Separation of Aminoglycosides by Normal- and Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC - The normal-phase (NP) and reversed-phase (RP) thin-layer chromatographic separations of aminoglycosides (streptomycin, kanamycin,...     

Separation of Statin-Type Antihyperlipidemic Drugs by Reversed-Phase TLC

JPC – Journal of Planar Chromatography – Modern TLC -     

Analysis of Non-Selective Calcium-Channel Blockers by Reversed-Phase TLC

The selectivity of TLC separation of non-selective calcium-channel blockers prenylamine, lidoflazine, bepridil, and fendiline has been investigated silanized silica gel RP8 and RP18 plates. Optimization of retention and selectivity for these compounds was achieved by altering the pH and the concentration of organic modifier (methanol, ethanol, tetrahydrofuran, acetonitrile) in the aqueous mobile phases. The substances were separated in horizontal chambers and the drugs were detected by videoscanning and illumination of the plates at λ = 254 nm. On RP8 plates the best separation was achieved with 50% acetonitrile in pH 2.06 phosphate buffer as mobile phase. On RP18 the best separation was achieved with 50% ethanol in pH 2.06 phosphate buffer.

     

Reversed-Phase Chromatographic Retention Behavior of Some Fibrate-Type Antihyperlipidemic Drugs

JPC – Journal of Planar Chromatography – Modern TLC - Relationships between RM values and mobile phase composition have been examined for six fibrate-type drugs–bezafibrate,...     

Normal- and Reversed-Phase Thin-Layer Chromatography of Selected Calixarenes and Pyrene

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of calix[4]arene, 4-tert-butyl-calix[4]arene tribenzoate, 4-tert-butylcalix[5]arene, and pyrene have...     

Normal- and Reversed-Phase Thin-Layer Chromatography of Seven Oral Antidiabetic Agents

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of seven oral antidiabetic drugs -chlorpropamide, tolbutamide, glibenclamide, metformin, pioglitazone,...     

Normal- and Reversed-Phase Behaviour of 16,17-Secoestrone Derivatives on Cyanopropyl-Bonded Silica Gel

The retention behaviour of a number of 16,17-secoestrone derivatives has been studied by LC and HPTLC on a polar cyanopropyl-bonded stationary phase using non-aqueous and aqueous-organic mobile phases. The retention behaviour has been discussed in terms of nature of the solute, eluent and stationary phase. The correlation between retention constants of 16,17-secoestrone derivatives obtained from reversed-phases and commercially available ACD log P software (Advanced Chemistry, Toronto, Canada) has also been examined.

     

Normal- and Reversed-Phase Behaviour of 16,17-Secoestrone Derivatives on Cyanopropyl-Bonded Silica Gel

The retention behaviour of a number of 16,17-secoestrone derivatives has been studied by LC and HPTLC on a polar cyanopropyl-bonded stationary phase using non-aqueous and aqueous-organic mobile phases. The retention behaviour has been discussed in terms of nature of the solute, eluent and stationary phase. The correlation between retention constants of 16,17-secoestrone derivatives obtained from reversed-phases and commercially available ACD log P software (Advanced Chemistry, Toronto, Canada) has also been examined.     

Retention Behavior of New Oral Antidiabetic Drugs in Reversed-Phase Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - The thin-layer chromatographic behavior of three of the newest oral antidiabetic agents, pioglitazone, rosiglitazone, and...     

Normal- and Reversed-Phase Thin-Layer Chromatography of Three Structurally Related Organophosphorus Pesticides of Forensic Importance

JPC – Journal of Planar Chromatography – Modern TLC - Recently, considerable numbers of poisoning cases have been reported owing to the ingestion of three structurally related...     

Normal and Reversed-Phase TLC Determination of Rosmarinic and Valerenic Acids

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic properties of valerenic and rosmarinic acids have been studied by normal- and reversed-phase TLC with eight...     

PICO－TAG反相色谱法测定鸡蛋中氨基酸含量

采用ＰＩＣＯ－ＴＡＧ反相色谱法测定了氨基酸，方法的相对标准偏差为０．７５％，平均回收率为９７．１２％。对鸡蛋样品进行了测定，发现不同产地不同皮色鸡蛋中氨基酸含量无显著差异，样品测定相对标准偏差为１．６７％。结果表明测定方法快速、灵敏、准确、重现性好。     

Reversed-Phase Thin-Layer Chromatographic Behavior of Some s-Triazine Derivatives

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of four groups of s-triazine derivatives (14 compounds) has been studied by TLC on silica gel...     

Effect of Ionic Liquids as Mobile-Phase Additives on Chromatographic Parameters of Neuroleptic Drugs in Reversed-Phase High-Performance Liquid Chromatography

Abstract

Ionogenic basic compounds belonging to phenothiazine derivatives were analyzed in the reversed-phase system and were modified with the addition of three ionic liquids: 1-ethyl-3-methyl-imidazolium hexafluorophospate (EMIM PF₆), 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMIM PF₆), and 1-butyl-3-methyl-imidazolium chloride (BMIM Cl). The effects of the concentration and the type of ionic liquid on the analytes' retention, peak symmetry, and efficiency were examined. The following trends increase analytes' retention factor and improve system efficiency: BMIM PF₆ > EMIM PF6 > BMIM Cl. With its asymmetric cation enlarged with hydrophobic substituents and a chaotropic anion, BMIM PF₆ appeared to be the most advantageous one. The isotherm of adsorption of this reagent presents a typical Langmuir course. By the application of high-performance liquid chromatography, lipophilicity parameters were established (lnk_w, S, ? ₀) for the investigated compounds. Chromatographic systems modified with ionic liquids were compared to buffered organic–aqueous mobile phase and eluent containing chaotropic salt additive.     

Comparison of Normal and Reversed-Phase TLC for Separation of Selected Pesticides

JPC – Journal of Planar Chromatography – Modern TLC - Fifteen urea pesticides have been separated on RP-18WF254 plates with methanol-water and mixed organic (acetonitrile-methanol, 1:1...     

反相色谱法分离氨基苯磺酸和氨基萘磺酸离子性化合物的研究

本文讨论了反相色谱分离氨基苯磺酸,氨基萘磺酸离子性化合物的可行性。所应用的实验条件为检测波长254nm,流动相为10mmol/L 磷酸二氢钠缓冲液(pH=6.98),固定相是C_(18)担体。还讨论了分子结构对保留值的影响。     

Reversed-Phase Ion-Pairing Liquid Chromatographic Separation and Fluorimetric Detection of Polyamines

Abstract

A rapid and specific reversed-phase ion-pairing high performance liquid chromatographic procedure for putrescine, spermidine and spermine is reported. The ion-pairing reagent, heptanesulfonate, was employed and o-phthalaldehyde and 2-mercaptoethanol were used for on-line post-column derivatization and subsequent fluorescence detection. Experiments were carried out to determine the effects of several variables such as pH, concentration of the aqueous buffer, counter-ion concentration, and the percentage of organic modifier in the moving phase. The minimum detection limits for the polyamines ranged from 120 pmoles for spermine to 12 pmoles for putrescine. The method includes a gradient program which provides complete separation from amino acids and specificity for the three polyamines. The procedure was applied successfully to urine and serum samples.     

Reversed-Phase High-Performance Liquid Chromatographic Determination of Artemisitene in Artemisinin

Abstract

A new, simple and selective reversed-phase HPLC assay is developed for the determination of the clinically undesirable artemisitene in the antimalarial agent artemisinin (qinghaosu). It involves the use of an internal standard (santonin) and the determination time is less than 5 minutes. Detection was accomplished using a UV detector set at 216 nm and limits were as low as 15ng for a 10μl injection. Being simple and selective this method is particularly useful for the routine analysis of artemisinin to check its purity. In addition, the method can be used for preparative scale purification of these compounds. It has been applied for the evaluation of crystalline samples of artemisinin without prior preparation.     

Supported Liquid Membrane Work-Up of Blood Plasma Samples Coupled On-Line to Liquid Chromatographic Determination of Basic Antidepressant Drugs

An automated sample pretreatment of human blood plasma for liquid chromatographic determination of three antidepressant drugs, dibenzepine; a tricyclic antidepressant (TCA), reboxetine; a selective noradrenaline reuptake inhibitor (SNRI) and fluvoxamine; a selective serotonin reuptake inhibitor (SSRI), based on supported liquid membrane (SLM) for unsurpassed sample clean-up and analyte enrichment, has been developed. The chromatograms after enrichment of plasma blank and aqueous blank are virtually indistinguishable. The entire analytical procedure revealed good linearity and low detection limits of 5, 15 and 20 ng mL^–1 for dibenzepine, reboxetine and fluvoxamine, respectively. No carry-over effects were noted. The repeatability of extraction at three concentrations in the range 40–150 ng mL^–1 for the three drugs was between ca. 3% and 7% as relative standard deviation. The reproducibility relative standard deviation during three different days (replacing the membrane each day) was not significantly higher.     

Analysis of Some Antihistamine Drugs in Normal-Phase Chromatographic Systems

JPC – Journal of Planar Chromatography – Modern TLC - The selectivity of the separation of five antihistamines has been investigated by TLC on silica gel 60 F254 and on aluminium oxide...