SUMMARY

The suitability of isotachophoresis for the determination of quinine in different samples was investigated. The operational conditions were 0.01 M potassium-mor-pholinoethanesulphonic acid (MES) (pH 6.0) with 0.05 % Mowiol as the leading electrolyte and‘ca. 0.005 M creatinine-MES as the terminating electrolyte. The anal-yses were carried out at 25 PA in a 0.2 mm I.D. PTFE capillary with UV and con-ductivity detection. Quinine-containing beverages were degassed by sonification and directly in-jected. The limit of detection was 5 mg/l with a 4 ~1 injection volume. The allowed concentrations could be determined with sufficient accuracy. Analgesic preparations were dissolved in a solution of 5. lop3 M MES with sonification. The quinine levels found agreed well with the declared values. The other constituents of the pharma-ceuticals did not interfere with the analysis. Urine samples from volunteers were analysed after consumption of tonic. The samples were extracted with dichloromethane-isopropanol (95:5), vortexed, centrifuged, evaporated to dryness, the residue dissolved in 5. 10m3 M MES and analysed. At a concentration factor of 33, the limit of detection was cca. 60 pg in 48-h urine: 2-15 % of the quinine consumed was excreted as the parent compound in the first 48 h after consumption. The combination of the extraction procedure and the operational system makes the method suitable for the determination of a number of other alkaloids in physiological samples