Liquid chromatography on an amide stationary phase with post-column derivatization and fluorimetric detection for the determination of streptomycin and dihydrostreptomycin in foods.
The separation of streptomycin and its derivative dihydrostreptomycin using ion-pair liquid chromatography is proposed. The method is based on the use of a new stationary phase based on a ligand with amide groups and the endcapping of trimethylsilyl which avoids the appearance of tailed peaks. The isocratic mobile phase consisted of a 6:94 (v/v) acetonitrile/10mM pentanesulfonic acid (pH 3.3) mixture at a flow-rate of 1mLmin(-1) and fluorescence detection involved a post-column derivatization reaction using beta-naphthoquinone-4-sulfonate. Linearity, precision, recovery and sensitivity were satisfactory. The procedure was applied to the analysis of the aminoglycoside antibiotics in different types of foods, as honey, milk, egg and liver. Extraction was carried out by acidic hydrolysis to release protein-bound antibiotics. Detection limits in the food samples are 7.5 and 15mugkg(-1) for streptomycin and dihydrostreptomycin, respectively.
Viñas
Pilar
P
Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia, Spain.
Balsalobre
Nuria
N
Hernández-Córdoba
Manuel
M