposed to identify and quantify D- and L-amino acids in three lines of transgenic maize and their corresponding nontransgenic parental lines grown under identical conditions. The optimized procedure includes amino acids extraction, derivatization with FITC and chiral-MEKC-LIF separation in a background electrolyte composed of 100 mM sodium tetraborate, 80 mM SDS, and 20 mM beta-CD at pH 10.0. The D- and L-forms of Arg, Ser, Ala, Glu, and Asp, corresponding to the majority amino acids usually found in maize, are separated in less than 25 min with efficiencies up to 890,000 plates/m and high sensitivity (i.e., LODs as low as 160 nM were obtained for D-Arg for a signal-to-noise ratio of three), allowing the detection of 1% D-Arg in the presence of 99% of its opposite enantiomer. Using this method, different D-amino acids are detected in all investigated maize samples providing the reproducible quantification of the D-enantiomeric excess (% d-aa) for each amino acid calculated as % D-aa = 100D-aa/(D-aa + L-aa). Thus, significant differences were observed among the % d-aa values for the different conventional varieties (Aristis, Tietar, and PR33P66 maize) as could be expected from their natural variability. More interestingly, comparing each conventional maize with its corresponding transgenic line, very similar % D-aa values were obtained for one of the studied maize couples (Tietar vs Tietar-Bt) what could be presented as a new proof of their substantial equivalence. However, significant differences in the % d-aa values were observed for the other lines of maize studied. It is concluded that enantioselective procedures can open new perspectives in the study of transgenic organisms in order to corroborate (or not) the equivalence with their conventional counterparts.

Topics: Amino Acids; beta-Cyclodextrins; Borates; Chromatography, Micellar Electrokinetic Capillary; Electrolytes; Fluorescein-5-isothiocyanate; Fluorescence; Fluorescent Dyes; Hydrogen-Ion Concentration; Lasers; Plants, Genetically Modified; Sensitivity and Specificity; Sodium Dodecyl Sulfate; Stereoisomerism; Time Factors; Zea mays

The formation of D-amino acids (D-aa's) in many fermented foods depends, among other factors, on the particular fermentation conditions, the action and autolysis of the microorganisms involved. In this sense, the analysis of chiral amino acids is an interesting analytical strategy for food scientists, since these compounds can be used as bacterial markers and can help, e.g., to detect adulterations, microbiological contaminations, etc. In this work, a fast and sensitive method based on MEKC-LIF has been developed to analyze and quantitate L-amino acid (L-aa) and D-aa in vinegars. The chiral MEKC-LIF procedure uses 100 mM sodium tetraborate, 30 mM SDS, and 20 mM beta-CD at pH 9.7 as running buffer, obtaining a good separation of the main vinegar L-/D-aa previously derivatized with fluorescein isothiocianate. Namely, L/D proline, alanine, arginine, glutamic, and aspartic acid, plus the nonchiral amino acid gamma-aminobutyric acid are separated in less than 20 min with high efficiency (up to 720,000 plates/m) and good sensitivity (LODs lower than 16.6 nM were achieved). Several D-aa's were detected and quantified in balsamic, sherry, white wine, and cider vinegars using this MEKC-LIF procedure, observing interesting differences in their L-aa and D-aa profiles and contents.

Topics: Acetic Acid; Amino Acids; Borates; Chromatography, Micellar Electrokinetic Capillary; Fluorescence; Food Analysis; Hydrogen-Ion Concentration; Lasers; Sensitivity and Specificity; Sodium Dodecyl Sulfate; Stereoisomerism

A rapid, sensitive and reproducible micellar electrokinetic chromatographic method using hexamethyldisilazane as on-line regenerating covalent coating was developed for the quantification of ephedrine (E) and pseudoephedrine (PE). E and PE were derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol for laser-induced fluorescence detection. The on-line regenerating covalent coating formed a combinative double coating with the subsequently produced dynamic SDS coating. The total coating can be easily removed and conveniently regenerated on-line. The simple coating procedure was described. By a series of optimization, a running buffer of 20 mm Na(2)B(4)O(7) + 16 mm SDS was applied for the separation of the derivatives. Linear relationships for E and PE were obtained in the range of 0.044-6.60 microg mL(-1) (correlation coefficients: 0.9975 for E, 0.9981 for PE), and the detection limits for E and PE were 1.71 and 0.67 ng mL(-1), respectively. The separation speed, the reproducibility and the sensitivity were much improved over those of other capillary electrophoresis methods more recently reported. The method was applied to the analysis of the two alkaloids in traditional herbal preparations with recoveries in the range 92.8-104.8%.

Topics: Borates; Chromatography, Micellar Electrokinetic Capillary; Drugs, Chinese Herbal; Ephedrine; Lasers; Organosilicon Compounds; Reproducibility of Results; Sensitivity and Specificity; Sodium Dodecyl Sulfate

A micellar electrokinetic chromatographic (MEKC) method for the simultaneous separation and determination of lamivudine (LMV) and zidovudine (ZDV) in pharmaceutical formulation has been developed. Factors that affect the separation, such as buffer pH, surfactant concentration (sodium dodecyl sulfate, SDS), organic solvents and applied voltage were optimized. Buffer consisting of 12.5 mM sodium tetraborate decahydrate and 15 mM boric acid adjusted at pH 10.8, containing 90 mM SDS and 5% (v/v) acetonitrile (ACN) was found to be suitable for the separation of the drugs. p-Aminobenzoic acid (PABA) was used as internal standard (I.S.). Detection of analytes and I.S. was performed at a wavelength of 210 nm. It was observed that both the drugs and I.S. were migrated within 20 min at the applied voltage of +10 kV. Validation of the method was performed in terms of linearity, accuracy, precision, limit of detection (LOD) and quantification (LOQ). An excellent linearity was obtained in the concentration range 10-80 microg/ml for LMV and 10-100 microg/ml for ZDV. The detection limits for LMV and ZDV were found to be 2.5 and 2.0 microg/ml, respectively. The optimized method was applied to the simultaneous determination of LMV and ZDV in pharmaceutical formulation and human plasma (spiked) samples. Recovery of both the drugs in tablet dosage form and spiked drugs in plasma were > or =99.72% (relative standard deviation (R.S.D.)< or =1.84%) and > or =80.4% (R.S.D.< or =5.4%), respectively. In the electropherogram no interfering peaks were observed in the region of analytes and I.S. due to inactive ingredients in the tablets and matrices in plasma.

Topics: 4-Aminobenzoic Acid; Borates; Boric Acids; Buffers; Chemistry, Pharmaceutical; Chromatography; Chromatography, High Pressure Liquid; Chromatography, Micellar Electrokinetic Capillary; Electrophoresis; HIV Protease Inhibitors; Hydrogen-Ion Concentration; Kinetics; Lamivudine; Micelles; Models, Chemical; Pharmaceutical Preparations; Pressure; Reproducibility of Results; Sodium Dodecyl Sulfate; Solvents; Time Factors; Zidovudine

A selective MEKC method was developed for the analysis of didanosine in bulk samples. Successful separation of didanosine from 13 of its potential impurities, derived from the various synthetic preparation procedures, was achieved. As CZE gave poor separation selectivity, MEKC was preferable. The use of EKC allowed achievement of the separation in a significantly shorter time than conventional HPLC. An anionic long-chain surfactant, lithium dodecyl sulfate (LiDS), was used as the pseudostationary phase and sodium tetraborate buffer as the aqueous phase. In order to obtain the optimal conditions and to test the method robustness, a central composite response surface modeling experiment was performed. The optimized electrophoretic conditions include the use of an uncoated fused-silica capillary with a total length of 40 cm and an ID of 50 microm, a BGE containing 40 mM sodium tetraborate and 110 mM LiDS at pH 8.0, an applied voltage of 18.0 kV, and the capillary temperature maintained at 15 degrees C. The method was found to be robust. The parameters for validation such as linearity, precision, and sensitivity are also reported. Three commercial bulk samples were analyzed with this system.

Topics: Borates; Chromatography, Micellar Electrokinetic Capillary; Didanosine; Methods; Silicon Dioxide; Sodium Dodecyl Sulfate