摘要:

Commercial D,L-kynurenine was resolved by high-speed countercurrent chromatography using a cross-axis coil planet centrifuge. The separation was performed with an aqueous-aqueous polymer phase system composed of 10% (w/w) polyethylene glycol 8000 and 5% (w/w) dibasic sodium phosphate containing 6% (w/w) bovine serum albumin as a chiral selector. The lower phosphate-rich mobile phase eluted the L-enantiomer first followed by the D-enantiomer. The peak resolution was 0.94 for 2.5 mg of the sample. The separation was completed within 3.5 h.

ISSN:1082-6076    

DOI:10.1080/10826079808001942

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

High-speed countercurrent chromatography was successfully applied to the isolation of colistin-A and colistin-B from a commercial colistin preparation. As the first step. TLC and HPLC analysis conditions for the colistin components were established. Using these techniques, a two-phase solvent system composed of n-butanol-0.04M aqueous trifluoroacetic acid (TFA) (1:1) was selected for high-speed CCC, where the concentration of TFA was the major factor in controlling the partition coefficients of the colistin components. Yields of colistin-A and colistin-B were 9 mg each from 20 mg of the commercial sample, and the purity of each component was over 90%. Fast atom bombardment (FAB) mass spectrometry was utilized to confirm the nature of the isolated components.

ISSN:1082-6076    

DOI:10.1080/10826079808001943

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A mixture of taxol and cephalomannine was subjected to recycling countercurrent chromatography (CCC) which allows the use of the same column for repetitive separation of the peak fractions to improve the peak resolution. When the total amount of 50 mg of the two components was recycled twice, peak resolution (Rs) increased from 0.7 to 1.27. The results also showed that Rsvalue increases according to the formula: Rs-n= n1/2Rs-1where n is the number of CCC runs, and Rs-1and Rs-n, peak resolutions after the first and the nth run, respectively.

ISSN:1082-6076    

DOI:10.1080/10826079808001944

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

High-speed countercurrent chromatography (CCC) was applied to the separation of strychnine and brucine from crude extract ofStrychnos nux-vomica L. using a two-phase solvent system composed of chloroform/0.07 M sodium phosphate, 0.04 M citric buffer (pH 5.08) (1:1, v/v). Fractionated components were identified with authentic pure compounds on TLC and also analyzed by HPLC, IR and FTMS. The results showed that from 40 g of the seed powder, 48.2 mg of strychnine was purified at 99.9% purity (83.3% recovery) while 18.1 mg of brucine fraction was obtained after rechromatographed by preparative TLC improving the purity to 91.2%.

ISSN:1082-6076    

DOI:10.1080/10826079808001945

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Anti-HIV lignans were purified from extract ofLarrea tridentataby high-speed countercurrent chromatography (CCC) using pH-zone-refining CCC. When a column filled with methyl t-butyl ether, containing trifluoroacetic acid at 25 mM, was eluted with aqueous NaOH, 10 to 20 g of the crude extract was separated into NDGA (nordihydroguaiaretic acid) and its monomethyl esters rectangular peaks associated with their specific pH (pH zones). The method was also successfidly applied to synthetic lignans, resulting in resolution of NDGA and its mono and dimethyl esters.

ISSN:1082-6076    

DOI:10.1080/10826079808001946

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A 5-g sample of commercial 4,5,6,7-tetrachlorofluorescein (TCF) was subjected to pH-zone-refining countercurrent chromatography to separate an unidentified contaminant present in all TCF batches obtained from four different suppliers. The separated contaminant (44 mg) was characterized by1H- and13C nuclear magnetic resonance spectrometry and negative ion chemical ionization mass spectrometry as a new seven-membered lactone TCF isomer with the structure 11,12,13, 14-tetrachloro-3, 14b-dihydroxy-[2]-benzoxepino- [3,4,5-kl]-xanthene-10(14bH)-one.

ISSN:1082-6076    

DOI:10.1080/10826079808001947

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A rapid, efficient separation of multigram quantities of 2- and 6-nitro-4-chloro-3-methoxybenzoic acid was achieved by pH-zone-refining CCC.

ISSN:1082-6076    

DOI:10.1080/10826079808001948

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A synthetic mixture of epigallocatechin gallate and gallocatechin gallate was separated using multiple countercurrent chromatographic instruments by connecting the separation columns in series. Peak resolution increased according to the formula Rs-n= n1/2Rs-1, where n is the number of columns connected; Rs-nand Rs-1, the peak resolution obtained from n columns and a single column, respectively. Various sample sizes and concentrations were applied to four columns connected in series. The results indicated that the sample loading capacity is increased 11 times that of the single instrument for the same peak resolution.

ISSN:1082-6076    

DOI:10.1080/10826079808001949

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

High-speed countercurrent chromatography was used for the preparative separation and purification of kaempferol, isorhamnetin, and quercetin from leaf extracts ofGinkgo biloba L. and the commercial quercetin standard with a two-phase solvent system composed of chloroform-methanol-water (4:3:2, v/v/v).

ISSN:1082-6076    

DOI:10.1080/10826079808001950

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Using high-speed countercurrent chromatography (CCC), technical chlorflurenol-methyl was successfully separated into methyl 9-hydroxy-9-fluorenecarboxylate, methyl 2-chloro-9-hydroxy-9-fluorenecarboxylate, methyl 2,7-dichloro-9-hydroxy-9-fluorenecarboxylate. This method can be used for the determination of octanol-water coefficients (Kow) for technical chlorflurenol-methyl and its separated components. The CCC can also be employed for the characterization and purification of the reaction products from synthesis of chlorflurenol-methyl.

ISSN:1082-6076    

DOI:10.1080/10826079808001951

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor