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At least 703 records · Page 39Linked to original sources
PubMed1977

Rapid antibody production and sample preparation for radioimmunoassay of prostaglandin A.

A dialysis equilibrium method for plasma or tissue preparation for radioimmunoassay of prostaglandins is presented and compared to the silica gel column technique. The plasma or tissue is extracted, dried, redissolved in buffer and dialyzed for further purification before assay. Results comparing both methods shows that dialysis equilibrium greatly simplifies the silica gel column technique yet preserves specificity, sensitivity and reproducibility. In addition a rapid micromethod for the development of a specific antibody to prostaglandin A is detailed.

Animals↗
PubMed1990

Effective sample preparation method for extracting biologically active compounds from different matrices by a microwave technique.

A method is described for extracting lupin alkaloid (sparteine) and drug metabolites from different matrices (seeds and rat faeces) using microwave energy and for checking the homogeneity of the electric field in the microwave oven. The high-performance liquid chromatographic separation and determination of the extracted compounds showed that the microwave extraction method is more advantageous than other traditional extraction methods with regard to the yield of extraction and the time and cost of the procedure. The potential degradation of the extracted compounds may be considerably reduced.

Animals↗
PubMed1993

Chemometrics in bioanalytical sample preparation. A fractionated combined mixture and factorial design for the modelling of the recovery of five tricyclic amines from plasma after liquid-liquid extraction prior to high-performance liquid chromatography.

A general systematic approach is described for the chemometric modelling of liquid-liquid extraction data of drugs from biological fluids. Extraction solvents were selected from Snyder's solvent selectivity triangle: methyl tert.-butyl ether, methylene chloride and chloroform. The composition of a mixture of the three extraction solvents was varied and the extraction yield (recovery) of a group of tricyclic amines was measured at all compositions selected. Two process variables, the extraction time and the extraction intensity, were varied simultaneously with the mixture variables to study their influence and their interaction with the mixture composition. The combined mixture and factorial design statistical techniques obtained in this way enabled the recovery to be modelled as a function of both the composition of the extraction liquid and the process variables. The models were assessed with regard to both descriptive and predictive capacities. The results showed that structurally related compounds may demonstrate different partitioning behaviour with regard to both mixture variables and process variables. It was concluded that mixtures of solvents result in higher extraction efficiencies for the amines. A positive effect on the extraction efficiency was demonstrated by the extraction intensity process variable and extraction time. A positive effect on the extraction efficiency was demonstrated by an interaction between extraction intensity and time. Mixture models in which process variables were introduced were recognized as being very suitable for modelling liquid-liquid extraction systems.

Antidepressive Agents, Tricyclic↗
PubMed1996

High-performance liquid chromatographic evaluation of biogenic amines in foods. An analysis of different methods of sample preparation in relation to food characteristics.

Biogenic amines are compounds formed by amino acid decarboxylation in fermented foods. Most of the methods for amine determination involve acid extraction followed by a liquid-liquid purification step. The different parameters which can influence amine recoveries are considered; experience with different foods such as cheese, fish and meat preserves are reported and for each of them the optimized analytical procedure is described. Data concerning recovery and repeatability of the method are also reported and the various factors that influence amine extraction are discussed. The possibility of applying direct derivatization without any other purification step is also considered.

Biogenic Amines↗
PubMed1993

Analyses of volatile C2 haloethanes and haloethenes in tissues: sample preparation and extraction.

A tissue extraction procedure was developed which minimized loss of readily volatilizable compounds for subsequent quantification by headspace gas chromatography, and evaluated for perchloroethylene (PER), 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, and 1,1,2-trichloroethylene. Of the procedures evaluated, joint isooctane and saline tissue homogenization had the most efficient recovery, ranging from 73 to 104% for the four halocarbons from seven different rat tissues. PER concentrations were also determined in tissues of rats following in vivo halocarbon administration. Recovery did not appear to be tissue-dependent, but did vary somewhat with test chemical, with the least volatile, most lipophilic compounds exhibiting the highest recovery.

Animals↗
PubMed1994

Robotic sample preparation and high-performance liquid chromatographic analysis of verlukast in human plasma.

A fully automated HPLC assay has been developed and validated for the quantitation of verlukast, a leukotriene D4 antagonist, in human plasma. An upgraded Zymate I robotic system was utilized to perform protein precipitation and on-line injection followed by reversed-phase HPLC with fluorescence detection. Inter-day accuracy and precision were 100.8 and 4.6%, respectively, for the low quality control standards (0.125 microgram/ml). The automated robotic method was shown to be more efficient and accurate than the manual method.

Bronchodilator Agents↗
PubMed1996

Determination of alosetron in human plasma or serum by high-performance liquid chromatography with robotic sample preparation.

A method of analysis for the determination of alosetron in human plasma or serum has been developed. The method was fully automated using a laboratory robot in order to improve analytical precision, efficiency and safety. The assay involved solid-phase extraction with reversed-phase HPLC separation and fluorescence detection. A validation exercise over the concentration range of 0.1 to 20 ng/ml demonstrated the selectivity, linearity, sensitivity, accuracy, precision, extraction efficiency, ruggedness and stability of the method. The method has been applied in support of numerous human pharmacokinetic/biopharmaceutic studies over the last five years.

Carbolines↗
PubMed1996

Advances in sample preparation, electrophoretic separation and detection methods for rat cytochrome P450 enzymes.

A limited overview is given of the separation and detection of specific cytochrome P450 enzymes of the rat. Separation methods include group-specific chromatographic separation and electrophoretic separation in and elution from polyacrylamide gels. Detection methods that are considered include enzymatic analysis with and without chromatographic step using liquid chromatography and immunochemical methods following separation of the cytochrome P450 enzymes by polyacrylamide gel electrophoresis (Western blotting). The advantages and limitations of the various methods have been compared and discussed.

Animals↗
PubMed1996

Automated polymerase chain reaction product sample preparation for capillary electrophoresis analysis.

The analysis of crude polymerase chain reaction (PCR) products by capillary electrophoresis (CE) is often compromised due to the presence of a high concentration of salt. Salt interferes with the electrokinetic injection and induces localized heating within the column; hence, PCR products must be desalted or cleaned-up prior to CE analysis. A variety of commercial clean-up systems are available that have been traditionally used to prepare PCR products for cloning, sequencing and digestion with restriction enzymes. These systems were tested for their effectiveness in preparing PCR products for CE analysis and were evaluated based on CE resolution, salt removal, DNA recovery, processing time and cost. One particularly effective clean-up system, membrane dialysis, was automated using a robotic workstation.

Automation↗