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A sensitive and simple HPLC method was developed for the simultaneous quantification of berberine and lysergol in rat plasma. The chromatographic separation was achieved on a C18 column using isocratic elution with methanol–acetonitrile–0.1% ortho‐phosphoric acid (25:20:55, v/v/v), pH adjusted to 6.5 with triethylamine and detected at a UV wavelength of 230 nm. The extraction of the berberine and lysergol from the rat plasma with methylene chloride resulted in their high recoveries (82.62 and 90.17%). HPLC calibration curves for both berberine and lysergol based on the extracts from the rat plasma were linear over a broad concentration range of 50–1000 ng/mL. The limit of quantification was 50 ng/mL. Intra‐ and inter‐day precisions were <15% and accuracy was 87.12–92.55% for berberine and 87.01–92.26% for lysergol. Stability studies showed that berberine and lysergol were stable in rat plasma for short‐ and long‐term period for sample preparation and analysis. The described method was successfully applied to study the pharmacokinetics of berberine as well as lysergol following oral administration in Sprague–Dawley rats. The results of the study inferred that lysergol improved the oral bioavailability of berberine. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Ranjeet S. Bhamber Sergei K. Turitsyn Vladimir Mezentsev 《Optical and Quantum Electronics》2007,39(8):687-692
Effect of the carrier shape in the ultra high dense wavelength division multiplexing (WDM) return to zero differential phase
shift keying (RZ-DPSK) transmission has been examined through numerical optimization of the pulse form, duty cycle and narrow
multiplex/de-multiplex (MUX/DEMUX) filtering parameters. 相似文献
34.
Ranjeet V. Nair Manojkumar R. Shukla Prashant N. Patil Manikrao M. Salunkhe 《合成通讯》2013,43(10):1671-1677
Pseudomonas cepacia lipase supported on ceramic particles (PS-C) offers a simple alternative route for the synthesis of achiral half esters, with very high yields, easy work up and remarkable substrate selectivity, as it cleaves only phenolic esters having a phenyl group (i.e. C6H5-O-CO-C6H5). 相似文献
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Ranjeet Kaur Satyanshu Kumar Arnab Chatterjee Sunil K Chattopadhyay 《Biomedical chromatography : BMC》2010,24(9):1000-1005
A simple, rapid, accurate and reproducible reverse‐phase HPLC method has been developed for simultaneous identification and quantification of three coumarinolignoids, cleomiscosin A (Cliv A), cleomiscosin B (Cliv B) and cleomiscosin C (Cliv C) in different extracts of the seeds of Cleome viscosa using photodiode array detection at 326 nm. Cliv A, B and C were separated on a Waters symmetry C18 column (250 × 4.6 mm, 5 μm) using the solvent system consisting of a mixture of acetonitrile : methanol (1:2 v/v) and water : acetic acid (99.5:0.5 v/v) as a mobile phase in a gradient elution mode. The calibration curves were linear in the concentration ranges 15–200, 10–80 and 15–180 μg/mL for Cliv A, Cliv B and Cliv C, respectively. The limits of detection and quantification for Cliv A, Cliv B and Cliv C were 15 and 20 μg/mL, 10 and 15 μg/mL and 15 and 20 μg/mL, respectively. The intra‐day and inter‐day precisions were 2.08 and 0.93% for Cliv A , 1.22 and 0.39% for Cliv B and 1.29 and 0.23 for Cliv C respectively. The developed HPLC method was used to identify and quantify Cliv A, Cliv B and Cliv C in different extracts of seed of Cleome viscosa. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Templated microporous carbons were synthesized from metal impregnated zeolite Y templates. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were employed to characterize morphology and structure of the generated carbon materials. The surface area, micro- and meso-pore volumes, as well as the pore size distribution of all the carbon materials were determined by N2 adsorption at 77 K and correlated to their hydrogen storage capacity. All the hydrogen adsorption isotherms were Type 1 and reversible, indicating physisorption at 77 K. Most templated carbons show good hydrogen storage with the best sample Rh-C having surface area 1817 m2/g and micropore volume 1.04 cm3/g, achieving the highest as 8.8 mmol/g hydrogen storage capacity at 77 K, 1 bar. Comparison between activated carbons and synthesized templated carbons revealed that the hydrogen adsorption in the latter carbon samples occurs mainly by pore filling and smaller pores of sizes around 6 Å to 8 Å are filled initially, followed by larger micropores. Overall, hydrogen adsorption was found to be dependent on the micropore volume as well as the pore-size, larger micropore volumes showing higher hydrogen adsorption capacity. 相似文献
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Gang Li Penny Xiao Paul Webley Jun Zhang Ranjeet Singh Marc Marshall 《Adsorption》2008,14(2-3):415-422
Capture of CO2 from flue gas streams using adsorption processes must deal with the prospect of high humidity streams containing bulk CO2 as well as other impurities such as SO
x
, NO
x
, etc. Most studies to date have ignored this aspect of CO2 capture. In this study, we have experimentally examined the capture of CO2 from a 12% synthetic flue gas stream at a relative humidity of 95% at 30 °C. A 13X adsorbent was used and the migration of
the water and its subsequent impact on capture performance was evaluated. Binary breakthrough of CO2/water vapor was performed and indicated a significant effect of water on CO2 adsorption capacity, as expected. Cyclic experiments indicate that the water zone migrates a quarter of the way into the
column and stabilizes its position so that CO2 capture is still possible although decreased. The formation of a water zone creates a “cold spot” which has implications
for the system performance. The recovery of CO2 dropped from 78.5% to 60% when moving from dry to wet flue gas while the productivity dropped by 22%. Although the concentration
of water leaving the bed under vacuum was 27%(vol), the low vacuum pressure prevented condensation of water in this stream.
However, the vacuum pump acted as a condenser and separator to remove bulk water. An important consequence of the presence
of a water zone was to elevate the vacuum level thereby reducing CO2 working capacity. Thus although there is a detrimental effect of water on CO2 capture, long term recovery of CO2 is still possible in a single VSA process. Pre-drying of the flue gas steam is not required. However, careful consideration
of the impact of water and accommodation thereof must be made particularly when the feed stream temperature increases resulting
in higher feed water concentration. 相似文献
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Abu Hasnath Md Golam Sarwar Ranjeet Kumar Nirala Mohammed Arif Beena Khillare 《Natural product research》2015,29(12):1166-1169
This study was carried out to assess the spermicidal action of hexane extract from the fruits of Piper longum Linn. The sperm immobilisation studies showed that 20 mg/mL of hexane extract was able to immobilise sperms completely within 20 s. The sperm revival test revealed that the effects were spermicidal as sperm immobilisation effect was irreversible. There was also a significant reduction in sperm viability in the treated group in comparison to the control. The hypo-osmotic swelling of these sperms was significantly reduced, indicating that the hexane extract may probably cause injury to the sperm plasma membrane. Hence, this study showed that the hexane extract of P. longum possesses potential contraceptive spermicidal activity in vitro. 相似文献
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Quantitative determination of saroglitazar,a predominantly PPAR alpha agonist,in human plasma by a LC–MS/MS method utilizing electrospray ionization in a positive mode
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Ashok Ghoghari Ranjeet Dash Chandrakant Bhatt Kanchan Singh Anil Jha Harilal Patel Rahul Gupta Kevinkumar Kansagra Nuggehally R. Srinivas 《Biomedical chromatography : BMC》2016,30(12):1900-1907
A sensitive LC–MS/MS method was developed and validated for quantitation of saroglitazar using turboion spray interface with positive ion mode. A liquid–liquid extraction, with a mixture of dichloromethane and diethyl ether, was employed for the extraction of saroglitazar and glimepiride (IS) from human plasma. The chromatographic separation was achieved using an ACE‐5, C18 (4.6 × 100 mm) column with a gradient mobile phase comprising acetonitrile and ammonium acetate buffer with trifluoracetic acid in purified water. Both analytes were separated within 10 min with retention times of 4.52 and 2.57 min for saroglitazar and IS, respectively. Saroglitazar quantitation was achieved by the summation of two MRM transition pairs (m/z 440.2 to m/z 366.0 and m/z 440.2 to m/z 183.1), while that of IS was achieved using transition pair m/z 491.3 to m/z 352.0. The calibration standards of saroglitazar showed linearity from 0.2 to 500 ng/mL, with a lower limit of quantitation of 0.2 ng/mL. The biases for inter‐ and intra‐batch assays were ?7.51–1.15% and ?11.21 to ?3.25%, respectively, while the corresponding precisions were 5.04–8.06% and 1.53–7.68%, respectively. The developed method was used to monitor the plasma concentrations of saroglitazar in clinical samples. 相似文献