ISSN:0173-0835    

DOI:10.1002/elps.1150150102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThis survey is aimed at giving the readers a short overview of the present state of the art of clinical and forensic applications of capillary electrophoresis. First, the principles associated with electrokinetic capillary separations and instrumentation, sample preparation and solute quantitation are briefly discussed. This is followed by chapters describing the determination of endogenous and exogenous compounds in body fluids and tissue extracts. Finally, a survey of major achievements including reference to fully developed electrokinetic capillary assays is provided. The paper concludes with a brief outlook.

ISSN:0173-0835    

DOI:10.1002/elps.1150150103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractProtein mixtures can be characterized in terms of their separations by capillary electrophoresis (CE). The separation of proteins by CE is performed in untreated fused‐silica columns. Model proteins and complex protein mixtures with pIvalues ranging from 4.0 to 11.0 are separated in such columns in less than 10 min in the presence of phosphate buffer with a pH between 4.0 and 9.0. The application of CE separation procedures for routine analysis of protein in serum, urine, and cerebrospinal fluid in borate‐based buffer is also demonstrated. The detection of protein in CE is usually based on the intrinsic ultraviolet (UV) absorbance of the peptide bond at or near 200 nm, which provides a detection limit of about 10−5M. The same protein separation procedures can also be applied to immunochemical reaction systems in which one component is labeled. Thus, an antigen analyte, or the antibody to the analyte, may be labeled with a fluor and detected by laser‐induced fluorescence (LIF). With a fluorescent‐labeled reactant, the use of LIF detection further extends the detection limit to 10−11M. The CE separation technique for proteins provides a means to separate the bound and free species of the labeled antigen or antibody without the use of a solid support. The application of these separation techniques in conjunction with laser‐induced fluorescence detection to make possible the homogeneous immunochemical measurement of species at concentrations in the range of 10−9to

ISSN:0173-0835    

DOI:10.1002/elps.1150150104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractCapillary isoelectric focusing (CIEF) with electroosmotic zone displacement of normal and pathological hemoglobins (Hb) is reported. CIEF is performed in untreated, open‐tubular, fused‐silica capillaries of 75 μm internal diameter using methylcellulose for dynamic column conditioning. After direct injection of hemolysates mixed with carrier ampholytes, high resolution separation of Hb variants, including Hb A1c, A, F, D, S, E and A2, is obtained, this permitting unambiguous characterization of Hb patterns of normal adults, newborns, patients with diabetes, different hemoglobinopathies and thalassemia syndromes. Qualitatively, the CIEF data compare well with those obtained by gel isoelectric focusing and high‐performance liquid chromatography. CIEF is demonstrated to be a simple, rapid and fully instrumental approach to Hb analysis. Run times of less than 20 min make CIEF an attractive method for routine Hb investigations and screening pr

ISSN:0173-0835    

DOI:10.1002/elps.1150150105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractAn analytical free flow capillary isotachophoresis procedure, with a discontinuous electrolyte system, for the detailed analysis of lipoproteins in human body fluids has been developed. The technique is based on prestaining whole serum lipoproteins with a lipophilic dye before separation. Human serum lipoproteins are separated into 14 well‐characterized subfractions according to their electrophoretic mobility. High density lipoproteins (fraction 1 to 6) are separated into three major subpopulations, the fast migrating high density lipoprotein (HDL) subpopulation, containing mainly apo AI and phosphatidylcholine, the subpopulation with intermediate mobility, consisting of particles rich in apo AII, apo E, and C apolipoproteins, and the slowly migrating HDL subfraction, containing mainly particles rich in apo AI, apo AIV, and lecithin: cholesterol acyltransferase (LCAT) activity. The apo B containing lipoproteins (fraction 7 to 14) can be subdivided into four major functional groups. The first represents chylomicron derived particles and large triglyceride‐rich very low density lipoproteins (VLDL). The second group consists of small VLDL and intermediate density lipoprotein (IDL) particles, anf the third and fourth group represent the low density lipoproteins. The isotachophoretic analysis of human serum samples obtained from patients with hyperlipoproteinemias is compatible with the classification according to the Frederickson phenotypes and reflects the respective biochemical abnormalities. Furthermore, several genetic disorders of lipid and lipoprotein metabolism like HDL deficiency syndromes, familial LCAT deficiency, Fish eye disease, hypobetalipoproteinemia and abetalipoproteinemia can be well characterized by analytical capillary iso tachophoresis. In addition to patient analysis we investigated the influence of lipid lowering drugs on the lipoprotein subfraction distribution during therapy with analytical capillary isotachophore

ISSN:0173-0835    

DOI:10.1002/elps.1150150106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

Abstract2—5A Synthetase and 2—5A phosphodiesterase were determined by analytical capillary isotachophoresis in comparison to radioenzymatic methods. By means of isotachophoretic analysis, a frequently used radioenzymatic 2—5A synthetase assay was optimized and the results of both assays were compared. Using the isotachophoretic assay the influence of interferon‐related cytokines (tumor necrosis factor‐alpha and interleukine‐2) on 2—5A synthetase induction in neuroblastoma cells was estimated. In contrast to mononuclear blood cells, the tumor necrosis factor induced 2—5A synthetase in these cells. 2—5A Phosphodiesterase was determined using an isotachophoretic assay and a radioenzymatic method. Degradation of A2′p5′A2′p5′A (trimeric form of 2—5A core) was measured by isotachophoresis whereas degradation of a mixture of phosphorus‐32 labeled 2—5A cores was registrated by radioenzymatic assay. Activity of 2—5A phosphodiesterase was only insignificantly enhanced by interferon in mononuclear blood and neuroblastoma cells. In contrast to the radioenzymatic assays, an accurate determination of 2—5A synthetase as well as of 2—5A phosphodiesterase is possible using the isotachophoretic method because the reactions are followed by measuring the substrate

ISSN:0173-0835    

DOI:10.1002/elps.1150150107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractAn electrophoretic method for detecting neurotensin in tissues was developed. Homogenates of rat duodenum and adrenal glands were first extracted by solid‐phase extraction and purified by reversed‐phase high‐performance liquid chromatography. The neurotensin‐rich fraction was further analyzed by capillary zone electrophoresis (CZE) using a commercial instrument with UV detection. A minor peak was detected as neurotensin and its identity was further confirmed by performing several CZE analyses at different pH values. Such an approach could be used to analyze with good molecular specificity the neuropeptides in some human

ISSN:0173-0835    

DOI:10.1002/elps.1150150108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractFactors influencing the establishment of an analytical window in front of the solubilized proteins in micellar electrokinetic capïllary chromatography (MECC) with direct serum injection (DSI) are discussed. Both drugs and endogenous low molecular mass compounds eluting within the analytical window are identified concurrently by multi‐wavelength absorption detection. Variables such as the concentration of the micelle forming substance, ionic strength, applied voltage, initial sample zone length, capillary length, selected buffer additives, insufficient renewal of the buffer in the anodic buffer vial and sample matrix are shown to impact MECC of endogenous compounds and model drugs, such as antiepileptics. For two drugs eluting within the analytical window, phenobarbital and ethosuximide, serum levels determined by DSI with external calibration are shown to compare well with levels obtained after liquid‐liquid extraction and internal calibration (use of an internal standard). In addition, reproducibility of both assays is excellent. The limit of employing DSI is demonstrated with the determination of the hydrophobic drug phenytoin. Using an automated, commercial instrument and naproxen as model drug, high‐speed MECC separations of high reproducibility and with a throughput of 12–15 samples per h are p

ISSN:0173-0835    

DOI:10.1002/elps.1150150109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe application of capillary electrophoresis (CE) with photodiode array detection (DAD) and on‐line CE‐mass spectrometry (CE‐MS) equipped with a position and time resolved (PATRICtm) focal plane detector for analysis of bothin vitroandin vivodrug metabolism is demonstrated. Separation of metabolites derived from the neuroleptic drug haloperidol, by CE, using a simple, volatile run buffer containing 50 mMammonium acetate with 10% methanol and 1% acetic acid is reported. The potential utility of CE‐DAD for screening drug metabolite mixtures derived from hepatic microsomal incubations is demonstrated for haloperidal (HAL). Also the potential problems associated with using this technology to screen human urine samples for HAL metabolites is discussed. Furthermore, the usefulness of CE‐MS and CE‐electrospray ionization skimmer collision induced dissociation‐MS (CE‐ESI‐CID‐MS) in identification and structure elucidation of HAL metabolites derived from both a guinea pig hepatic microsomal incubation and urine from a patient treated with 0.5 mg/day of HAL is shown. The utility of such an approach in the general area of clinical pharmacolog

ISSN:0173-0835    

DOI:10.1002/elps.1150150110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThe determination of the major urinary compounds of eight common benzodiazepines, flunitrazepam, diazepam, midazolam, clonazepam, bromazepam, temazepam, oxazepam, and lorazepam, by micellar electrokinetic capillary chromatography (MECC) is shown to be a simple and attractive approach for confirmation testing of these drugs in human urine. After enzymatic hydrolysis and extraction using mixed‐mode solid‐phase cartridges and a two‐step elution protocol, fractions were analyzed in a phosphate/borate buffer (pH 9.3) containing 75 mMsodium dodecyl sulfate and small amounts of isopropanol, methanol and/or acetonitrile using an instrument with on‐ column multi‐wavelength detection. The presence of these compounds could unambiguously be confirmed in patient urines which tested positive for benzodiazepines using a commercial enzyme multiplied immunoassay screening technique (EMIT). The sensitivity of the MECC assay is demonstrated to be better than that of EMIT. MECC analysis of one patient urine which tested negatively employing EMIT revealed the presence of lorazepam, this demonstrating that false‐negative results from the initial immunological screening process can be recognized using MECC. For one example, 7‐aminoflunitra‐zepam, the MECC data are shown to agree well with those obtained by gas chromatography/ma

ISSN:0173-0835    

DOI:10.1002/elps.1150150111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY