摘要:

AbstractA highly sensitive and selective method for the determination of spermidine and spermine has been developed. A polyamine oxidase (Aspergillus terreus) immobilized column was used as a postcolumn reactor. The detection limit was 0.2 pmol/injection for both spermidine and spermine with a linear range of three orders of magnitude.

ISSN:0269-3879    

DOI:10.1002/bmc.1130060102

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes a method for the direct gas/liquid chromatographic (GC) analysis of 46 glycine‐conjugated bile acids, which differ from one another in the number, position and configuration of the hydroxyl groups at positions C‐2, C‐3, C‐4, C‐6, C‐7 and/or C‐12. Free bile acids were converted quantitatively on a micro scale to ethyl ester‐trimethylsilyl (Et‐TMS) and methyl ester‐dimethylethylsilyl (Me‐DMES) ether derivatives of the corresponding glycine conjugates. The Et‐TMS and Me‐DMES ethers of the glycine conjugates were chromatographed on an aluminum‐clad flexible fused‐silica capillary column coated with a thin film (0.1 μm) of chemically bonded and cross‐linked methylpolysiloxane. Relative retention time (RRT) and methylene unit (MU) values were determined for the 46 compounds and their GC behaviour was discussed. The derivatization procedure and the retention data would be useful for the direct GC identification of unknown glycine‐conjugated bile acid mixtures

ISSN:0269-3879    

DOI:10.1002/bmc.1130060103

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA specific method for the determination of 10α‐methoxy‐9,10‐dihydrolysergol, a nicergoline metabolite (metabolite 2), in urine is described. Metabolite 2 was well separated from the urine components on a reversed phase column, Hypersil ODS 5 μm, using an acetonitrile: pH 3.5 phosphate buffer (40:60, v/v) as the mobile phase at a flow rate of 1 mL/min. UV detection was set up at 220 nm. After addition of a known amount of lysergamide as the internal standard, the compounds were extracted from alkalysed urine on a pre‐packed glass column (Extrelut 1) with dichloromethane. With 0.5 mL urine, concentrations down to 0.56 μmol/L could be

ISSN:0269-3879    

DOI:10.1002/bmc.1130060104

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA gas chromatographic/mass spectrometric procedure has been developed for the quantiation in human plasma of the enatiomers of rimanatadine and its three hydroxylated metabolites. The assay utilized derivatization of all analytes with the optically active reagent S‐α‐methyl‐α‐methoxy(pentafluorpheyl)acetic acid, selective ion monitoring, methane negative ion chemical ionization mass spectrometry and stable isotope dilution techniques. This method has been used to meausure plasma concentrations of the enantiomers of rimantadine,m‐hydroxyrimantadine andp‐hydroxyrimantadine (equatorial and axial epimers) in the ranges 2.5‐250, 2.5‐50, 1.25–62.5 and 1.25–62.5 ng/mL, respectively, in six subjects given a single 200 mg dose of racemic rimantadine. Although there are no significant differences in the concentration‐time profiles ofR‐ andS‐rimantadine, large stereospecific differences in the disposition of the

ISSN:0269-3879    

DOI:10.1002/bmc.1130060105

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA sensitive and specific high performance liquid chromatographic method is described for measuring imidazole dipeptides and 3‐methylhistidine in human muscle biopsies, serum and urine. Muscle extract, serum or urine was reacted witho‐phthaldialdehyde and the derivatives were separated by reversed phase chromatography with column swithing and fluorescence detect

ISSN:0269-3879    

DOI:10.1002/bmc.1130060106

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA rapid, specific and reliable gas chromatographic assay procedure for Nifedipine in plasma has been developed. With a single‐step solvent extraction, and electron capture detection, the method is sensitive to 0.5 ng/mL of plasma and the standard curve is linear from 0.5 to 500 ng/mL. Samples are protected from light to prevent formation of photodecomposition products. The method has been used to monitor drug concentrations in patients receiving therapeutic dose

ISSN:0269-3879    

DOI:10.1002/bmc.1130060107

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA method for the determination of the antiepileptic drug valproic acid and 14 of its metabolites in serum and urine by gas chromatography/mass spectrometry with selected ion monitoring of the trimethylsilylated derivatives has been developed. Sample preparation, including hydrolysis of VPA‐conjugates and removal of urea in urine is carried out at pH 5.0 and is rapid and simple. The samples are extracted with ethyl acetate and the concentrated extracts are trimethylsilylated. Analysis with adequate separation of metabolites is achieved with a DB 1701 fused silica (Megabore) capillary column. The method exhibits high recovery and reproducibility and is sufficiently sensitive and selective for analysis of small sample volumes. Application of the method for screening patient serum and urine samples for unusual metabolite patterns, with possible predictive value for early detection of liver injury, is presente

ISSN:0269-3879    

DOI:10.1002/bmc.1130060108

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe high performance liquid chromatographic (HPLC) separation and identification of 12 isomeric and/or highly chemically related steroids with an unsaturated ester moiety at position 17β has been achieved. The main stereochemical features of the steroid skelton cover 3α/β or Δ, and 20E/Z, bearing the alcohol or hemisuccinate group at the 3 position. The isocratic reversed phase C18HPLC separation employed ethanol, methanol and its mixtures with water or 0.01 M phosphoric acid as the mobile phase. The best separaton of the respective alcohols from their hemiscuccinates has been achieved with 20% of aqueous phase content. The best separation among isomeric or related steroids has been achieved with methanol: water 8:2 and 85:15 and similar systems containing phosphoric a

ISSN:0269-3879    

DOI:10.1002/bmc.1130060109

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractA simple and rapid method for analysis of the core of 2′,5′‐oligoadenylates, mainly based on the use of high performance liquid chromatography (HPLC), is described. Perchloric acid extracts of tissues or cells were first treated with nuclease P1. Portions of the extracts were then digested with alkaline phosphatase. HPLC analysis of the extracts was performed on a column system composed of an Ultrasphere ODS precolumn (4.6 × 45 mm) and an Ultrasphere Octyl column (4.6 × 250 mm) by stepwise elution using a 50 mM ammonium phosphate buffer, pH7, containing 3.5 and 7% methanol. Three species of the core of 2′,5′‐oligoadenylates (dimer, trimer and tetramer) from a number of samples were eluted separately with 7% methanol, and the concentration of each core was directly estimated using constant values calculated with the standard core. The level of the core of 2′,5′‐oligoadenylates in tissues and cells determined by our method is similar to that reported by other authors who used biological, radiobinding or radioi

ISSN:0269-3879    

DOI:10.1002/bmc.1130060110

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY

摘要:

AbstractBlood group B antigenic trisaccharide‐β‐aminopropyl glycoside (B‐TSAP) covalently attached to poly‐N‐(2‐hydroxyethyl)acrylamide‐coated porous glass interacts with anti‐B monoclonal antibodies faster than the ligand coupled to CNBr‐activated Sepharose 4B and Affi‐Gel 10. Rates of hydrophobic adsorption of antibodies on the butyl derivatives of the same supports were measured to evaluate the diffusion input to overall kinetics. The lowest average affinity adsorption time [t1(aff) = 250 s] observed for polymer‐coated glass probably arises because of the flexibility of the extended segments of chemisorbedN‐substituted polyacrylamide acting

ISSN:0269-3879    

DOI:10.1002/bmc.1130060111

出版商:John Wiley&Sons, Ltd.    

年代:1992

数据来源: WILEY