Search results for: Boric Acid - Borate Buffer, pH 8.2
#23021635 2012/09/12 To Up
Preparative enantioseparation of β-blocker drugs by counter-current chromatography using dialkyl L-tartrate as chiral selector based on borate coordination complex.
Counter-current chromatography (CCC) was applied for preparative enantioseparation of three β-blocker drugs, including propranolol, pindolol and alprenolol. The two-phase solvent system was composed of chloroform-0.05 mol L(-1) acetate buffer containing 0.10 mol L(-1) boric acid (1:1, v/v), in which 0.10 mol L(-1) di-n-hexyl L-tartrate was added in the organic phase as chiral selector. Influence factors in the enantioseparation of propranolol were investigated. The chromatographic retention mechanism based on borate coordination complex was proposed. 116 mg of racemic propranolol was completely enantioseparated using conventional high speed CCC in a single run, yielding 48 mg of (+)-propranolol with HPLC purity of 98.9% and 47 mg of (-)-propranolol with HPLC purity of 96.3%. Recovery for propranolol enantiomers from CCC fractions was in the range of 75-82%. pH-zone-refining CCC was also successfully applied in enantioseparation of propanolol and it was found that 356 mg of racemic propranolol could be completely enantioseparated. 145 mg of (+)-enantiomer with HPLC purity of 95.6% and 148 mg of (-)-enantiomer with HPLC purity of 98.2% were recovered from pH-zone-refining mode. Separation mechanism about chiral separation by pH-zone-refining CCC was discussed.Shengqiang Tong, Ye Zheng, Jizhong Yan, Yi-Xin Guan, Chunyan Wu, Wenyu Lei
1140 related Products with: Preparative enantioseparation of β-blocker drugs by counter-current chromatography using dialkyl L-tartrate as chiral selector based on borate coordination complex.
500 tests1 kit(96 Wells)100tests1 mg1 kit1 kit251 kit(96 Wells)100 assays96 assaysRelated Pathways
#11296932 // To Up
A new strategy for optimizing sensitivity, speed, and resolution in capillary electrophoretic separation of DNA.
DNA separations were performed in poly(ethylene oxide) (PEO) solutions prepared in 100 mM Tris-boric acid (TB) buffers using a capillary filled with TB buffers with concentrations up to 2.5 M, pH 10.0. The electroosmotic flow (EOF) increased with increasing the concentration of TB buffers till 1.5 M as a result of decreasing PEO adsorption on the capillary wall. At high TB concentrations (> 1.5 M), the peaks corresponding to small DNA fragments (11 and 8 base pairs) became sharper and were detected. Relative standard deviations of the EOF coefficient and the migration times of the DNA fragments were all less than 1% using a capillary filled with TB buffers at concentrations higher than 1.5 M. When separations were performed at different pH values of PEO solutions and TB buffers, better results in terms of sensitivity, speed, and resolution were generally achieved. The fluorescence intensity of the 2176 bp fragment obtained at pH values of TB buffers/PEO solutions 10.0/8.2 was 27-fold of that at pH values 8.2/8.2. The enhancement was related to effects of pH and borate on fluorescence intensity, DNA conformation, stacking, and interactions with the capillary wall. Using a capillary filled with 400 mM TB buffers, pH 10.0, the separation of DNA (pBR 322/HaeIII digest, pBR 328/Bg/I digest and pBR 328/HinfI digest) in 1.5% PEO solutions prepared in 100 mM TB buffers, pH 9.0, at 375 V/cm was accomplished in less than 18 min.W L Tseng, H T Chang
1255 related Products with: A new strategy for optimizing sensitivity, speed, and resolution in capillary electrophoretic separation of DNA.
100 μg 1 G100 μg32-50 Sample Kit1 SetRelated Pathways
#8381734 // To Up
Assessment and optimization of kinetic methods for angiotensin-converting enzyme in plasma.
In the kinetic angiotensin-converting enzyme (ACE) method, a practical and optimal buffer is 80 mmol/L borate buffer at pH 8.2 (37 degrees C). A lag phase is detected in the reaction, and a 5-min incubation of substrate and plasma is suggested before the kinetic measurement. The substrate, N-[3-(2-furyl)acryloyl]-L-phenylalanylglycylglycine (FAPGG), concentration is maximized at 1.0 mmol/L and the measurement wavelength is at 345 nm to ensure linearity of measurement. The proposed procedure uses a 1:9 plasma-to-reagent volume ratio. The linear range of the assay extends to approximately 170 U/L, representing a 25% substrate hydrolysis. The FAPGG absorptivity is determined by measuring the difference in absorbance between 1.0 mmol/L FAPGG and the product solutions. The wavelength fidelity is checked by noting the expected absorbance value of the FAPGG solution, and a 1.0-nm deviation from 345 nm alters the absorbance by 15.5%. The precision of ACE assays at approximately 60 and 100 U/L is 3.5% and 2.4% within batch and 2.9% and 2.6% between batch, respectively. The reference interval (2.5th to 97.5th percentiles) is 41-139 U/L, and there is no difference between values for men and women.J E Buttery, S Stuart
1989 related Products with: Assessment and optimization of kinetic methods for angiotensin-converting enzyme in plasma.
96 wells (1 kit)100ug100 ug100ug100 ug100ul100ug100ul96T100.00 ug100 ug100ugRelated Pathways
#3433956 // To Up
Quantitative aspects of two methods to dissolve collagen-free muscle proteins from acetone dry powders of Guelders ring sausage.
The purpose of this study was to find experimental conditions for the complete solubility of collagen-free muscle proteins (CFMP) using acetone powder of Guelders ring sausage. Preliminary experiments were carried out to choose the best procedure for preparing the acetone dry powder. Two different methods of acetone extraction of minced sausage were compared. The acetone dry mass (ADM) method using continuous extraction in a Soxhlet [2] apparatus gave better results than the acetone powder (ACP) method, which used a blender [1]. The ADM method was used for further investigations. ADM was extracted with two types of sodium dodecyl sulphate (SDS), containing solvents A and B. Solvent A contains a Tris-boric acid buffer (pH 8.2) with 1.5% (m/v) SDS and 0.05% (m/v) dithioerythreitol [3]. Solvent B is a borate-chloric acid buffer (pH 9.0) with 2.0% (m/v) SDS and 1.0% (m/v) mercapto-ethanol [2]. Both solvents showed a linear relationship between the quantities of CFMP in ADM and the dissolved CFMP. The linear relationships were found between quantities of 10.0 and 30.0 mg (solution A) and of 5.0 and 30.0 mg ADM (solution B) per ml solvent. The solubility of CFMP was better in solvent B than in solution A. Completely dissolved CFMP from ADM was only obtained in the case of 5.0 mg ADM in 1.0 ml solution B. These conditions will be used in liquid chromatography experiments, the results of which will be reported later.M A Jonker, P S van Roon, J M den Hartog
2053 related Products with: Quantitative aspects of two methods to dissolve collagen-free muscle proteins from acetone dry powders of Guelders ring sausage.
0.1 mg51 mg0.1 mg500 100Tests200 100tests1mg500 10 mg5Related Pathways
Contact Us:
Belgium
Voortstraat 49, 1910 Kampenhout BELGIUM
Tel 0032 16 58 90 45 Fax 0032 16 50 90 45
[email protected]
France
9, rue Lagrange, 75005 Paris
Tel 01 43 25 01 50 Fax 01 43 25 01 60
[email protected]
Germany
GENTAUR GmbH
Marienbongard 20
52062 Aachen Deutschland
Tel 0241 40 08 90 86 Fax 0241 55 91 05 36
[email protected]
United Kingdom
GENTAUR Ltd.
Howard Frank Turnberry House
1404-1410 High Road
Whetstone London N20 9BH
Tel 020 3393 8531 Fax 020 8445 9411
[email protected]
Also in
Luxembourg +35220880274
Schweiz Züri +41435006251
Danmark +4569918806
Österreich +43720880899
Česká republika Praha +420246019719
Ireland Dublin +35316526556
Norge Oslo +4721031366
Finland Helsset +358942419041
Sverige Stockholm +46852503438
Ελλάς Αθήνα +302111768494
Magyarország Budapest +3619980547
Poland
GENTAUR Poland Sp. z o.o.
ul. Grunwaldzka 88/A m.2
81-771 Sopot, Poland
Tel 058 710 33 44
Fax 058 710 33 48
[email protected]
skype gentaurpoland
Nederland
GENTAUR Nederland BV
Kuiper 1
5521 DG Eersel Nederland
Tel 0208-080893 Fax 0497-517897
[email protected]
Italy
GENTAUR SRL
IVA IT03841300167
Piazza Giacomo Matteotti, 6, 24122 Bergamo
Tel 02 36 00 65 93 Fax 02 36 00 65 94
[email protected]
Spain
GENTAUR Spain
Tel 0911876558
[email protected]
Bulgaria
GENTAUR Bulgaria
53 Iskar Str. 1191 Kokalyane, Sofia
Sofia 1000
Tel 0035924682280
Fax 0035929830072
[email protected]