Determination Of Active Components Research Articles

Separation and determination of active components in Radix Salviae miltiorrhizae and its medicinal preparations by nonaqueous capillary electrophoresis.

A nonaqueous capillary electrophoresis (NACE) method was developed for simultaneous assay of three bioactive components (1: cryptotanshinone; 2: tanshinone IIA, and 3: tanshinone I) in Radix Salviae miltiorrhizae and in its herbal preparations for the first time. After optimization of separation conditions, a buffer of 250 mmol L(-1) ammonium acetate containing 30% acetonitrile and 1.0% acetic acid (V:V) in methanol was selected for separating the three analytes, but baseline separation of tanshinon I and tanshinone IIA was not obtained. Therefore second-order derivative electropherograms were applied for resolving overlapping peaks. Regression equations revealed good linear relationships (correlation coefficients 0.9943-0.9991) between peak heights in second-order derivative electropherograms and concentrations of the three analytes. The relative standard deviations (RSD) of the migration times and the peak height of the three constituents were in the range of 0.81 -0.88% and 0.34-1.13% (intra-day), 1.57-1.86% and 3.05-5.52% (inter-day), respectively. The recoveries of three constituents ranged from 90.2 to 108.5%. The results indicated that baseline separation of the analytes was sometimes hard to obtain and second-order derivative electropherograms were applicable for the resolving and analysis of overlapping peaks.

Simultaneous separation and determination of active components in Cordyceps sinensis and Cordyceps militarris by LC/ESI-MS

A simple and rapid isocratic LC/MS coupled with electrospray ionization (ESI) method for simultaneous separation and determination of adenine, hypoxanthine, adenosine and cordycepin in Cordyceps sinensis (Cs) and its substitutes was developed. 2-Chloroadenosine was used as internal standard for this assay. The optimum separation for these analytes was achieved using the mixture of water, methanol and formic acid (85:14:1, v/v/v) as a mobile phase and a 2.0×150 mm Shimadzu VP-ODS column. Selective ion monitoring (SIM) mode ([M+H] + at m/ z 136, 137, 268, 252 and 302) was used for quantitative analysis of above four active components. The regression equations were liner in the range of 1.4–140.0 μg ml −1 for adenine, 0.6–117.5 μg ml −1 for hypoxanthine, 0.5–128.5 μg ml −1 for adenosine and 0.5–131.5 μg ml −1 for cordycepin. The limits of quantitation (LOQ) and detection (LOD) were, respectively 1.4 and 0.5 μg ml −1 for adenine, 0.6 and 0.2 μg ml −1 for hypoxanthine, 0.5 and 0.1 μg ml −1 for adenosine and cordycepin. The recoveries of four constituents were from 93.5 to 107.0%. The nucleoside contents of various types of natural Cs and its substitutes were determined and compared with this developed method.

Determination of active components in Rhubarb and study of their hydrophobicity by micellar electrokinetic chromatography

A micellar electrokinetic chromatographic (MEKC) method has been developed for the determination of five anthraquinones and one distyrene derivative in rhubarb. The separation conditions were optimized and two kinds of rhubarb plants and rhubarb-containing medicines were analyzed. The negatively charged solutes migrated toward the anode and were retarded by their interaction with the micelle. Hydrophobicity of the solutes was studied by both MEKC with SDS and SDS-free capillary zone electrophoresis in the buffer of 15 mmol/L NaH 2PO 4+ 20 mmol/L borax and 15% ethanol (v/v). Linear correlation between log k′ and log P OW was obtained for the five anthraquinones in SDS micelle system. The capacity factor, k′, and free energy differences Δ(Δ G) derived from this method provided fundamental information on the interaction between the solutes and the micelle.

Separation and Determination of Active Components in Rhubarb by Cyclodextrin-Modified Micellar Electrokinetic Chromatography Using a Mixed Micellar System

A novel method for determination of five anthraquinone derivatives and one distyrene derivative in Rhubarb by CD-MEKC with mixed micellar system of SDS and STC was developed. The separation was optimized by adjusting buffer pH, SDS, STC, and β-CD concentrations. The six components were separated successfully in buffer solution of 20 mmol/L NaOH + H3BO3 (pH 11) containing 20 mmol/L SDS and 20 mmol/L STC with 15 mmol/L β-CD. The method was examined in terms of linearity, detection limit, precision, and recovery. Two commercial Rhubarb plants and its preparation were analyzed by the proposed method.

Application of experimental design and artificial neural networks to separation and determination of active components in traditional Chinese medicinal preparations by capillary electrophoresis

Orthogonal design has been used for optimization of the separation and determination of two active components (pair of isomers) in a traditional Chinese medicinal preparation by capillary electrophoresis. The concentration of borate and SDS, the organic modifier content and buffer pH were selected as variable parameters. Their different effects on peak resolution were studied by the design method. Optimized separation conditions were obtained and successfully applied for the first time to the separation and determination of imperatorin and isoimperatorin inYuanhu Zhiteng tablets within 7 min in a pH 8 buffer system: 25 mM borate, 15 mM SDS and 5% acetonitrile, detection at 214 nm. In addition, application of an artificial neural network with “4-7-1” structure to the prediction of peak resolution of the two active components given by uniform design was also examined and the predicted results were in good agreement with experimental values.

Determination of Active Components in Rhubarb by Cyclodextrin-modified Capillary Zone Electrophoresis

A cyclodextrin-modified capillary zone electrophoresis was developed for the determination of four bioactive components in Rhubarb. Effects of pH, b-CD concentration and organic modifier content on the migration and separation of the components were studied. The four components were separated in the running buffer of 50 mmol/L NaOHH3BO3 (pH 10.7) containing 10 mmol/L b-CD and 12.5% v/v ethanol. The analytical performance of the method was tested with respect to linearity response, precision and recovery. The determination of two commercial Rhubarb samples under the optimized conditions showed a satisfactory result.

Determination of active component in silymarin by RP-LC and LC/MS.

Silybin, isosilybin, silydianin and silycristin in silymarin were separated and quantitatively determined by RP-HPLC. Two diastereoisomers of silybin and isosilybin were respectively separated by RP-HPLC and confirmed by LC/MS. Chromatographic condition consisted of column: Shim-pack VP-ODS (150 x 4.6mm i.d. 5 microm) and Pre-column (10 x 4.6 mm i.d. 5 microm); mobile phase: methanol and solvent mixture (water: dioxane=9:1) by gradient; flow rate: 1.5ml/min; column temp.: 40 degrees C; detector wavelength: 288 nm; The recovery of 99.66% for silycristin, 99.48% for silydianin, 100.0% for silybin and 98.72% for isosilybin was respectively obtained.

Identification and determination of active components in Angelica dahurica Benth and its medicinal preparation by capillary electrophoresis

A micellar electrokinetic capillary chromatography (MECC) method for the separation of three active components, imperatorin (IM), isoimperatorin (IO) and scopoletin (SC), in Angelica dahurica Benth and its preparation was developed. The optimum separation for these analytes was achieved using 10 mM borate, 20 mM SDS and 10%(v/v) acetonitrile, with applied voltage of 22 kV. All experiments were performed using a 50.0 cm (42.5 cm effective length)×75 μm I.D. fused-silica capillary. The linear calibration range was 12.0–800.0 μg ml −1 for IM, 10.0–850.0 μg ml −1 for IO and 3.5–600.0 μg ml −1 for SC. The recoveries of three constituents were from 91.3 to 108.7%. Also, the dissociation constant (pKa) of SC was determined by the CE method established in this paper.

Identification and determination of active components in Gastrodia elata Bl. by capillary electrophoresis

Capillary zone electrophoresis (CZE), using a 25 m M borate buffer (pH 10.0) with 10% (v/v) acetonitrile, was established for the identification and determination of five constituents – gastrodin (GA), 4-hydroxybenzyl alcohol (HA), vanillyl alcohol (VA), 4-hydroxybenzaldehyde (HD) and vanillin (VL) – in the extracts of Gastrodia elata Bl. roots. Regression equations revealed linear relationships (correlation coefficients: 0.9992–0.9999) between the peak area of each constituent (GA, HA, VA, HD and VL) and its concentration. The relative standard deviations of the migration times of five constituents ranged between 0.99 and 1.43%. The recoveries of five constituents ranged between 94.3 and 109.2%. The GA, VA and HA contents measured 6.18 mg/g (1.11% RSD), 0.71 mg/g (0.86% RSD) and 0.25 mg/g (8.56% RSD), respectively, in the sample of Gastrodia elata Bl. collected in Sichuan province. Also, the dissociation constant of GA was determined by a CE method.

Determination of active components in insecticide formulations by liquid chromatography and resolution of overlapped peaks by multivariate analysis and derivative spectrophotometry

In liquid chromatography, complex mixtures of pesticides may show peaks with a great overlap under the experimental conditions commonly used. The use of partial-least squares (PLS) regression and derivative spectrophotometry makes it possible to discriminate between the spectral bands of the overlapping chromatographic solutes, taken from peaks with co-eluting species. In this paper, a procedure for the determination of insecticides in commercial formulations by using a diode-array spectrophotometer as chromatographic detector has been devised. The procedure consists of two steps. In the (first) chromatographic step, the active component peak (corresponding to fenitrothion or permethrin) which is isolated in time is determined by conventional liquid chromatography; the appropriate conditions permit to remove also the interference from solvents in the commercial formulations. In the (second) multivariate step, partial-least squares regression is applied to the overlapped spectra of the co-eluting components (piperonyl butoxide-neopynamine or dicofol-tetradifon). This method makes it possible to analyze compounds showing appreciable overlap of their chromatographic peaks, without modification of the experimental variables used.

Use of Derivative Spectrophotometry in the Resolution of Overlapped Peaks in Liquid Chromatography and Its Application in the Analysis of Active Components in Insecticide Formulations

Abstract A procedure for the determination of active components in insecticide formulations showing overlapped peaks in liquid chromatography has been devised. The procedure is based in the use of derivative spectra of the components obtained by a diode-array spectrophotometer around the maxima signal of the chromatographic peak, and has been applied to the analysis of mixtures of piperonyl butoxide, neopynamine and fenitrothion with satisfactory results.

Determination of active components in insecticide formulations by derivative ultraviolet spectrophotometry

A rapid second-derivative ultraviolet spectrophotometric method for the resolution of mixtures of two components in commercially available insecticide formulations that cannot be resolved by conventional spectrophotometry was developed and applied to the analysis of mixtures of piperonyl butoxide with neopynamine, permethrin and fenitrothion, with satisfactory results.

Analysis of creams

The possibilities for the determination of active components in creams by acid-base titrations in non-aqueous solvents were investigated. Interference by cream-base components with the titration of weak organic bases and their halides with perchloric acid in acetic acid, and with the titration of weak acids with tetrabutylammonium hydroxide in N,N-dimethylformamide were studied. It appeared to be possible to determine alkaloid halides, salicylic acid, hexachlorophene and methyl salicylate without previous clean-up of the cream samples.