摘要:

A hypothesis of the mechanism of the retention of one (stationary) phase of a two-phase liquid system in a rotating coil column has been proposed. The balance of forces of different nature acting on the stationary phase retained in the coil column has been considered. The basic equation of the retention process stationarity has been derived. Theoretical dependencies of retention factor on rotational speed for hydrophobic systems and experimental data are in good agreement.

ISSN:1082-6076    

DOI:10.1080/10826079608014576

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

High-speed countercurrent chromatography is a recently developed separation method that has been remarkably improved in both separating efficiency and separation time. In this paper, this advanced countercurrent chromatographic method was applied to the separation of lanthanides. In combination with the measurement of the partition coefficient of lanthanides, a suitable solvent system was chosen. The separation of a mixture containing the trivalent lanthanides La, Ce, Pr and Nd was performed with 0.15M P507(2-ethylhexyl-2-ethylhexyl hydrogen phosphate) chloroform : hydrochloric acid, pH=2.93, (1:1, V/V) solvent system. The resolution of adjacent bands was enhanced with increasing rotational speed, and was reduced with increasing flow rate of the mobile phase. This enhancement resulted from an increasing number of theoretical plates. Mutual separation of adjacent lanthanides was accomplished with adequate resolution.

ISSN:1082-6076    

DOI:10.1080/10826079608014577

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

High performance liquid chromatographic methods were established for the determination of parishin, parishins B and C in three kinds of the traditional Chinese medicinal prescriptions, including Gastrodiae Rhizoma: Shuen-Feng-Iun-Chi-San, Ban-Shia-Bai-Ju-Tian-Ma-Tang and Tsan-Siang-Tian-Ma-Tang. The samples were analyzed with an Inertsil ODS-2 reversed phase column by gradient elution with varied 0.1% (v/v) phosphoric acid-acetonitrile as mobile phases and detected at UV 222 nm. Ethoxybenzamide was used as an internal standard. Regression equations were derived showing linear relationships (correlation coefficients: 0.9976–0.9999) between the peak area ratios of each marker (parishin, parishins B and C) to ethoxybenzamide and concentration. The recoveries of parishin, parishins B and C from the Chinese medicinal preparations were 102.0–104.1%, 102.9–105.0% and 103.2–104.0%, respectively.

ISSN:1082-6076    

DOI:10.1080/10826079608014578

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A simple, specific and sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of l-(5-(3,4-dimetoxyphenyl)-pyrazol-3-yl-oxypropyl)-3-[n-methyl-n-[2-(3,4-dimethoxyphenyl)ethyl]amino] propane hydrochloride (KC11346) and two of its metabolites (KC12795, KC12816) in dog plasma. KC11346, KC12795, KC12816 and KC11294 (internal standard) are extracted from dog plasma by methyl t-butyl ether (MTBE) following an alkalization of plasma. MTBE is removed from the extract with a gentle stream of nitrogen at 40°C and reconstituted in 200 μL of mobile phase. Separation of the reconstituted extract is achieved by HPLC on a Zorbax SB-CN column with a mobile phase composed of (56:44) 50 mM sodium acetate/acetonitrile. The analytes were detected by fluorescence detection with a Corion UG-11 cut off filter and an excitation wavelength of 265 nm. The mean retention times of KC12816, KC12795, KC11346, and the internal standard were 4.8, 8.1, 9.0, and 14.4 minutes, respectively. The assay is linear over the concentration range 3 to 350 ng/mL. The analysis of pooled quality control samples (8. 30, and 300 ng/mL) demonstrates excellent precision with relative standard deviations (RSD) (n = 18) ⩽ 7.5% for all three compounds. The method is accurate with all intraday (n = 6) and overall mean values ⩽ 15.7% from theoretical at all control concentrations for all compounds.

ISSN:1082-6076    

DOI:10.1080/10826079608014579

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A reverse phase high performance liquid chromatographic method has been developed for the simultaneous determination of six pyrethrin esters, piperonyl butoxide (PBO), dipropyl pyridine-2,5-dicarboxylate (MGK 326), and endo- and exo-N-octyl bicycloheptene dicarboximide (MGK 264) in pet shampoo formulations. A C8Octyl reverse phase column and different compositions of acetonitrile, methanol and water as mobile phases were used. The eluent was monitored with UV absorption at 220, 230, 240 and 225 nm. Internal standard calculations using peak area was used to calculate each active ingredient peak. Interfering inert ingredients were separated from all active ingredients using this method. This simple and reliable technique has an advantage over GC because of the thermal degradation of pyrethrins, and over normal phase high performance liquid chromatography, since it requires no further sample clean-up.

ISSN:1082-6076    

DOI:10.1080/10826079608014580

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A liquid chromatography method for analysis of amoxicillin was examined in a collaborative study involving 11 laboratories. The method comprised an isocratic part, which is used in the assay. The isocratic part is similar to the assay method for amoxicillin of the United States Pharmacopeia 23. When the isocratic part is combined with gradient elution, the method is suitable for purity control. Five samples of amoxicillin (trihydrate and sodium salt) with varying purity were analysed.

ISSN:1082-6076    

DOI:10.1080/10826079608014581

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effects of acetate (Ac) concentration on the separation of lanthanides from hydronium ion (H3O+) in capillary zone electrophoresis is investigated. The effects of sample acidity and buffers on the H3O+peak have been studied. A mixture of 14 rare earth metals, along with H3O+, can be baseline separated in less than nine minutes by use of a ternary buffer system [sodium acetate (NaAc) /α-hydroxyisobutyric acid (HIBA) / UV CAT-1]. In contrast, replacing NaAc by equal molar sodium chloride (NaCl) in the buffer decreases the electroosmotic flow without enhancing selectivity and resolution of lanthanides. All of these results suggest that the higher mobility H3O+ion elutes slower than would be predicted. The late appearance of H3O+at pH=4.4 is attributed to the weak acid-base equilibria of HIBA and HAc in the buffers as H3O+migrates through the capillary. The improved separation of metal ions from H3O+by the addition of sodium acetate is also due to the equilibrium of the weak acid (HAc).

ISSN:1082-6076    

DOI:10.1080/10826079608014582

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The separation of proteins of fetal calf serum using a MECC method was developed. The influence of pH, sample dilution, nature and concentration of buffer, concentration of surfactant and other conditions affecting the separation were optimized. The usefulness of the addition of two replaceable polymers: hydroxypropylmethylcellulose and dextran to the buffer was investigated. Although their addition had little influence on the separation, an improvement of the resolution of some group of peaks were observed. A 25 mM borate/25 mM phosphate buffer, pH=8.5. with 50 mM SDS allowed to separate the proteins of fetal calf serum, rat serum and healthy and abnormal human serum with good resolution and short analysis time. The potential of this method in clinical diagnosis is demonstrated. Using standard proteins, an assignment of some peaks in human serum was proposed. Then, the method was applied to the evaluation of a biomimetic drug carrier. The interaction of orosomucoid-coated nanoparticles with serum proteins was evidenced and compared with the one of uncoated nanoparticles. The method allowed to establish a kinetic of desorption of pre-adsorbed orosomucoid by competition with serum proteins.

ISSN:1082-6076    

DOI:10.1080/10826079608014583

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

High performance liquid chromatography procedures have been developed for the assay of ondansetron-selected medications in 0.9% sodium chloride injection USP. The separation and quantitation of each mixture were performed on either an underivatized silica column or a bonded phase column at ambient temperature using either a methanol or acetonitrile-phosphate buffer mobile phase in the 4–5.4 pH ranges with detection set at 254, 233 or 210 nm. The separations were usually achieved within 20 min. Linearity, limit of detection, retention and tailing factors, resolution, accuracy and precision were calculated for each mixture.

ISSN:1082-6076    

DOI:10.1080/10826079608014584

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Some Boraginaceous roots contain red colored pigments, alkannin and shikonin, which are used in therapy as well as in food and textile industry. For the quantitative analysis of these enantiomeric naphthaquinone derivatives, a cellolose carbamate based chiral column (Chiralcel OD) on HPLC was used by using hexane/2-propanol (90:10) as mobile system. The method was applied to determine the alkannin and shikonin contents of the roots of eighteen Boraginaceous plants and results were also compared with those of the LiChrospher RP-18 column.

ISSN:1082-6076    

DOI:10.1080/10826079608014585

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor