Injection-generated solvent and pH gradients for sample enrichment on injection of large volumes in microcolumn liquid chromatography

Poster (1995)

Validation of bioanalytical methods

in Journal de Pharmacie de Belgique (1995), 50

Automated determination of camazepam in human plasma by solid phase extraction coupled to HPLC

in Journal de Pharmacie de Belgique (1995), 50

On-line combination of dialysis and liquid chromatography for the automated determination of oxprenolol in human plasma

in Journal de Pharmacie de Belgique (1995), 50

Comparison of solid-phase extraction and dialysis as on-line sample preparation procedures for the automated HPLC determination of verapamil and norverapamil in human plasma

in Journal de Pharmacie de Belgique (1995), 50

Automated solid-phase extraction coupled to HPLC for the determination of drugs in biological fluids

in Pharmacy World & Science [=PWS] (1995), 17

A fully automated HPLC method for pharmacokinetic studies on a long-acting sulfamethazine veterinary bolus

Conference (1995)

Knowledge-Based System for the Automated Solid-Phase Extraction of Basic Drugs from Plasma Coupled with Their Liquid Chromatographic Determination. Application to the Biodetermination of Beta-Receptor Blocking Agents

in Journal of Chromatography. A (1994), 665(1), 87-99

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges ... [more ▼]

Techniques for the preparation of biological samples are often based nowadays on solid-phase extraction (SPE). The different SPE steps can be performed automatically on disposable extraction cartridges (DECs) by means of a sample processor. A knowledge-based system was developed to facilitate the development of fully automated methods for the solid-phase extraction of relatively hydrophobic basic drugs from plasma, coupled with their determination by high-performance liquid chromatography (HPLC). The DEC filled with 50 mg of cyanopropyl-bonded silica phase is first conditioned with methanol and buffer solution (pH 7.4). After sample application, the DEC sorbent is washed with the same buffer. The analytes are then desorbed with an appropriate eluent and the eluate is finally diluted with the same buffer as used in the HPLC mobile phase before injection. Under these conditions, only three variables are still to be optimized: the composition and volume of the elution solvent and the volume of buffer to be added to the eluate. On the basis of this general strategy, a decision tree providing information about suggested starting conditions and guidelines for the optimization of the three variables was developed and implemented by use of a hypermedia software. This didactic expert system was evaluated using several beta-receptor blocking agents as model compounds and the operating conditions obtained for the automated SPE of these compounds are presented. A method for the determination of propranolol in plasma using the SPE conditions deduced from the knowledge-based system was validated. The absolute recovery of propranolol is ca. 93% and the limit of detection is 1.3 ng ml-1. The mean within-day and between-day reproducibilities are 2.3 and 3.6%, respectively. [less ▲]

Development of an automated solid phase extraction method coupled to HPLC for the determination of some benzodiazepines in plasma by use of a knowledge-based system

in Journal de Pharmacie de Belgique (1994), 49

HPLC determination of some -adrenergic blocking agents in plasma using automated solid-phase extraction and fluorometric detection

Poster (1994)