On-Line Derivatization into Precolumns for the Determination of Drugs by Liquid Chromatography and Column Switching:  Determination of Amphetamines in Urine

Abstract

A chromatographic system for the on-line derivatization of drugs using column switching is described. The system uses a 20 mm x 2.1 mm i.d. precolumn packed with a unmodified ODS stationary phase. This column is used for sample cleanup and enrichment of the analytes. Next, the trapped analytes are derivatized by injection of the derivatization reagent into the precolumn. Finally, the derivatives are transferred to the analytical column for their separation under reversed-phase conditions. The influence of several parameters such as the reaction time, the amount of derivatization reagents, or the system design has been studied some amphetamines as model compounds and three derivatization reagents: sodium 1, 2-naphthoquinone-4-sulfonate, o-phthaldialdehyde, and 9-fluorenylmethyl chloroformate. The potential of the described approach is illustrated by determining amphetamine and methamphetamine in untreated urine at ambient temperature.

Rapid fluorimetric assay for primary amine groups in water samples

“…Analyte enrichment Based on previous experiments with different types of amines, Bond Elut C 18 cartridges were selected for preconcentration of the analytes [10,12,19]. The amine con-919 Fig.…”

“…Also, the extract can be injected in a liquid chromatograph for its separation and detection. The potential of our methodology has been illustrated for quantifying several amino-compound of interest in clinical or pharmaceutical analysis [11,12,13,14,15,16]. This methodology improves the analytical characteristics of the pre-column solution derivatization procedure.…”

On-Line Coupling of Solid Phase Extraction Sample Processing with High-Performance Liquid Chromatography

“…Herráez-Hernández et al 44,45 proposed a very simple procedure for on-line derivatization of drugs based on the employment of precolumns packed with conventional C 18 materials. The precolumn was used to purify the sample and concentrated the analytes and, next, to retain the derivatives (the reagent mixture was injected into the precolumn immediately after sample cleaning).…”

Determination of amphetamine and its metabolite p‐hydroxyamphetamine in rat urine by reversed‐phase high‐performance liquid chromatography after dabsyl derivatization

“…1,2-naphthoquinone-4-sulfonate was also assayed (Herráez-Hernández et al, 1996) as well as 3-mercaptopropionic acid (Bowyer et al, 1995). Some drawbacks of these agents or restrictions in required equipment for detection of the respective derivatives impelled us to search for a different derivatization procedure, using 4-dimethylaminoazobenzene-4'-sulfonyl chloride (dabsyl chloride).…”