Optimization of a simple method for the chiral separation of phenethylamines of forensic interest based on cyclodextrin complexation capillary electrophoresis and its preliminary application to the analysis of human urine and hair

• Published in: Forensic science international 1997-09, Vol.89 (1), p.33-46
• Main Authors: Scarcella, D, Tagliaro, F, Turrina, S, Manetto, G, Nakahara, Y, Smith, F.P, Marigo, M
• Format: Article
• Language: English
• Subjects: Amphetamine; Amphetamines; Analysis; beta-Cyclodextrins; Biological and medical sciences; Buffers; Capillary Electrophoresis; Chromatography; Cyclodextrins; Drug abuse; Drugs; Electric potential; Electrophoresis; Electrophoresis, Capillary - methods; Enantiomers; Ephedrine; Forensic Medicine - methods; Forensic science; Fused silica; Hair; Hair - chemistry; Human wastes; Humans; Hydrogen-Ion Concentration; Laboratories; Liquid-liquid extraction; Medical sciences; Metamphetamine; Methamphetamine; Methods; Optimization; Pharmacology. Drug treatments; Phenethylamines - analysis; Phenethylamines - urine; Reagents; Reproducibility of Results; Respiratory system; Sensitivity analysis; Sensitivity and Specificity; Silica; Substance Abuse Detection - methods; Substance-Related Disorders - diagnosis; Urine; Voltage; β-Cyclodextrin
• ISSN: 0379-0738; 1872-6283
• DOI: 10.1016/S0379-0738(97)00108-4

Because of the forensic importance of the chiral analysis of amphetamine and other phenethylamines for investigating their synthetic pathways and the metabolic patterns of these compounds, a capillary electrophoresis method has been developed based on the chiral selectivity of β-cyclodextrin. The influence of different experimental conditions, such as cyclodextrin nature and concentration, voltage, temperature and buffer concentration and pH, on analytical performance has been studied. The optimized analytical conditions are: capillary: bare fused silica, 50 μm I.D., 40 cm effective length; buffer: 150 mM phosphate pH=2.5, 15 mM β-cyclodextrin; voltage: 10 kV; temperature: 17.5°C; detection: UV absorption at 200 nm wavelength. Under these conditions, amphetamine, methamphetamine and ephedrine have been easily separated, with baseline resolution of the respective enantiomers. Sensitivity was better than 300 ng per ml. The average precision of migration times of the three analytes was good with RSD=0.45% and 0.58% in intra-day and day-to-day tests, respectively. Reproducibility of peak heights was also good, with RSD=2.51% and 3.14% in intra-day and day-to-day tests, respectively. The preliminary analysis of amphetamine in human urine and hair samples, subjected to a simple work-up procedure based on liquid–liquid extraction, showed clean blank electropherograms, excellent chiral resolution and sensitivity, suitable for the analysis of real samples from amphetamine users.