Reaction of some sympathomimetic amines with sodium 1,2-naphthoquinone-4-sulphonate

Amphetamine and methamphetamine determination in urine by reversed-phase high-performance liquid chromatography with sodium 1,2-naphthoquinone 4-sulfonate as derivatizing agent and solid-phase extraction for sample clean-up

A rapid method is described for the identification and determination of amphetamine and methamphetamine in human urine samples by liquid chromatography with UV-Vis detection. The samples were transferred onto a C18 solid-phase extraction column and chromatographed on a Hypersil ODS RP C18, 5 microns (250 x 4 mm I.D.) with an acetonitrile-water elution gradient containing propylamine. Under these conditions, the amines are eluted with a short retention time. The procedure has been applied to the determination of amphetamine and methamphetamine in the range 0.3-4.0 micrograms/ml in spiked urine samples. The detection limits at 280 nm were 4 and 2 ng/ml for amphetamine and methamphetamine, respectively. The intra-day and inter-day precision and accuracy of the method were studied.

Improved amphetamine and methamphetamine determination in urine by normal-phase high-performance liquid chromatography with sodium 1,2-naphthoquinone 4-sulphonate as derivatizing agent and solid-phase extraction for sample clean-up

Solid-phase extraction techniques were evaluated for the treatment of urine samples in the analysis of amphetamine and methamphetamine by normal-phase high-performance liquid chromatography with 1,2-naphthoquinone 4-sulphonate. Six different packing materials were tested, and the results obtained are compared with those obtained in a classical liquid-liquid extraction with n-hexane. Different clean-up eluents and the influence of pH of urine have been tested. The intra-day and inter-day precision, the accuracy of the method and the addition of beta-phenylethylamine as internal standard were also studied.

Simultaneous identification of amphetamine and its derivatives in urine using HPLC-UV

An HPLC-UV method for the simultaneous identification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA) in urine is described. It includes a rapid extraction procedure of the 4 analogs from urine using Extrelut 3 columns, derivatization with sodium 1,2-naphthoquinone-4-sulphonate (NQS) to obtain highly chromophoric UV-VIS derivatives, and a final HPLC analysis using an ion-pair reversed-phase technique with eluent monitoring at 480 nm. Structural characterization of the derivatives obtained by mass spectrometry is reported. Recoveries of the amphetamines were in the range 80-85% at concentrations of 300 ng/ml. Practical detection limits were 40-60 ng/ml (S/N ratio = 10) for all derivatives. The chromatographic peaks of the NQS derivatized amphetamines are fairly narrow and well resolved. The method is simple, rapid, quite sensitive, and specific for convenient confirmation of preliminary positive results obtained with immunoassays.

An investigation of high-performance liquid chromatographic methods for the analysis of amphetamines

Three pre-column derivatization reagents, namely o-phthalaldehyde, 4-chloro-7-nitro-benz-2,1,3-oxadiazole, sodium naphthaquinone-4-sulphonate and two ion-pair reagents, namely, naphthalene-2-sulphonate and sodium dodecylsulphate have been investigated for their suitability for the qualitative and quantitative analysis of urine and plasma samples containing amphetamines. The derivatization method employing sodium naphthaquinone-4-sulphonate was found to be selective and sufficiently sensitive for the routine determination of amphetamine and methylamphetamine in urine and plasma samples at the ng/ml level.