摘要:

Immunoaffinity chromatography can be applied to the treatment of biological samples. It consists of the separation, extraction, or purification of a molecule (para nitro analine in this paper) from a mixture by a selective interaction with an antibody. The latter is produced by living organisms after their contact with an antigen (modified protein in this case). The production of specific antibodies highly depends on the purity of antigen. This paper describes and compares two methods of antigen purification: dialysis and gel permeation chromatography. This chromatographic method allows one to obtain a pure antigen faster than dialysis but with a slightly larger dilution of the samples. It is not a drawback for the procedure of the antibodies production.

ISSN:1082-6076    

DOI:10.1081/JLC-100101466

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Purification of PEG-protein conjugates by countercurrent distribution (CCD) in aqueous two-phase systems is reported. By using CCD in 19.36% PEG 3400/14.68% potassium phosphate, we can separate PEG-lysozyme conjugates, which contains an average number of 1.14 PEG per lysozyme, into three peaks with 55 number of transfers. Further analysis of the samples reveals that these three peaks mainly represent unmodified lysozyme, (PEG)1-lysozyme and (PEG)2-lysozyme.

ISSN:1082-6076    

DOI:10.1081/JLC-100101467

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The retention, UV absorbance, and electrochemical response of adenosine and some of its precursors and metabolites under varying mobile phase composition was investigated using a UV detector on line with an electrochemical detector. The primary interest was focused on adenosine. Experimental retention data sets of this compound obtained on two columns in buffered mobile phases of different pH values modified with methanol and/or acetonitrile were fitted through adequate equations. The physical meaning of the fitted parameters was discussed, besides the dependence of these equation coefficients on the type of organic modifier and composition of mobile phase. The possibility of predicting the retention behaviour of adenosine on the basis of a limited number of data was also explored.

ISSN:1082-6076    

DOI:10.1081/JLC-100101468

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In this paper, a method is described that makes easier application of Chang's method for the determination of molecular weight of copolymers by GPC. Determinations of molecular weight of EP-copolymers have been performed with this method. The values of the resultant weight- and number-average molecular weight are rather close to the experimental data, and the values of intrinsic viscosity [η]care close to the values measured with Ubbelodhe viscometers [η]d.

ISSN:1082-6076    

DOI:10.1081/JLC-100101469

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Thin-layer chromatography has several advantages in comparison to column chromatography, e.g., simultaneous separation of several samples, easy realization of two-dimensional separation, direct observation of both the chromatographic development and the separation using colored compounds, sensitive and easy detection of the spots with specific spray reagents. The entire procedure, i.e., loading, development, and evaluation are relatively simple. An additional feature is the optimization possibilities of mobile phase flow velocity, based on the complexity of driving force where capillarity results in a concave flow profile that may be counterbalanced by convex profile of laminar flow. Displacement thin-layer chromatography has the advantages of planar arrangement of the stationary phase, and opens new possibilities for analytical separations.

ISSN:1082-6076    

DOI:10.1081/JLC-100101470

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This work presents a method for qualitative and quantitative analysis of selected organic peresters. The method is based on RP-HPLC measurements, using a mixture of acetonitrile and water as a mobile phase. This technique appears to be fast, simple, and precise. The obtained results were found to be highly reproducible. The relative standard deviations are within the range of 0.1–0.7%.

ISSN:1082-6076    

DOI:10.1081/JLC-100101471

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

An improved method for the determination of phentolamine in human plasma samples was developed. After being alkalinized, plasma samples (1 mL) were extracted with diethyl ether and then back-extracted with O.1 N HCl. Analyses were carried out on a Novapak C8 column eluted with a mixture of sodium monochloroacetate (pH 3) and acetonitrile (75:25). Amperometric detection was performed by oxidation at 1000 mV, using a glassy carbon electrode against Ag/AgCl. Calibration curves, constructed over a 1 to 30 ng/mL plasma concentration range, were linear (r=0.999). Intra-assay coefficients of variation and accuracy for the determined concentrations were comprised within 7.6–10.9% and 94.0–105.6%, respectively. Inter-assay coefficient of variation and accuracy ranges were 10.4–20.7% and 93.2–102.7%, respectively. The method's detection limit was 0.2 ng/mL, allowing determination of oral phentolamine pharmacokinetics after administration of a 40 mg dose.

ISSN:1082-6076    

DOI:10.1081/JLC-100101472

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A stability indicating high performance liquid chromatography method has been developed for simultaneous determination of acetaminophen, salicylamide and phenyltoloxamine. The reversed-phase method utilizes UV detection at 220 nm and a C8 column. This paper presents the data to support linearity, precision, specificity, and robustness of the method. The known potential degradation products of acetaminophen, p-aminophenol, p-nitrophenol, precursor impurity p-hydroxyacetophenone, the potential degradation product of salicylamide, salicylic acid, and precursor impurity ethylsalicylate were separated for quantitation simultaneous with parent compounds. Quantification was achieved by peak area and external standard method. This method can be employed in determining stability, assay, content uniformity, and dissolution of the combination in pharmaceutical dosage forms.

ISSN:1082-6076    

DOI:10.1081/JLC-100101473

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

As research on the biodegradation of benzo[a]pyrene (B[a]P) shifts from laboratory to field based studies, a need has arisen for reproducible, economical, and accurate methods for extraction and quantification of B[a]P. This study describes a method for the analysis of B[a]P using batch extraction techniques with quantification by reversed phase high performance thin layer chromatography (HPTLC) and densitometry. A loam soil was fortified with B[a]P at a level of 100 mg B[a]P kg−1soil. Several solvents were evaluated as potential soil extraction systems including: acetone, acetonitrile, ethyl acetate, methanol, and methylene chloride:acetone (1:1). Reverse phase thin layer chromatography of B[a]P was performed on hydrocarbon impregnated, C18reverse phase plates using methanol:acetonitrile (1:1) as the developing solvent. The Rf for B[a]P in this system was found to be 0.52. Recovery of B[a]P from soil ranged from 11% with methanol to 84% with ethyl acetate.

ISSN:1082-6076    

DOI:10.1081/JLC-100101474

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A high performance liquid chromatographic (HPLC) method was developed for the determination of phenobarbital in human breast milk and plasma. The chromatographic behaviors of phenobarbital and other barbiturate derivatives on various sorbents, including octadecyl (C18), octyl (C8), methyl (C1), cyanopropyl (CN), phenyl (Ph), and dimethyl tert-butyl (tert-But), were investigated as stationary phases, and then chromatographic separation was achieved by C8analytical column using a potassium dihydrogenphosphate buffer (pH 3.5 for milk, pH 6.5 for plasma) / acetonitrile (70 : 30, v/v) as the mobile phase because interference peaks affected differently in each specimen. Phenobarbital and 5-methyl-phenobarbital as an internal standard were detected by ultraviolet detection method at 230 nm. Phenobarbital was extracted by a rapid and simple procedure based on C18bonded-solid phase extraction in breast milk and plasma.

ISSN:1082-6076    

DOI:10.1081/JLC-100101475

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor