An analytical CE method was developed for the enantiomeric purity determination of fluvastatin enantiomers. Fluvastatin enantiomers were separated on an uncoated fused silica with 100 mM-borate solution containing 30 mg/mL of (2-hydroxypropyl)-beta-cyclodextrin (HP-beta-CD) as running buffer and fenoprofen as an internal standard. The linearity was observed within a 400-700 microg/mL concentration range (r(2)>or=0.995) for both fluvastatin enantiomers. The repeatability expressed as coefficient of variation (CV) of the method were 0.96 and 0.92% for (+)-3R, 5S and (-)-3S, 5R-fluvastatin, respectively. The limit of detection and quantification for both fluvastatin enantiomers were 1.5 microg/mL and 2.5 microg/mL, respectively.
The economic and effective method for preparation of R-(-)-ibuprofen by diastereomer crystallization was developed. R-(-)-ibuprofen was resolved from racemic ibuprofen by forming R-(-)-ibuprofen-R-(+)-alpha-methylbenzylamine diastereomeric salt with R-(+)-alpha(-methylbenzylamine and crystallization. The purity of R-(-)-ibuprofen-R-(+)-alpha-methylbenzylamine diastereomeric salt was tested and confirmed using HPLC and 1H-NMR method. The pure diastereomeric salt collected from repeated recrystallization was further fractionated by liquid-liquid extraction to the pure enantiomer without racemization. R-(-)-ibuprofen was recovered producing overall yield of 2.4% with the purity more than 99.97%.
Two methods for the chiral purity determination of bevantolol were developed, namely capillary electrophoresis (CE) using carboxymethyl-beta-cyclodextrin (CM-beta-CD) as a chiral selector and high-performance liquid chromatography (HPLC) using a chiral stationary phase. In the HPLC method, the separation of bevantolol enantiomers was performed on a Chiralpak AD-H column by isocratic elution with n-hexane-ethanol-diethylamine (10:90:0.1, v/v/v) as mobile phase. In the CE method, bevantolol enantiomers were separated on an uncoated fused silica capillary with 50 mM amonium phosphate dibasic adjusted to a pH 6.5 with phosphoric acid containing 15 mM CM-beta-CD as running buffer. Validation data such as linearity, recovery, detection limit, and precision of the two methods are presented. The detection limits of S-(-)-bevantolol were 0.1% and 0.05% for CE and HPLC method, respectively and R-(+)-bevantolol were 0.15% and 0.05% for CE and HPLC method, respectively. There was generally good agreement between the HPLC and CE results.
Pure enantiomers are of large interest for several industries. This study was aimed to establish a method for separation of etodolac enantiomers by preferential crystallization after a conglomerate formation of its derivatives. S-(+)-etodolac and R-(-)-etodolac enantiomers were both prepared by classical resolution via crystallization of diastereoisomeric salt with (-)-brucine and (-)-cinchonidine. Enantiomeric purity of etodolac was determined by HPLC method using Chiralcel OD-H column. The pure diastereomeric salt collected from repeated recrystallization was further fractionated by liquid-liquid extraction to pure enantiomers. Etodolac enantiomers were recovered with overall yield more than 20% and the purities were over 99.9%.
Furfural, an important compound applied in many areas, could be synthesized from biomass which is inexpensive and abundant. In this study, magnetic sulfonated graphene oxide (Fe3O4/SGO) was synthesized and used as a catalyst for producing furfural from sugarcane bagasse by co-precipitation method. The characteristics of the catalyst material were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, Raman spectroscopy, Brunauer-Emmett-Teller specific surface area, and the vibrating-sample magnetometer. The results showed that Fe3O4/SGO was successfully synthesized with a specific surface area of 121.8 m 2 /g. The empirical data indicated that under the condition of 190 o C, 90 mins of reaction, the furfural synthesis efficiency could reach 14.07 %. According to the results, Fe3O4/SGO is highly promising for furfural production from biomass.
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