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C18 Analytical Column (c18 + analytical_column)
Selected AbstractsSimultaneous determination of diethylene glycol and propylene glycol in pharmaceutical products by HPLC after precolumn derivatization with p -toluenesulfonyl isocyanateJOURNAL OF SEPARATION SCIENCE, JSS, Issue 16 2007Tao Zhou Abstract A simple and reliable HPLC method was developed for the simultaneous quantitative analysis of diethylene glycol (DEG) and propylene glycol (PG) in pharmaceutical products by precolumn derivatization. The derivatization reagent p -toluenesulfonyl isocyanate (TSIC, 10 ,L, 20% in ACN v/v) was added to 100 ,L of the sample, and then 10 ,L of water was added. The resulting derivatives were separated using a C18 analytical column and a mobile phase composed of 0.01 M KH2PO4 buffer (adjusted to pH 2.5 with phosphoric acid) and ACN (47:53 v/v) at 1 mL/min and 25°C. For detection, UV light at 227 nm was used. The derivatization conditions including reaction time, temperature, and concentration of TSIC were optimized. The calibration curves were linear from 0.062 to 18.6 ,g/mL (r2 = 0.9999) and from 0.071 to 21.3 ,g/mL (r2 = 0.9999) for DEG and PG, respectively. The RSD values of intra- and interday assays were all below 4% for DEG and PG. The proposed method was then successfully applied to analyze two Armillarisin A injection samples and two spiked syrup samples. [source] Quality control of Pulsatilla koreana based on the simultaneous determination of triterpenoidal saponins by HPLC-ELSD and principal component analysisPHYTOCHEMICAL ANALYSIS, Issue 4 2010Ki Yong Lee Abstract Introduction , Pulsatilla koreana Nakai, with triterpenoidal saponins as its main pharmacological effective compounds, is known to have several biological activities, including hypoglycaemic, antitumour, cognition-enhancing, neuroprotective, cytotoxic and antiangiogenic activities. However, few analytical methods have been reported on the quality assessment of P. koreana roots. Obejective , To establish a high-performance liquid chromatography coupled with evaporative light scattering detection for the simultaneous determination of five triterpenoidal saponins, including pulsatilloside E (1), pulsatilla saponin H (2), anemoside B4 (3), hederacolchiside E (4) and cussosaponin C (5) in P. koreana. Methodology , The chromatographic separation was performed on a Shiseido CapCell PAK C18 analytical column efficiently using gradient elution with acetonitrile and water. Results , All calibration curves showed excellent linear regressions (R2 > 0.9996) within the range of tested concentrations. The intra- and inter-day variations were below 4.78% in terms of RSD. The recoveries were 94.82,102.97% with RSD of 0.27,3.92% for spiked P. koreana samples. Conclusion , The validated method was successfully used for the analysis of five saponins in P. koreana from different locations. Moreover, the different samples were clustered in accordance with contents of triterpenoidal saponins based on aglycon type by a principal component analysis. Copyright © 2010 John Wiley & Sons, Ltd. [source] Congener-specific analysis of hexabromocyclododecane by high-performance liquid chromatography/electrospray tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2003Wesley Budakowski A congener-specific method based on high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ES-MS/MS) in the negative ion mode was developed for the analysis of hexabromocyclododecane (HBCDD). On a C18 analytical column, with a methanol/water mobile phase, the , -isomer was completely resolved from the , - and , -isomers while the , - and , -isomers were sufficiently resolved at half their peak heights. The ES spray voltage strongly influenced the intensity of the ion signal. For MS, a source temperature of 500°C and a collision energy of 50,eV were found to be optimum for the [M,H], to Br, transition. Run-to-run and day-to-day (n,=,3) variability was minimal, with relative standard deviations of 2.6,4.1 and 2.4,4.4%, respectively. The limit of detection was 4,6,pg on-column. When applied to tissue samples from Lake Winnipeg fish both , - and , -isomers of HBCDD were found in low-ng/g (lipid corrected) concentrations. Copyright © 2003 John Wiley & Sons, Ltd. [source] A sensitive and specific liquid chromatography/tandem mass spectrometry method for determination of echinacoside and its pharmacokinetic application in ratsBIOMEDICAL CHROMATOGRAPHY, Issue 6 2009Hao Yang Abstract A rapid and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the determination of echinacoside in rat plasma was established and fully validated. A single step of liquid,liquid extraction with n -butanol was utilized. Chromatographic separation of the analyte and the internal standard (IS), chlorogenic acid, from the sample matrix was performed using a Capcell-MG C18 analytical column (100 2.0 mm × 5 µm), with a gradient of acetonitrile and water containing 0.1% acetic acid as the mobile phase. Detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization source operated in negative ion selected reaction monitoring mode. The method was linear in the concentration range 10,2500 ng/mL. The deviations of both intra- and inter-day precisions (RSD) were 7.1% and the assay accuracies were within 99.2,106.5%. Echinacoside proved to be stable during sample storage, preparation and analysis when an antioxidant solution was used. The method was successfully applied to a pharmacokinetic study in rats after an intragastric administration of echinacoside (100 mg/kg). With the lower limit of quantification at 10 ng/mL, this method proved to have sufficient selectivity, sensitivity and reproducibility for the pharmacokinetic study of echinacoside. Copyright © 2009 John Wiley & Sons, Ltd. [source] Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutical preparationsBIOMEDICAL CHROMATOGRAPHY, Issue 1 2007S. Torres-Cartas Abstract The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil C18 analytical column; the mobile phase was 0.04 m cetyltrimethylammonium bromide (CTAB), at pH 3, containing 5% 1-butanol, at a flow rate of 1 mL/min. The CE separation was performed in a fused-silica capillary with a 50 mm tris-(hydroxymethyl)-aminomethane buffer, pH 7, at an applied voltage of 20 kV, using barbital as internal stardard. The proposed methods are suitable for a reliable quantitation of these compounds in the commercial tablets and drops in terms of accuracy and precision and require a very simple pre-treatment of the samples. By comparing the performance characteristics and experimental details of the MLC and CE methods we conclude that CE seems to be slightly better than MLC in the determination of highly hydrophobic compounds in pharmaceuticals in terms of resolution and economy, taking into account that the limits of detection are not a handicap in pharmaceutical samples. Copyright © 2006 John Wiley & Sons, Ltd. [source] Methodology Optimization for Quantification of Total Phenolics and Individual Phenolic Acids in Sweetpotato (Ipomoea batatas L.) RootsJOURNAL OF FOOD SCIENCE, Issue 7 2007M.S. Padda ABSTRACT:, Phenolic acids are one of the several classes of naturally occurring antioxidant compounds found in sweetpotatoes. Simplified, robust, and rapid methodologies were optimized to quantify total and individual phenolic acids in sweetpotato roots. Total phenolic acid content was quantified spectrophotometrically using both Folin,Denis and Folin,Ciocalteu reagents. The Folin,Ciocalteu reagent gave an overestimation of total phenolic acids due to the absorbance of interfering compounds (that is, reducing sugars and ascorbic acid). Individual phenolic acids were quantified by high-performance liquid chromatography (HPLC) using the latest in column technology. Four reversed-phase C18 analytical columns with different properties (dimensions, particle size, particle shape, pore size, and carbon load) were compared. Three different mobile phases using isocratic conditions were also evaluated. A column (4.6 × 150 mm) packed with 5-,m spherical silica particles of pore size 110 Å combined with 14% carbon load provided the best and fast separation of individual phenolic acids (that is, chlorogenic acid, caffeic acid, and 3 isomers of dicaffeoylquinic acid) with a total analysis time of less than 7 min. Among the 3 mobile phases tested, a mobile phase consisting of 1% (v/v) formic acid aqueous solution: acetonitrile: 2-propanol, pH 2.5 (70:22:8, v/v/v) gave adequate separation. Among the solvents tested, aqueous mixtures (80:20, solvent:water) of methanol and ethanol provided higher phenolic acid extraction efficiency than the aqueous mixture of acetone. [source] | ||||||||||