betadex and acetonitrile

When cyclodextrins (CDs) are used in chromatography analytes' retention time is decreased with an increase in concentration of CD in the mobile phase. Thus complex stability constants can be determined from the change in retention time of the ligand molecule upon complexation. Since the preceding approach implies extensive and time-consuming HPLC experiments, the goal of this research was to investigate the possibility of using in silico prediction tools instead. Quantitative structure-retention relationship (QSRR) model previously developed to explain the retention behavior of risperidone, olanzapine and their structurally related impurities in β-CD modified HPLC system was applied to predict retention factor under different chromatographic conditions within the examined domains. Predicted retention factors were further used for calculation of stability constants and important thermodynamic parameters, namely standard Gibbs free energy, standard molar enthalpy and entropy, contributing to inclusion phenomenon. Unexpected prolonged retention with an increase in β-CD concentration was observed, in contrast to the employed chromatographic theory used for the calculation of the stability constants. Consequently, it led to failure in stability constants and thermodynamic parameters calculation for almost all analytes when acetonitrile content was 20% (v/v) across the investigated pH range. Moreover, ionization of investigated analytes and free stationary phase silanol groups are pH dependent, leading to minimization of secondary interactions if free silanol groups are non-ionized at pH lower than 3. In order to prove accuracy of predicted retention factors, HPLC verification experiments were performed and good agreement between predicted and experimental values was obtained, confirming the applicability of proposed in-silico tool. However, the obtained results opened some novel questions and revealed that chromatographic method is not overall applicable in calculation of stability constants and thermodynamic parameters indicating the complexity of β-CD modified systems.

Topics: Acetonitriles; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Entropy; Models, Theoretical; Thermodynamics

The aim of this study was to develop the first CE-based method enabling separation of 20 structurally similar coumarin derivatives. To facilitate method optimization a series of three consequent Doehlert experimental designs with the response surface methodology was employed, using number of peaks and the adjusted time of analysis as the selected responses. Initially, three variables were examined: buffer pH, ionic strength and temperature (No. 1 Doehlert design). The optimal conditions provided only partial separation, on that account, several buffer additives were examined at the next step: organic cosolvents and cyclodextrin (No. 2 Doehlert design). The optimal cyclodextrin type was also selected experimentally. The most promising results were obtained for the buffers fortified with methanol, acetonitrile and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin. Since these additives may potentially affect acid-base equilibrium and ionization state of analytes, the third Doehlert design (No. 3) was used to reconcile concentration of these additives with optimal pH. Ultimately, the total separation of all 20 compounds was achieved using the borate buffer at basic pH 9.5 in the presence of 10mM cyclodextrin, 9% (v/v) acetonitrile and 36% (v/v) methanol. Identity of all compounds was confirmed using the in-lab build UV-VIS spectra library. The developed method succeeded in identification of coumarin derivatives in three real samples. It demonstrates a huge resolving power of CE assisted by addition of cyclodextrins and organic cosolvents. Our unique optimization approach, based on the three Doehlert designs, seems to be prospective for future applications of this technique.

Topics: Acetonitriles; Animals; beta-Cyclodextrins; Chamomile; Coumarins; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Methanol; Osmolar Concentration; Plant Extracts; Poisons; Rats; Research Design; Temperature

This finding described the electrochemical detection of tadalafil based on CM-β-cyclodextrin and SH-β-cyclodextrin functionalized Au@SiC nanohybrids film. The tadalafil electrochemical signal could be dramatically amplified by introducing 40% of acetonitrile in buffer medium and further enhanced by the host-guest molecular recognition capacity of β-cyclodextrin. Uniform and monodispersed ~5.0 nm Au NPs were anchored on the SiC-NH2 surface via a chemical reduction process by using polyethylene glycol and sodium citrate as dispersant and stabilizing agent. CM-β-CD was covalently bound on Au@SiC by combining the amine group of SiC-NH2 with the carboxyl group of CM-β-CD with the aid of EDC/NHS coupling agent. SH-β-CD could tightly attach to the surface of Au@SiC by the strong coordinating capability between Au and thiol. Differential pulse voltammetry was successfully used to quantify tadalafil within the concentration range of 0.01-100 µM under optimal conditions with a detection limit (S/N = 3) of 2.5 nM. In addition, the β-CD-Au@SiC nanohybrid electrochemical sensor showed high selectivity to two other erectile dysfunction drugs sildenafil and vardenafil. The proposed electrochemical sensing platform was successfully used to determine tadalafil in raw materials, herbal sexual health products, and spiked human serum samples.

Topics: Acetonitriles; beta-Cyclodextrins; Carbolines; Carbon Compounds, Inorganic; Electrochemical Techniques; Gold; Humans; Limit of Detection; Metal Nanoparticles; Phosphodiesterase 5 Inhibitors; Plants, Medicinal; Silicon Compounds; Tadalafil

A novel microextraction technique combining magnetic solid-phase microextraction (MSPME) with ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) to determine four fungicides is presented in this work for the first time. The main factors affecting the extraction efficiency were optimized by the one-factor-at-a-time approach and the impacts of these factors were studied by an orthogonal design. Without tedious clean-up procedure, analytes were extracted from the sample to the adsorbent and organic solvent and then desorbed in acetonitrile prior to chromatographic analysis. Under the optimum conditions, good linearity and high enrichment factors were obtained for all analytes, with correlation coefficients ranging from 0.9998 to 1.0000 and enrichment factors ranging 135 and 159 folds. The recoveries for proposed approach were between 98% and 115%, the limits of detection were between 0.02 and 0.04 μg L(-1) and the RSDs changed from 2.96 to 4.16. The method was successfully applied in the analysis of four fungicides (azoxystrobin, chlorothalonil, cyprodinil and trifloxystrobin) in environmental water samples. The recoveries for the real water samples ranged between 81% and 109%. The procedure proved to be a time-saving, environmentally friendly, and efficient analytical technique.

Topics: Acetates; Acetonitriles; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Fungicides, Industrial; Imines; Ionic Liquids; Liquid Phase Microextraction; Magnesium Compounds; Magnetic Phenomena; Methacrylates; Nitriles; Pyrimidines; Silicon Compounds; Solid Phase Microextraction; Solvents; Strobilurins; Water Pollutants, Chemical

Submicron, non-porous, chiral silica stationary phase has been prepared by the immobilization of functionalized β-CD derivatives to isocyanate-modified silica via chemical reaction and applied to the pressurized capillary electrochromatography (pCEC) enantio-separation of various chiral compounds. The submicron, non-porous, cyclodextrin-based chiral stationary phases (sub_μm-CSP2) exhibited excellent chiral recognition of a wide range of analytes including clenbuterol hydrochloride, mexiletine hydrochloride, chlorpheniramine maleate, esmolol hydrochloride, and metoprolol tartrate. The synthesized submicron particles were regularly spherical and uniformly non-porous with an average diameter of around 800 nm and a mean pore size of less than 2 nm. The synthesized chiral stationary phase was packed into 10 cm × 100 μm id capillary columns. The sub_μm-CSP2 column used in the pCEC system showed better separation of the racemates and at a higher rate compared to those used in the capillary liquid chromatography mode (cLC) system. The sub_μm-CSP2 possessed high mechanical strength, high stereoselectivity, and long lifespan, demonstrating rapid enantio-separation and good resolution of samples. The column provided an efficiency of up to 170,000 plates/m for n-propylbenzene.

Topics: Acetates; Acetonitriles; beta-Cyclodextrins; Capillary Electrochromatography; Chromatography, Reverse-Phase; Nanoparticles; Porosity; Silicon Dioxide; Stereoisomerism

Zearalenone (ZEA) is a widespread xenoestrogenic mycotoxin produced by several Fusarium species. ZEA can cause reproductive disorders in farm animals and hyperoestrogenic syndromes in humans; therefore, development of more sensitive analytical methods (to quantify the mycotoxin) as well as strategies for prevention of its toxic impacts is highly important. In this study, the interactions of ZEA with native and chemically modified cyclodextrins (CDs) were investigated using fluorescence spectroscopy. Furthermore, in vitro experiments on liver cells were also performed to test the potential effect of CDs on toxin uptake. Our results demonstrate that ZEA forms stable complexes with CDs (logK values are approximately 3.7-4.7) resulting in the considerable elevation of its fluorescence signal. In addition, some of the CDs show ability to inhibit the cellular uptake of ZEA, suggesting their potential suitability to develop new CD-based preventive/detoxification strategies against ZEA in the future.

Topics: Acetonitriles; beta-Cyclodextrins; Cyclodextrins; Fluorescence; Hep G2 Cells; Humans; Methanol; Spectrometry, Fluorescence; Zearalenone

A simple, rapid and sensitive chiral capillary zone electrophoresis coupled with acetonitrile-field-amplified sample stacking method was developed that allows the simultaneous enantioselective separation of the mirtazapine, N-demethylmirtazapine, 8-hydroxymirtazapine and mirtazapine-N-oxide. The separation was achieved on an uncoated 40.2 cm×75 μM fused silica capillary with an applied voltage of 16 kV. The electrophoretic analyses were carried out in 6.25 mM borate-25 mM phosphate solution at pH 2.8 containing 5.5 mg/mL carboxymethyl-β-cyclodextrin. The detection wavelength was 200 nm. Under these optimized conditions, satisfactory chiral separations of four pair enantiomers were achieved in less than 7 min in vitro. After one step clean-up liquid-liquid extraction using 96-well format, sample was introduced capillary zone electrophoresis with acetonitrile-field-amplified sample stacking to enhance the sensitivity of enantiomers. The method was validated with respect to specificity, linearity, lower limit of quantitation, accuracy, precision, extraction recovery and stability. The lower limit of quantification was 0.5 ng/mL with linear response over the 0.5-50 ng/mL concentration range for each mirtazapine, N-demethylmirtazapine and 8-hydroxymirtazapine enantiomer. The developed and validated method has been successfully applied to the enantioselective pharmacokinetic studies in 12 healthy volunteers after oral administration of rac- mirtazapine.

Topics: Acetonitriles; Administration, Oral; Antidepressive Agents, Tricyclic; beta-Cyclodextrins; Biotransformation; Buffers; Chemical Fractionation; Cyclic N-Oxides; Electrophoresis, Capillary; Humans; Limit of Detection; Male; Mianserin; Mirtazapine; Reproducibility of Results; Stereoisomerism

The illicit drug market of psychoactive substances for human abuse is continuously expanding and developing. Besides already known substance classes like cathinones, amphetamines or synthetic cannabinoids, further derivatives such as benzofurys, thiophenes, and structural analogues of methylphenidate entered the global market recently. As many of these new compounds contain a stereogenic centre it is supposed that their isomers may differ in their pharmacological effects as it is the case with amphetamines or several chiral active pharmaceutical ingredients, for instance. In the course of this study, a method for the chiral separation of a set of 16 recreational drugs by CE was developed. The aim was to separate the analytes into their enantiomers at equal conditions within short time. Sulfobutylether β-cyclodextrin served as chiral selector in an aqueous ammonium acetate solution containing ACN. For method optimization, methedrone and ethylphenidate were used as model compounds to find the appropriate concentration of chiral selector. Moreover, the influence of the pH value on enantioseparation was tested. Fourteen or 16 mM sulfobutylether β-cyclodextrin, 50 mM ammonium acetate solution (pH 4.5) with 10% ACN were found to be optimal for enantioseparation of seven benzofurys, four cathinones, two diphenidines, ethylphenidate, methiopropamine, and thiothinone. Most of them were baseline resolved at migration times below 25 min.

Topics: Acetonitriles; Benzofurans; beta-Cyclodextrins; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Illicit Drugs; Methylphenidate; Propylamines; Psychotropic Drugs; Reproducibility of Results; Stereoisomerism; Substance Abuse Detection

A sensitive on-line DPPH-CE-DAD method was developed and validated for both screening and determining the concentration of seven antioxidants of Reduning injection. The pH and concentrations of buffer solution, SDS, β-CD and organic modifier were studied for the detection of DPPH and seven antioxidants. By on-line mixing DPPH and sample solution, a DPPH-CE method for testing the antioxidant activity of the complex matrix was successfully established and used to screen the antioxidant components of Reduning injection. Then, antioxidant components including caffeic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid were quantified by the newly established CE-DAD method. Finally, the total antioxidant activity and the multiple active components were selected as markers to evaluate the quality of Reduning injection. The results demonstrated that the on-line DPPH-CE-DAD method was reagent-saving, rapid and feasible for on-line simultaneous determination of total pharmacological activity and contents of multi-components samples. It was also a powerful method for evaluating the quality control and mechanism of action of TCM injection.

Topics: Acetonitriles; Antioxidants; beta-Cyclodextrins; Biphenyl Compounds; Calibration; Drugs, Chinese Herbal; Electricity; Electronics; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Inhibitory Concentration 50; Injections; Limit of Detection; Online Systems; Picrates; Reference Standards; Temperature; Time Factors

A novel approach for the simulation of host-guest systems by systematically scanning the host molecule's orientations within the guest cavity is presented along with a thermodynamic strategy for determining preferential binding modes and corresponding optimal interaction energies between host and guest molecules. By way of example, the elution order of hexabromocyclododecane stereoisomers from high performance liquid chromatography separation on a permethylated β-cyclcodextrin stationary phase has been computed using classical molecular dynamics simulations with the explicit solvents water and acetonitrile. Comparison of estimated with experimental separation data reveals remarkable squared coefficients of correlation with R(2) = 0.87 and a very high correlation R(LOO2) = 0.72 using the leave-one-out cross-validation method and water as solvent. In particular, the approach presented shapes up as very robust in terms of the evaluated time range under consideration, reflecting well thermodynamic equilibria. These and further observations correlating with experimental results suggest the suitability of the underlying force fields and our multi-mode approach for the estimation of relative binding affinities for host-guest systems with unknown binding modes.

Topics: Acetonitriles; Algorithms; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Hydrocarbons, Brominated; Molecular Conformation; Molecular Dynamics Simulation; Monte Carlo Method; Solvents; Stereoisomerism; Surface Properties; Thermodynamics; Water

By combining a novel chiral amino-acid surfactant containing an acryloyl amide tail, a carbamate linker, and a leucine headgroup of different chain lengths with a conventional cross-linker and a polymerization technique, a new "one-pot" synthesis for the generation of amino-acid based polymeric monolith is realized. The method promises to open up the discovery of an amino-acid based polymeric monolith for chiral separations in capillary electrochromatography (CEC). The possibility of enhanced chemoselectivity for simultaneous separation of ephedrine and pseudoephedrine containing multiple chiral centers and the potential use of this amino-acid surfactant bound column for CEC and CEC coupled to mass spectrometric detection are demonstrated.

Topics: Acetonitriles; Amides; Amino Acids; beta-Cyclodextrins; Capillary Electrochromatography; Carbamates; Ephedrine; Ethylamines; Polymers; Pseudoephedrine; Reproducibility of Results; Stereoisomerism; Surface-Active Agents

The inclusion complexation behavior of salbutamol, sotalol and atenolol drugs with β-cyclodextrin (β-CD) were investigated by UV-visible, fluorometry, time resolved fluorescence, FT-IR, (1)H NMR, SEM and PM3 methods. The above drugs gave a single emission maximum in water where as dual emission in β-CD. In β-CD solutions the shorter wavelength fluorescence intensity was regularly decreased and longer wavelength fluorescence intensity increased. Addition of β-CD to aqueous solutions of drugs resulted into excimer emission. The excimer emission is concluded to be due to a 1:2 inclusion complex between β-CD and drug. Nanosecond time-resolved studies indicated that all drugs exhibited biexponential decay in solvents and triexponential decay in CD. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.

Topics: Absorption; Acetonitriles; Albuterol; Atenolol; beta-Cyclodextrins; Electrons; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Conformation; Nanostructures; Protons; Solvents; Sotalol; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Thermodynamics; Time Factors; Water

New stationary phases for hydrophilic interaction liquid chromatography (HILIC) were synthesized by covalently attaching native cyclofructan 6 (CF6) to silica gel. The chromatographic characteristics of the new stationary phases were evaluated and compared to three different types of commercial HILIC columns. The CF6 columns produced considerably different retention and selectivity patterns for various classes of polar analytes, including nucleic acid compounds, xanthines, β-blockers, salicylic acid and its derivatives, and maltooligosaccharides. Univariate optimization approaches were examined including organic modifier (acetonitrile) contents and buffer pH and salt concentration. The thermodynamic characteristic of the CF6 stationary phase was investigated by considering the column temperature effect on retention and utilizing van't Hoff plots. CF6 based stationary phases appear to have exceptionally broad applicability for HILIC mode separations.

Topics: Acetonitriles; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Fructans; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Organic Chemicals; Sodium Chloride; Thermodynamics

A rapid, sensitive, specific and selective LC-MS/MS method for the determination of zerumbone (ZER) in human plasma using 2,4-diamino-6-(4-methoxyphenyl)-1,3,5-triazine (DMTZ) as an internal standard (IS) has been developed and validated. ZER was chromatographed on C8 column using a mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.25 ml min(-1) . Quantitation was achieved using ESI+ interface, employing multiple reaction monitoring (MRM) mode at m/z 219 > 81 and 218 > 134 for ZER and IS, respectively. The calibration standards were linear over a range of 5-3000 ng ml(-1) (r(2)=0.9994) with an LLOQ of 5 ng ml(-1) (RSD %; 11.4% and bias%; 9.5%). Intra- and inter-day precision of ZER assay ranged from 0.18 to 3.56% with accuracy (bias) that varied between -5.09 and 4.3%, demonstrating good precision and accuracy. Recoveries of ZER and the IS from human plasma were above 85%. The developed method was validated for the determination of ZER in rat plasma. Linearity, stability of ZER and the ME on rat plasma were discussed. The applicability of the developed method was demonstrated by measuring ZER in rat plasma samples following intravenous and intraperitoneal administration of ZER prepared in hydroxypropyl-β-cyclodextrin (HPβCD) and sodium carboxymethyl cellulose (CMC), respectively, in 20 mg kg(-1) and this study indicated a clear significant difference (p<0.05) in pharmacokinetic parameters of ZER in ZER/HPβCD complex compared with ZER in CMC preparation.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Acetonitriles; Analysis of Variance; Animals; beta-Cyclodextrins; Carboxymethylcellulose Sodium; Chromatography, Liquid; Drug Stability; Humans; Least-Squares Analysis; Male; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity; Sesquiterpenes; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

Four novel ILs functionalized β-cyclodextrins (β-CDs) were prepared by treating 6-tosyl-β-cyclodextrin with 1,2-dimethylimidazole or 1-amino-1,2,3-triazole, and bonded to silica gel to obtain chiral stationary phases (CSPs) to be used in high-performance liquid chromatography (HPLC). The separation performances of these CSPs were examined with 16 chiral aromatic alcohol derivatives and 2 racemic drugs in acetonitrile-based polar-organic mobile phase. Excellent enantioseparations were achieved for most of the analytes. The highest value of resolution factor calculated is 6.868. Comparison of the performance of 8a, 8b, 8c and 8d suggests that the positively charged imidazole group provides electrostatic interactions probably through strong H-bonding with the analytes, whereas the cationic triazole, which forms a weaker ion pair with its counter ion, is more capable of participating in ion-pairing interactions with acidic analytes. However, for compounds 12 and 13, which have larger molecular volumes than the other analytes, the interactions between analytes and both cationic imidazole and its counter ion of the selectors play an important role in the chiral resolution. Moreover, the high resolutions were found to depend on the properties of the cations and anions on the selectors in combination with the chiral recognition sites on the rim of the CD. The ionic strength in mobile phase affects the relative interactions between analytes and the chiral selector as well as between analytes and solvents.

Topics: Acetonitriles; Alcohols; beta-Cyclodextrins; Chromatography, High Pressure Liquid; Hydrocarbons, Aromatic; Imidazoles; Ionic Liquids; Osmolar Concentration; Pharmaceutical Preparations; Silica Gel; Solvents; Stereoisomerism; Triazoles

The photochemically induced fluorescence (PIF) spectral properties of alpha-cypermethrin in organic solvents (hexane, dichloromethane, acetonitrile, ethanol) and in cyclodextrin aqueous solutions (beta-CD and 2-hydroxypropyl-beta-CD, 2-HP-beta-CD) were investigated. The photolysis kinetics of alpha-cypermethrin were evaluated in the various media. The PIF signal was found to be significantly enhanced in the CD media relative to the organic solvents. The stoichiometry and the formation constants of the alpha-cypermethrin inclusion complexes formed with the CDs were determined. The analytical performances of the PIF method were improved in the presence of HP-beta-CD relative to the other media, and a CD-enhanced PIF analytical method was developed. The limits of detection and limits of quantification ranged, respectively, between 6 and 98 ng/mL and between 24 and 343 ng/mL, depending on the medium. Application to the analysis of tap water and Senegal natural water samples collected close to agricultural areas and spiked with alpha-cypermethrin yielded satisfactory recoveries going from about 77% to 98%. An interference study of foreign species, including pesticides and inorganic ions likely to be present in natural waters, was also carried out.

Topics: Acetonitriles; beta-Cyclodextrins; Ethanol; Fluorescence; Fresh Water; Hexanes; Kinetics; Methylene Chloride; Photochemical Processes; Photolysis; Pyrethrins; Solvents; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Time Factors

Chagas disease is a serious health problem for Latin America. Nitrofurazone (NF) and Hidroxymethylnitrofurazone (NFOH) are active against Trypanosoma cruzi. The effect of beta-cyclodextrin (beta-CD) and dimethyl-beta-cyclodextrin (DM-beta-CD) complexation on the UV absorption and retention time of nitrofurazone (NF) and its hydroxymethylated analog (NFOH) were studied in solution. The retention behavior was analyzed on a reversed phase C18 column and the mobile phase used was acetonitrile-water (20/80 v/v), in which cyclodextrins (beta-CD or DM-beta-CD) were incorporated as a mobile phase additive. The decrease in the retention times of NF (or NFOH) with increasing concentration of HP-beta-CD enables the determination of the complex stability constants by HPLC. A phase-solubility study was performed, according to the method reported by Higuchi and Connors, to evaluate the changes of NF/NFOH in the complexation state, and the diagrams obtained suggested that it forms complexes with a stoichiometry of 1:1. This is an important study for the characterization of potential formulations to be used as therapeutic options for the treatment of Chagas disease.

Topics: Acetonitriles; beta-Cyclodextrins; Chemistry, Pharmaceutical; Chromatography, High Pressure Liquid; Drug Interactions; Drug Stability; Excipients; Molecular Structure; Nitrofurazone; Solubility; Solutions; Temperature; Water

In this paper, a poly(dimethylsiloxane) (PDMS) microchip with electrochemical (EC) detection was developed for rapid separation and detection of morphine and codeine. It was found that morphine and codeine were well separated within 140 s in phosphate buffer solution (PBS) (pH 6.6, 40 mM)-beta-cyclodextrin (beta-CD) (20 mM)-acetonitrile (30%, v/v). The detection limit was 0.2 microM for morphine and 1 microM for codeine. The protocol was successfully applied to monitoring the amount of morphine and codeine in human urine. Compared with the conventional methods, the presented method had many advantages such as lower instrument cost, less reagent consumption and shorter analysis time.

Topics: Acetonitriles; beta-Cyclodextrins; Buffers; Chromatography, High Pressure Liquid; Codeine; Dimethylpolysiloxanes; Electrochemistry; Electrophoresis; Humans; Hydrogen-Ion Concentration; Indicators and Reagents; Microcomputers; Morphine; Narcotics; Reproducibility of Results; Silicones; Spectrophotometry, Ultraviolet

In this work, the formation of the inclusion complex of bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane, abbreviated as BPCH) with beta-cyclodextrin (beta-CD) has been studied, 1:1 inclusion complex can be obtained, the formation constant of the beta-CD/BPCH complex is 5.94x10(3)M(-1). The photodegradation behavior of BPCH was investigated under monochromatic UV irradiation (lambda=254 nm). The photodegradation rate constant of BPCH in aqueous solutions with beta-CD showed a 9.0-fold increase, and simultaneously the mineralization of BPCH can be enhanced by beta-CD. The influence factors on photodegradation of BPCH were also studied and described in details, such as concentration of beta-CD, initial concentration of BPCH, organic solvent and pH. The photodegradation of BPCH in the presence of beta-CD includes the direct photolysis and the photooxidation of BPCH during the photochemical process. Some predominant photodegradation products are 4-(2,4,5-trihydroxy-phenyl)-4-(4-hydroxyphenyl) butanoic acid, 5,5-bis(4-hydroxyphenyl)pentanoic acid, meta-hydroxylated BPCH, ortho-hydroxylated BPCH and 4-(1-(4-hydroxyphenyl)pentyl)phenol respectively. The enhancement of photodegradation of BPCH mainly results from moderate inclusion depth of BPCH molecule in the beta-CD cavity. This kind of inclusion structure allows BPCH molecule sufficient proximity to secondary hydroxyl groups of the beta-CD cavity, and these hydroxyl groups could be activated and converted to hydroxyl radicals under UV irradiation, which can enhance the photooxidation of BPCH.

Topics: Acetonitriles; Benzhydryl Compounds; beta-Cyclodextrins; Chromatography, Liquid; Cyclohexanes; Endocrine Disruptors; Hydrogen-Ion Concentration; Kinetics; Mass Spectrometry; Photolysis; Solvents; Spectrometry, Fluorescence; Ultraviolet Rays

We synthesised and used new type of quaternary ammonium salt [S-(-)-2-hydroxymethyl-1,1-dimethylpyrrolidinium tetrafluoroborate] as effective additive to acidic background electrolytes. We used this quaternary ammonium salt as effective agent for capillary zone electrophoresis separation of model mixture of five tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, desipramine and clomipramine) as model analytes. We observed that addition of S-(-)-2-hydroxymethyl-1,1-dimethylpyrrolidinium tetrafluoroborate ([HMDP](+) [BF(4)](-)) to acidic background electrolytes leads to suppression of magnitude of electroosmotic flow (EOF) and gradually change the direction of the EOF. Baseline separation of five TAs was achieved by using of 91.1 mmol L(-1) (20 gL(-1)) of [HMDP](+) [BF(4)](-) in 25 mmol L(-1) sodium phosphate pH 2.5, where electroosmotic mobility was -11.3 x 10(-9) m(2) V(-1) s(-1). We achieved baseline separation of five TAs with using of [HMDP](+) [BF(4)](-) as water solution too. We observed that [HMDP](+) [BF(4)](-) can be used as buffer additive, which offers relatively smaller anodic electroosmotic flow instead of cationic surfactants that are mostly used for genarating of anodic electroosmotic flow in capillary electrophoresis.

Topics: Acetonitriles; Antidepressive Agents, Tricyclic; beta-Cyclodextrins; Borates; Electrolytes; Electrophoresis, Capillary; Methanol; Osmosis; Pyrrolidines

In the present study the solubility of beta-cyclodextrin and 2-hydroxypropyl-beta-cyclodextrin at sub-zero and elevated temperatures (-10 and +30 degrees C) for a given composition of methanol/water and acetonitrile/water binary mixtures (Xs = 0.16) was studied. Moreover, the freezing temperature profiles of acetonitrile-based chromatographic mobile phases were measured, and the obtained results were compared with data available in the literature. Furthermore, the effect of the macrocycles concentration on the liquid-phase freezing points was determined. The low solubility of native beta-cyclodextrin in a methanol/water mixture at sub-zero temperature as well as the non-linear behavior of acetonitrile/water mixtures that were observed concerning the freezing point profile are discussed from a practical point of view.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Acetonitriles; beta-Cyclodextrins; Chromatography, Liquid; Methanol; Phase Transition; Reproducibility of Results; Solubility; Solvents; Temperature; Transition Temperature; Water

Enantiomers of (+/-) 5-[2 (R,S)-{[2-(o-ethoxyphenoxy) ethyl] amino} propyl]-2-methoxy-benzenesulfonamide (tamsulosin, drug frequently used in the treatment of prostate diseases) were separated by capillary electrophoresis (CE). An acidic background electrolyte (BGE) with sulfated-beta-cyclodextrin (S-beta-CD) was used to create a chiral separation environment. Baseline separation of the isomers was achieved during 5 min using cathodic electro-osmotic flow (EOF) (countercurrent mode). The quantification limits were 5.3 x 10(-6) moll(-1) for R-isomer and 5.7 x 10(-6) moll(-1) for S-isomer. The R.S.D. values of peak area were 0.54% for R-isomer and 0.75% for S-isomer. The results achieved enable determination of 0.5% of optical impurity.

Topics: Acetic Acid; Acetonitriles; Adrenergic alpha-Antagonists; beta-Cyclodextrins; Calibration; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Electrolytes; Electrophoresis; Electrophoresis, Capillary; Furans; Models, Chemical; Osmosis; Reproducibility of Results; Stereoisomerism; Sulfonamides; Sulfur; Tamsulosin; Time Factors

Two simple interfaces were designed and realized, enabling on-line coupling of microfluidics reactor chips to a nanoflow electrospray ionization (NESI) time-of-flight (TOF) mass spectrometer (MS). The interfaces are based on two different approaches: a monolithically integrated design, in which ionization is assisted by on-chip gas nebulization, and a modular approach implying the use of commercially available Picospray tips. Using reserpine as a reference compound in a 1ratio1 mixture of acetonitrile and water revealed that both interfaces provide a remarkably stable mass spectrometric signal (standard deviations lower than 8% and 1% for the monolithic and modular approaches, respectively). Glass microreactors, containing mixing zones, were fabricated and coupled to the modular interface with perfluoroelastomer Nanoport fluidics connectors, providing a tool to study chemical reactions on-line. Investigation of the mixing dynamics showed that complete on-chip reagents mixing is achieved within a few tens of milliseconds. Metal-ligand interactions of Zn-porphyrin with pyridine (2), 4-ethylpyridine (3), 4-phenylpyridine (4), N-methylimidazole (5), and N-butylimidazole (6) in acetonitrile as well as host-guest complexations of beta-cyclodextrin (7) with N-(1-adamantyl)acetamide (8) or 4-tert-butylacetanilide (9) in water were studied by mass spectrometry using the modular NESI-chip interface. From on-chip dilution-based mass spectrometric titrations of Zn-porphyrin 1 with pyridine (2) or 4-phenylpyridine (4) in acetonitrile Ka-values of 4.6 +/- 0.4 x 10(3) M(-1) and 6.5 +/- 1.2 x 10(3) M(-1), respectively, were calculated. The Ka-values are about four times larger than those obtained with UV/vis spectroscopy in solution, probably due to a higher ionization efficiency of complexed compared to uncomplexed Zn-porphyrin. For the complexation of N-(1-adamantyl)acetamide (8) with beta-cyclodextrin (7), a Ka-value of 3.6 +/- 0.3 x 10(4) M(-1) was obtained, which is in good agreement with that determined by microcalorimetry.

Topics: Acetanilides; Acetonitriles; Amantadine; beta-Cyclodextrins; Calorimetry; Electrophoresis, Capillary; Electrophoresis, Microchip; Gases; Imidazoles; Ions; Kinetics; Ligands; Mass Spectrometry; Metals; Microfluidic Analytical Techniques; Microscopy, Fluorescence; Models, Chemical; Nanotechnology; Porphyrins; Protein Array Analysis; Pyridines; Reserpine; Software; Spectrometry, Mass, Electrospray Ionization; Time Factors; Water; Zinc

The resolution of clenbuterol hydrochloride enantiomers was achieved by thin-layer chromatography on silica gel GF254 plates impregnated w ith beta-cyclodextrin. The effect of stereoselective auxiliary (acetonitrile and alcohol) was investigated. Resolution of clenbuterol hydrochloride enantiomers could be attained by using alcohols of butanol, 2-butanol or tert-butanol together with acetonitrile as developing solvent. The optimal conditions of resolution were determined as follows: a plate prepared with 15.00 g silica gel GF254 impregnated with 1.00 g beta-cyclodextrin, acetonitrile-2-butanol (20:80, v/v) as developing solvent and developed at room temperature. Under these conditions, Rf of the two isomers of clenbuterol hydrochloride enantiomers were 0.34 and 0.72 respectively. The resolution was 4.09 with baseline separation and the spots in chromatogram were almost of the same size.

Topics: Acetonitriles; Alcohols; beta-Cyclodextrins; Chromatography, Thin Layer; Clenbuterol; Silicon Dioxide; Stereoisomerism

A variety of compounds containing amines (i.e., amino acids, amino alcohols, etc.) were chemically derivatized with a variety of electrophilic tagging reagents to elucidate the chiral recognition sites on a teicoplanin-bonded chiral stationary phase (CSP) and on R-naphthylethylcarbamate-beta-cyclodextrin (RN-beta-CD)-bonded CSP. Solutes were separated under optimum chromatographic conditions on teicoplanin and RN-beta-CD CSPs for comparison using an acetonitrile-based mobile phase. It was noted that the size of the analyte or tagging reagent exerted a greater influence on compounds separated on teicoplanin than on RN-beta-CD when using the polar organic mode. This suggests that chiral recognition on teicoplanin CSP is more sensitive to size and indicates that the hydrophobic pocket of teicoplanin plays a significant role in chiral recognition in this mode. However, the type of functional groups had a greater impact than the size of analyte on separations obtained from RN-beta-CD phase in the polar-organic mode. Specifically, the pi-pi interaction was enhanced by derivatizing the aromatic ring of the tagging reagent with electron-withdrawing groups and thus altered the resolution substantially. For both phases, chiral recognition is most pronounced when the stereogenic center of the analyte is near the tagging moiety and surrounded by functional groups (e.g., carboxylic, etc.) which are favorable for hydrogen bonding.

Topics: Acetonitriles; Amino Acids; beta-Cyclodextrins; Chromatography; Chromatography, High Pressure Liquid; Chromatography, Liquid; Cyclodextrins; Models, Chemical; Stereoisomerism; Teicoplanin; Time Factors; Water

A variety of alpha-amino acids are enantioresolved for the first time on naphthylethylcarbamate-beta-cyclodextrin bonded phases (i.e., SN- and RN-beta-CD) using the acetonitrile-based mobile phase after their pre-column derivatization with phenyl isothiocyanate in alkaline medium. The resolution is better obtained on RN-beta-CD phase and fails to reproduce if the amino acid is N-benzoylated or N-carbobenzyloxylated under the same chromatographic conditions. The enhanced resolution is believed to be due to the re-location of the hydrogen receptor site from sulfur to nitrogen on the isothiocyanyl fragment of derivatizing reagent, which in turn changes the enantioselectivity. Also, the sulfur atom is larger in size and subject to steric hindrance more significantly in comparison with oxygen. The carboxyl group of amino acid is essential toward a satisfactory resolution. The position of the amino group on the backbone affects the resolution as well. Finally, the resolution is either not observed or unsatisfactory in the reversed- or normal phase mode for most of the amino acids examined in this study.

Topics: Acetonitriles; Amino Acids; beta-Cyclodextrins; Carbamates; Chromatography, High Pressure Liquid; Isothiocyanates; Molecular Structure; Peptides; Stereoisomerism; Thiocyanates

The chiral separation of a substituted imidazole p38 MAP kinase inhibitor and its intermediates was investigated using capillary electrophoresis (CE) with various sulfated cyclodextrins. After initial screens, a single CE chiral method with a randomly sulfated beta-CD was selected for the evaluation of chiral purity for all three compounds. Operational parameters, such as the concentration of the chiral selectors, background electrolyte (or mobile phase) pH, organic modifiers, and temperature were varied in order to achieve an optimized method. The optimal method was validated in terms of linearity, sensitivity, precision, ruggedness, and specificity.

Topics: Acetonitriles; beta-Cyclodextrins; Electrophoresis, Capillary; Enzyme Inhibitors; Hydrogen-Ion Concentration; Imidazoles; Indicators and Reagents; Molecular Structure; p38 Mitogen-Activated Protein Kinases; Solutions; Stereoisomerism; Temperature

The retention behaviour of the three positional isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was investigated on a porous graphitic carbon (PGC) column. The influence of the mobile phase composition (nature and concentration of organic and electronic modifiers) was studied as well as the effect of column temperature. These hydrophilic and anionic analytes were highly retained on the PGC stationary phase compared to octadecyl bonded phases. The retention is mainly governed by a reversed-phase mechanism with electronic interaction playing a secondary role. An increase in solute retention and efficiency with temperature was observed. Successful isocratic separation with satisfactory baseline resolution of the three isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was achieved at 75 degrees C on a Hypercarb column by using ammonium acetate as electronic modifier in water-acetonitrile (83:17). The chromatographic methodology developed can be easily used for relative quantification of each isomer within a mixture and can be applied for semi-preparative purification of each one. The evaporative light scattering detector allows the detection of these non UV-visible absorbing molecules.

Topics: Acetonitriles; beta-Cyclodextrins; Buffers; Carbon; Chromatography, Liquid; Isomerism; Molecular Structure; Salts; Temperature

A facile method of enantioresolving a variety of alpha-amino acids and peptides on naphthylethylcarbamate-beta-cyclodextrin bonded phases (i.e., SN- and RN-beta-CDs) under the elution of acetonitrile-based mobile phase makes use of 2,4-dinitrofluorobenzene (DNFB) as the tagging reagent, which undergoes nucleophilic substitution by the free amino group in alkaline medium to give a N-2,4-dinitrophenyl (DNP) derivative. The resolution is better obtained on RN-beta-CD phase and fails to reproduce on the intact beta-cyclodextrin bonded phase under the same chromatographic conditions, which strongly suggests that the observed resolution should be due to the interaction of analyte with naphthylethylcarbamate moiety, not with the residual secondary hydroxyl groups on the beta-cyclodextrin.

Topics: Acetonitriles; Amino Acids; beta-Cyclodextrins; Carbamates; Chromatography, High Pressure Liquid; Dinitrobenzenes; Peptides; Stereoisomerism

Association constants, Kc, were derived from the electrophoretic mobilities of the anionic solutes (seven benzoates with hydroxy or chloro substituents) by capillary zone electrophoresis in different solvent systems, consisting of binary mixtures of water with up to 20% (v/v) methanol or acetonitrile, respectively. The association constants expectedly are found to decrease with increasing organic solvent concentration. The effect of organic solvents on the Kc of the benzoates with beta-cyclodextrin was analyzed applying the concept of the transfer activity coefficient (or the medium effect). This concept enables the evaluation of the significance of the contributions of the individual species involved in the complexation equilibrium in the different solvents: the benzoate ion, beta-cyclodextrin, and the anionic benzoate-beta-cyclodextrin complex. The medium effect on benzoate was calculated from the change in acidity constant of benzoic acid in the different mixed solvents and the corresponding transfer activity coefficients of the proton and the molecular acid. The transfer activity coefficients for beta-cyclodextrin results from its solubility at saturation in the different solvents. In this way, an estimation of the standard free energy of transfer, deltaG(t)0, of each species involved in the complexation equilibrium was possible for the transfer from water into the respective mixed solvent. It was found that the organic solvents do not significantly affect deltaG(t)0 for the benzoate anion. However, the organic solvents play a different role concerning the stabilization of beta-cyclodextrin and the complex anion: whereas the addition of acetonitrile has nearly no influence on deltaG(t)0 of the anionic complex, the reduction in Kc is caused by the enhanced stabilization of beta-cyclodextrin (reflected by its better solubility). Addition of methanol, on the other hand, lowers the solubility of beta-cyclodextrin, thus giving positive values for deltaG(t)0. Thus, the overall effect on Kc in methanolic solutions must be related to the pronounced destabilization of the benzoate-beta-cyclodextrin complex.

Topics: Acetonitriles; Anions; Benzoates; beta-Cyclodextrins; Cyclodextrins; Electrophoresis, Capillary; Methanol; Solvents; Thermodynamics

The supramolecular interaction of curcumin and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied and discussed based on the variations of pK(a), absorption intensity, and infrared spectrograms. The results show that beta-CD reacts with curcumin to form a 2:1 host-guest complex with an apparent formation constant of 5.53 x 10(5) mol(-2) x L2. Based on the enhancement of the absorbance of curcumin produced through complex formation, a spectrophotometric method for the determination of curcumin in bulk aqueous solution in the presence of beta-CD was developed. The linear relationship between the absorbance and curcumin concentration was obtained in the range of 0-15 microg/mL, with a correlation coefficient (r) of 0.9991. The detection limit was 0.076 microg/mL. The proposed method was used to determine the curcumin in curry and mustard with satisfactory results.

Topics: Acetonitriles; beta-Cyclodextrins; Curcumin; Cyclodextrins; Drug Interactions; Hydrogen-Ion Concentration; Solutions; Solvents; Spectrophotometry; Spectrophotometry, Infrared; Thermodynamics

As part of our on-going study of the analysis of anti-human immunodeficiency virus (HIV) nucleosides, a capillary electrochromatography (CEC) method has been developed for the concurrent analysis of nucleoside HIV reverse transcriptase inhibitors (NRTIs) in a pool of endogenous nucleosides. Up to now, beta-cyclodextrin-bonded silica stationary phases have mainly been dedicated to the separation of enantiomers; however, these polysaccharides can be also be used in achiral way. This work aims at showing how CEC performed on a beta-cyclodextrin-bonded silica stationary phase can be used to concurrently resolve zidovudine (AZT), lamivudine (3TC), didanosine (ddA) and its administrated form (ddI), stavudine (d4T) and hivid (ddC) in a mixture of adenosine (A), cytidine (C), guanosine (G), thymidine (T) and uridine (U). The influence of several parameters (pH buffer, ionic strength, acetonitrile content, temperature and voltage) on both the retention times and the retention factors has been investigated using the short-end injection technique to achieve baseline separation in a short-time analysis before quantitation. Moreover, the retention factors of the charged solutes in short-end injection-CEC were calculated using theoretically derived equations, allowing for the actual voltage drop in the packed section of the semipacked CEC capillary.

Topics: Acetonitriles; Anti-HIV Agents; beta-Cyclodextrins; Buffers; Chromatography, High Pressure Liquid; Cyclodextrins; Electrophoresis, Capillary; Humans; Hydrogen-Ion Concentration; Models, Theoretical; Nucleosides; Osmolar Concentration; Reproducibility of Results; Reverse Transcriptase Inhibitors; Sensitivity and Specificity

Our aim was to establish suitable conditions for the chiral separation of 12 1,3,4-thia- and 1,3,4-selenadiazine derivatives; some of them were identified in screening tests as potential antituberculotics. To overcome possible problems with the water insolubility of most analytes, we profited by the advantages of non-aqueous capillary electrophoresis. Methanol, formamide, and a mixture of formamide with acetonitrile (1:2, v/v) were used as separation media. Hydroxyethyl-, hydroxypropyl-, and methyl-beta-cyclodextrin were applied as chiral selectors in concentrations of 200 mM. Besides the effect of these different electrophoretic media and selectors, we also investigated the consequences of using different electrolytes (25 mM ammonium acetate/1 M acetic acid and 25 mM citric acid/12.5 mM TRIS). Distinct differences of the separation factors in the different separation media were observed. Depending on structure characteristics of the analytes, we established clear classifications to these cyclodextrins (CD), which were most appropriate for the separation of the enantiomers of the particular analytes.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Acetates; Acetic Acid; Acetonitriles; beta-Cyclodextrins; Citric Acid; Cyclodextrins; Electrophoresis, Capillary; Formamides; Methanol; Organometallic Compounds; Organoselenium Compounds; Stereoisomerism; Thiadiazines; Time Factors; Tromethamine

Native beta- and gamma-cyclodextrin bound to silica (ChiraDex-beta and ChiraDex-gamma) were packed into capillaries and used for enantiomer separation by capillary electrochromatography (CEC) under aqueous and nonaqueous conditions. Negatively charged analytes (dansyl-amino acids) were resolved into their enantiomers by nonaqueous CEC (NA-CEC). The addition of a small amount of water to the nonaqueous mobile phase enhanced the enantioselectivity but increased the elution time. The choice of the background electrolyte (BGE) determined the direction of the electroosmotic flow (EOF). With 2-(N-morpholino) ethanesulfonic acid (MES) or triethylammonium acetate (TEAA) as BGE an inverse EOF (anodic EOF) was observed while with phosphate a cathodic EOF was found. The apparent pH (pH*), the concentration of the BGE, and the nature of the mobile phase strongly influenced the elution time, the theoretical plate number and the chiral separation factor of racemic analytes.

Topics: Acetonitriles; Amino Acids; beta-Cyclodextrins; Buffers; Cyclodextrins; Dansyl Compounds; Electrolytes; Electrophoresis, Capillary; gamma-Cyclodextrins; Hydrogen-Ion Concentration; Methanol; Osmolar Concentration; Solvents; Stereoisomerism; Water

Micellar electrokinetic chromatography (MEKC) was used for the chiral separation of uncharged analytes (C- and N-protected amino acids). Sodium dodecyl sulfate (SDS) was the micelle forming agent, and different cyclodextrin (CD) derivatives were added as chiral selectors. Suitable conditions for the enantioseparation were found by variation of the separation conditions. The influence of addition of organic solvents like acetonitrile or methanol, and other chiral additives (camphor-10-sulfonic acid, malic acid) was examined. The addition of an organic modifier resulted in different effects on micelle formation, and thereby on the separation. The used chiral additives did not improve the selectivity. Furthermore, dependence of the electroosmotic flow (EOF), and the capacity factors on the concentration of CDs was investigated. Increasing the CD concentration, both the EOF to a smaller extent as well as the capacity factors decrease. Nevertheless, the enantioseparation is improved with a CD-concentration up to 30 mM. Higher CD-concentrations reduce the separation of the analytes.

Topics: Acetonitriles; Amino Acids; beta-Cyclodextrins; Chromatography, Micellar Electrokinetic Capillary; Cyclodextrins; Esters; gamma-Cyclodextrins; Indicators and Reagents; Sensitivity and Specificity; Sodium Dodecyl Sulfate; Solvents; Stereoisomerism

Enantiomeric separation of 21 amino acids derivatized with fluoresceine isothiocyanate isomer I (FITC) has been studied by micellar electrokinetic chromatography using beta- and gamma-cyclodextrin (CD) as chiral selectors. Chiral resolution of 21 FITC derivatives of amino acids was achieved with both beta- and gamma-CD in 100 mM borate buffer (pH 9.5) containing 30 mM sodium dodecyl sulfate (SDS). The effects of CD concentration, SDS concentration and organic modifiers' concentration as well as capillary length were investigated. Chiral recognition capability of beta- and gamma-CD was compared. Gamma-CD was found to be a better chiral selector than beta-CD in terms of chiral resolution capability for FITC-amino acids.

Topics: 2-Propanol; Acetonitriles; Amino Acids; beta-Cyclodextrins; Chromatography; Cyclodextrins; Fluorescein-5-isothiocyanate; gamma-Cyclodextrins; Isomerism; Sodium Dodecyl Sulfate; Time Factors

A cyclodextrin-modified capillary electrophoretic method has been developed for the analysis of eleven common resin acids using a pH 4.5, 20 mM sodium acetate buffer containing 10% acetonitrile, 20 mM methyl-beta-cyclodextrin (MECD) and 30 mM sulfobutylether-beta-cyclodextrin (SBCD) as buffer modifiers. At pH below their pKa (< 5.7-6.4) the resin acids were virtually unionized and insoluble; however, they formed water-soluble inclusion complexes with MECD (20 mM) or SBCD (30 mM) even at pH 4.5. The analytes were separated in 25 min and, with the exception of two pairs, 12- or 14-chlorodehydroabietic/12,14-dichlorodehydroabietic acid and dehydroabietic/palustric acid, the remaining resin acids were baseline-separated. Analysis time was significantly shortened (< 12 min) at pH 9.25 using 30 mM SBCD and 20 mM MECD in 20 mM sodium borate. Resin acids were baseline-separated with the exception of two pairs, pimaric/sandaracopimaric acid and 12- or 14-chlorodehydroabietic/abietic acid. The addition of 7.5% methanol to the running buffer resolved the abietic acid peak. Both HPLC and micellar capillary electrokinetic chromatography using 20 mM deoxycholic acid, 10% acetonitrile in 20 mM sodium borate, pH 9.25, failed to resolve the resin acids. The simple capillary electrophoretic method developed would be useful for the rapid separation and characterization of several important resin acids in pulp mill effluents and other contaminated samples.

Topics: Acetonitriles; beta-Cyclodextrins; Cyclodextrins; Electrophoresis, Capillary; Hydrogen-Ion Concentration; Resins, Plant; Solubility; Time Factors