نتایج جستجو برای: c18 column

تعداد نتایج: 77572  

Journal: :Clinical chemistry 1982
J Lehmann H L Martin

Tocopherols extracted from plasma with methanol or from platelets with chloroform/methanol were injected in methanol on a reversed-phase (C18) "high-performance" liquid-chromatographic column and eluted with water/methanol (2/98, by vol) at a flow rate of 1.4 mL/min. A "high-performance" spectrophotofluorometer was used for detection. Analytical recoveries ranged from 89 to 106%. The response w...

2003
Andrzej Posyniak Jan Zmudzki Jolanta Niedzielska Tomasz Sniegocki Agnieszka Grzebalska

The suitability of analytical protocol for determination of sulfonamides in honey was investigated. Sulfonamides were extracted from honey with acetate buffer, and cleaned up by solid phase extraction (SPE) procedure. The liquid chromatography (LC) separation was carried out on RP C18 column and sulfonamides were monitored with fluorescence detector, after pre-column derivatisation. Recoveries ...

2014
MR Trapani MG Parisi M Toubiana L Coquet T Jouenne P Roch M Cammarata

We investigated the antibacterial activity of Anemonia sulcata (Cnidaria, Anthozoa) tentacle and body acidic extracts. Biochemical purification consisted of first step on solid phase Sep-Pak C8 column followed by several HPLC runs on C18 column using different conditions. Anti-Micrococcus lysodeikticus activity has been detected in 40 % acetonitrile fractions. The resulting purified molecule fr...

Journal: :Analytical chemistry 2003
Vladimir V Tolstikov Arjen Lommen Kazuki Nakanishi Nobuo Tanaka Oliver Fiehn

Application of C18 monolithic silica capillary columns in HPLC coupled to ion trap mass spectrometry detection was studied for probing the metabolome of the model plant Arabidopsis thaliana. It could be shown that the use of a long capillary column is an easy and effective approach to reduce ionization suppression by enhanced chromatographic resolution. Several hundred peaks could be detected u...

Journal: :Clinical chemistry 1988
Y Imai S Ito K Maruta K Fujita

We describe a liquid-chromatographic method for simultaneously determining norepinephrine, epinephrine, dopamine, and serotonin in 0.5 mL of human plasma. These analytes are purified on boric acid gel from Aldrich, separated on a reversed-phase C18 column, and detected electrochemically at +600 mV. Absolute recoveries of internal standards were 84% for 3,4-dihydroxybenzylamine and 57% for N-met...

Journal: :Clinical chemistry 1984
R L Heideman K B Fickling L J Walker

This is a simple, rapid, sensitive method for routine quantification of the polyamine putrescine (1,4-diaminobutane) in cerebrospinal fluid. Sample preparation involves protein precipitation, acid hydrolysis for 18 h (if total putrescine is to be measured), pre-column derivatization with o-phthalaldehyde, and extraction into acetonitrile. The derivative is separated and quantified by "high-perf...

Surface Molecularly Imprinted Polymer (SMIP) for selective adsorption of di(2-ethylhexyl) phthalate(DEHP) was prepared on the surface of silica gel which was modified by aminopropyltriethoxysilane and acryloyl chloride in a two-step method. The prepared SMIP was used to prepare Molecularly Imprinted Solid-Phase Extraction (MISPE) column for selective extraction of DEHP from aqueous solution...

2012
M. P. MAHAJAN S. D. SAWANT

A novel, simple and economic reverse phase high performance liquid chromatography (RP-HPLC) Stability indicating method has been developed for the estimation of zolpidem tartrate in bulk and tablet dosage form with greater precision and accuracy. Separation was achieved on C18 column (250X4.6mm i.d.,5μm) in isocratic mode using methanol and acetonitrile in the ratio 50:50 (v/v) as mobile phase,...

2005
Nam-Hee Yoo Ick-Dong Yoo Jin-Woo Kim Bong-Sik Yun In-Ja Ryoo Eui-Soo Yoon Nguyen Thi Chinh Jong-Pyung Kim

Structurally new antioxidative metabolite was isolated from mycelial culture of mushroom Stereum hirsutum. Culture broth was subjected to Diaion HP-20 column chromatography, and 70% aqueous MeOH eluent was extracted with EtOAc. EtOAc extract was purified through silica gel and Sephadex LH-20 column chromatographies, and reversed phase C18 HPLC. Compound was revealed to be new dihydroxylated der...

Journal: :Journal of chromatographic science 2001
W Li J F Fitzloff

A reverse-phase high-performance liquid chromatographic method is developed for the determination of astragaloside IV, a characteristic constituent in Radix Astragali. Samples are analyzed by means of a reverse-phase column (Zorbax Eclipse XDB C18) using acetonitrile and water under gradient conditions as the mobile phase for 30 min. An evaporative light-scattering detector is used and set at a...

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