title: Pre-column fluorescence derivatization using leucine-coumarnylamide for HPLC determination of mono- and dicarboxylic acids in plasma.
abstract: A sensitive HPLC assay utilising a simple fluorescence pre-column labelling technique was developed for plasma level monitoring of different types of mono- and dicarboxylic acids. Carboxylic acids form mixed anhydrides with ethyl chloroformate in the presence of triethylamine; the mixed anhydrides further react with L-leucine-4-methyl-7-coumarinylamide, forming highly fluorescent and stable amides. Drugs with no chromophore (azelaic acid, and its longer carbon chain analogues) or week UV absorption (artelinic acid, enalaprilat) were used as model compounds. The plasma samples were extracted using ion exchange solid phase cartridges. The separation was performed on an Axxiom C18 (5 microns, 4.6 x 250 mm) column. The detector wavelengths were set at 330 nm for excitation and 390 nm for emission.
authors.affiliation: Pharmacokinetic and Metabolism Laboratory, CHINOIN Pharmaceutical and Chemical Works Co. Ltd., Budapest, Hungary.
authors.forename: F
authors.initials: F
authors.lastname: Lévai
authors.forename: C M
authors.initials: CM
authors.lastname: Liu
authors.forename: M M
authors.initials: MM
authors.lastname: Tse
authors.forename: E T
authors.initials: ET
authors.lastname: Lin
mesh_terms: D000818:Animals; D002264:Carboxylic Acids / Q000097:blood* / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003998:Dicarboxylic Acids / Q000097:blood* / Q000737:chemistry*; D005453:Fluorescence; D007930:Leucine; D010867:Pimelic Acids / Q000097:blood / Q000737:chemistry; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002264:Carboxylic Acids; D003998:Dicarboxylic Acids; D010867:Pimelic Acids; C010038:azelaic acid; D007930:Leucine