摘要:

Several proteins of varying molecular weights (Mr) were shown to produce a single species, or multiple species which behaved as a single species, upon analysis with capillary isoelectric focusing (cIEF) after derivatization with a large molar excess of the derivatization reagent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Increased molar excesses of reagent were required as the molecular weight (Mr) of the sample increased. The derivative products exhibited acidic pI shifts, improved peak efficiencies, and lowered (improved) detection limits when compared to the native species. In at least one case, a derivative product (not fully tagged) was shown to exhibit antibody (Ab) recognition when challenged with an Ab, raising the possibility of using these derivatives in affinity recognition studies (e.g., affinity CE, immuno-CE, and so forth). Problems were encountered with precipitation during derivatization and focusing. This problem was more pronounced with the more basic proteins. This would appear to limit the applicability of this reagent as a universal derivatization reagent for use with cIEF studies. The results presented herein represent a promising technique, and they offer advantages as well as certain limitations. Though not yet a perfect approach towards improved analysis and identification of peptides in cIEF, these results indicate tangible opportunities for further optimization.

ISSN:1082-6076    

DOI:10.1081/JLC-100100451

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Rate parameters and gradient correlations for nucleic acids are very important to engineering investigations of the separation of DNA products by gradient elution chromatography. Before carrying out computer simulations for gradient process, these rate parameters and gradient correlation must be determined from the experimental data. In this work, moment method was used to calculate the equilibrium adsorption constants (Ki) as a function of the ionic strength (I) of the mobile phase for different sizes of oligonucleotides from the isocratic elution data and later, these coefficient values were used in the computer simulation to predict the elution behavior. This analysis can eliminate extensive experimental trial and error and hence suitable for separation of oligonucleotides and DNA in a more effective manner.

ISSN:1082-6076    

DOI:10.1081/JLC-100100452

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A simple, practical, and economical procedure had been developed to prepare novel C18 ether-bond reversed phase packing. A soft and long C18alkyl chain was coupled onto silica (Sinopak-S, particle size d = 5μm, pore diameter Dp=11nm, and surface area s=170m2/g) with γ-glycidoxypropyltrimethoxysilane as a coupling agent. Characterization of prepared packing was carried out with elemental analysis and solid-state [13]C NMR. Chromatographic evaluation indicates that its reversed phase behavior was similar to ordinary ODS.

ISSN:1082-6076    

DOI:10.1081/JLC-100100453

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Micellar electrokinetic capillary chromatography has been developed as a promising method for the determination of gentiopicroside in plant samples. The separation conditions have been optimised with respect to the different parameters including SDS concentration, pH, and ion strength of the background electrolyte, and temperature of capillary. A buffer consisting of 100 mM SDS in 20 mM sodium dihydrogen phosphate, 20 mM disodium tetraborate pH 8.6 was found to be the most suitable electrolyte for this separation. The applied voltage of 28 kV (positive polarity) and the temperature of capillary 20°C gave the best analysis of gentiopicroside. The linear detection range for concentrationversuspeak area for the assay is from 5 to 500 μg. mL−1(correlation coefficient 0.9998) with a detection limit of 0.3 μg . mL−1. The inter-day reproducibility of the peak area was below 2.5% and the inter-day reproducibility of the migration time was below 0.16 %.

ISSN:1082-6076    

DOI:10.1081/JLC-100100454

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

ACTIVASE® is the recombinant form of human tissue-type plasminogen activator (r-tPA), used in the management of acute myocardial infarction and pulmonary embolism. ACTIVASE® is also now approved for treating ischemic stroke. It is produced by expressing the complementary DNA (cDNA) for natural human tPA in Chinese hamster ovary (CHO) cells. TNK-tPA is a genetically engineered variant of r-tPA with enhanced efficacy and lower incidence of bleeding compared with activase. It was created by three site-directed mutations (T103N, N117Q and KHRR296-299AAAA) and, is also cloned and expressed in CHO cells. CHO cells biosynthesize endogenous hamster tPA called CHO-PA. The amino acid sequence of CHO-PA is highly homologous (80% identical) to that of r-tPA. All three thrombolytic proteins exist as heterogeneous isoforms, mainly due to proteolysis/hydrolysis and differential glycosylation. In this report, a reversed-phase HPLC method was developed to support manufacturing process development. This method not only has the ability to resolve the three plasminogen activators from each other, but also is capable of identifying and quantifying different isoforms of each molecule.

ISSN:1082-6076    

DOI:10.1081/JLC-100100455

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Sucralose is a high intensity, non-nutritive sweetener, which is approximately 600 times sweeter than sucrose. The analysis of this sweetener and similar carbohydrates is challenging, due to both the difficulty of detection as well as the need to separate numerous very similar structures. Capillary Electrochromatography (CEC) was used to analyze sucralose and related carbohydrate compounds. Separation of sucralose and several very similar compounds was achieved by CEC with a C18-silica packing, and low organic content mobile phases. Effects of mobile phase composition on the separation of these compounds are discussed.

ISSN:1082-6076    

DOI:10.1081/JLC-100100456

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A simple reversed phase HPLC method suitable to study the interactions of alkylating agents with DNA is presented in this paper. DNA interaction is expressed as the % DNA peak size exclusion. The effects caused by the antitumor drugs melphalan, busulphan, and busulpan analogues on DNA were clearly observed through chromatographic data. The synthetic dimethanesulphonates of 2-tetradecyl-1,4-butanediol and 1,2-hexadecanediol were proved more potent than busulphan.

ISSN:1082-6076    

DOI:10.1081/JLC-100100457

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Capsazepine is a competitive capsaicin receptor antagonist. Assay method of capsazepine in biological fluid has not been reported yet. We developed a high performance liquid chromatographic (HPLC) method for the determination of capsazepine in rat plasma. A deproteinated serum sample was subjected to an organic phase extraction procedure. The residue was reconstituted in acetonitrile and then an aliquot was directly injected onto an octadecylsilica column. The mobile phase employed was acetonitrile-water (60% acetonitrile in water, v/v). The flow rate was 1.2 mL/min, and capsazepine elution from the HPLC column was monitored by UV absorption at 234 nm. The retention time of capsazepine and YH439 (internal standard) were 4.6 min and 10.8 min, respectively. The detection limit in rat plasma was 0.05 μg/mL. The mean percentage recovery of the drug in the concentration range of 0.05-5 μg/mL was 97.05%, while the inter-day coefficient of variation of the same concentration range was less than 10%. The method for quantitation of capsazepine in rat plasma was accurate and sensitive for in vivo studies.

ISSN:1082-6076    

DOI:10.1081/JLC-100100458

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

An HPLC method for simultaneous identification and quantitation of tocopherols and carotenoids in red palm oil was developed. A C-30 column was used in a HPLC equipped with a photodiode detector and with methyl tertiary-butyl ether/methanol/water as the mobile phase. Tocopherols and carotenoids were monitored at 295 nm and 450 nm, respectively. Gradient elution resulted in complete separation of five tocopherols such as α-, δ-, γ-tocopherols and tocotrienols in palm oil in less than 10 minutes. Several (13) carotenoids were also detected and quantitated in red palm oil within 45 minutes.

ISSN:1082-6076    

DOI:10.1081/JLC-100100459

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Cross-linkedN,N-dimethylaminopropylacrylamide (DMP) spherical particles for the selective removal of lipopoly-saccharides (LPS) from protein solution were prepared. WhenN, N'-buthylene-bis-methacrylamide (BBMA) and divinylbenzene (DVB) were each used as a cross-linking agent and the amino-group content was adjusted to 4.0 meq g−1adsorbent or more, the DMP/BBMA and the DMP/DVB adsorbents showed good LPS adsorption at pH 7.0 and an ionic strength of μ = 0.05 to 0.2. On the other hand, the adsorption of bovine serum albumin, an acidic protein, by each adsorbent increased with the increase in the amino-group content to 4.5 mequiv. g−1adsorbent or larger, but decreased with the increase in the ionic strength (μ) of the buffer to 0.2 or stronger. Only DMP/DVB specifically adsorbed aromatic proteins such as cytochromecand myoglobin, over a wide ionic strength range of μ = 0.05 to 1.0. As a result, when the DMP/BBMA adsorbent which had an amino-group content of 4.0 meq g−1was used in conditions of pH 7.0 and μ = 0.05, LPS was selectively removed from various protein solutions, naturally contaminated with LPS.

ISSN:1082-6076    

DOI:10.1081/JLC-100100460

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor