Guido Van der Weken

Chemiluminescence Determination of Tiopronin by Flow Injection Analysis Based on Cerium(IV) Oxidation Sensitized by Quinine

A flow injection analysis method is proposed for the determination of tiopronin based upon the oxidation by cerium(IV) in dilute sulfuric acid medium and sensitized by quinine. With the peak height as a quantitative parameter applying optimum working conditions, tiopronin is determined over the 1-400 microM range (150 microliters per injection, n = 10, r = 0.9994) with a detection limit of 0.34 microM and an RSD (n = 10) less than 2% at 20 and 50 microM. The proposed method, combining the advantages of speed and sensitivity, was applied to the routine determination of tiopronin in a pharmaceutical preparation.

Review: HPLC determination of fumonisin mycotoxins.

An overview of liquid chromatographic methods, mainly employing fluorescence detection together with sample pre-treatment methods, is presented for the determination of the toxic group of fumonisin mycotoxins in various matrices

HPLC on chiralcel OJ-R for enantiomer separation and analysis of ketoprofen, from horse plasma, as the 9-aminophenanthrene derivative.

Racemic ketoprofen is a non‐steroidal anti‐inflammatory drug used to treat musculoskeletal and colic conditions in horses. The enantioselective chiral inversion of ketoprofen administered to horses has been studied by use of cellulose tris(4‐methylbenzoate), also known as Chiralcel OJ‐R, as chiral stationary phase; acetonitrile − 0·02 m perchlorate buffer (pH 2·0) ‐ methanol, 60:15:25 (v/v/v) was used as mobile phase. Before chromatography, to effect adequate chiral interaction with the chiral stationary phase ketoprofen was derivatized with 9‐aminophenanthrene, under acid conditions, after solid‐phase (C18) extraction and then liquid–liquid extraction, to ensure effective removal of endogenous plasma materials. The 9‐aminophenanthrene derivative of S‐ibuprofen was used as internal standard. The enantiomers of ketoprofen were separated to baseline (Rs = 6·44, α = 1·76) within a short analysis time.

Enantiomeric separation of some piperidine-2,6-dione drugs on tolylcellulose by liquid chromatography.

The direct liquid Chromatographic resolution of a group of drugs, all having a piperidine-2,6-dione structure in common was investigated using a cellulose-based chiral stationary phase. The experimental tris(4-methylbenzoate) cellulose column (Bio-Rad RSL, Belgium) has the polymeric layer covalently bonded onto an aminopropylated silica support. Reversed phase as well as normal phase conditions were applied without deterioration of the column. Aminoglutethimide and glutethimide were easily resolved using methanol-water mixtures as mobile phase. Acetylaminoglutethimide, the major metabolite of aminoglutethimide, was separated from the parent drug but its enantiomers were not completely resolved. Thalidomide enantiomers were at best resolved under normal phase conditions with n-hexane as the major constituent of the mobile phase. No chiral interaction on this column was noticed for 3-phenylacetylaminopiperidine-2,6-dione.

Reversed-phase high-performance liquid chromatography of thiol—bimane derivatives

Abstract Fluorescent labelling of thiols with monobromobimane followed by RP-18 reversed-phase HPLC with aqueous acetic acid/acetone mixtures and fluorescence detection (λ(ex) = 380 nm;λ(em) = 470 nm) allows their selective and sensitive identification in various preparations.