TY - JOUR
T1 - Hair analysis for illicit drugs by using capillary zone electrophoresis-electrospray ionization-ion trap mass spectrometry
AU - Gottardo, Rossella
AU - Bortolotti, Federica
AU - De Paoli, Giorgia
AU - Pascali, Jennifer Paola
AU - Mikšík, Ivan
AU - Tagliaro, Franco
PY - 2007
Y1 - 2007
N2 - In forensic toxicology, hair analysis has become a well established analytical strategy to investigate retrospectively drug abuse histories. In this field, gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry are currently used, often after preliminary screening with immunoassays. However, on the basis of previous applications to pharmaceutical analysis, capillary zone electrophoresis coupled to ion trap mass spectrometry looks also highly promising. The purpose of the present work was the development of a simple and rapid CZE-MS method for sensitive and quantitative determination of the main drugs of abuse and their metabolites (namely, 6-monoacetylmorphine, morphine. amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethampthetamine (MDMA), benzoylecgonine, ephedrine and cocaine) in human hair. Hair samples (100 mg) were washed, cut and incubated overnight in 0.1 M HCl at 45 C, then neutralized with NaOH and extracted by a liquid-liquid extraction method. CZE separations were carried out in a 100 cm x 75 mu m (I.D.) uncoated fused silica capillary. The separation buffer was composed of 25 mM ammonium formate, pH 9.5; the separation voltage was 15 kV. Electrokinetic injections were performed at 7 kV for 30 s under field amplified sample stacking conditions. ESI-ion trap MS detection was performed in the ESI positive ionization mode using the following conditions: capillary voltage 4 kV, nebulizer gas (nitrogen) pressure 3 psi, source temperature 150 degrees C and drying gas (nitrogen) flow rate: 81/min. A sheath liquid, composed of isopropanol-water (50:50, v/v) with 0.5% formic acid, was delivered at a flow rate of 4 mu l/nun. The ion trap MS operated in a selected ion monitoring mode (SIM) of positive molecular ions for each drug/metabolite. Collision induced fragmentation was also possible. Nalorphine was used as internal standard. Under the described conditions, the separation of all compounds, except amphetamine/methamphetamine, MDA/MDMA and morphine/6-MAM was achieved in 20 min, with limits of detection lower than the most severe cut-offs adopted in hair analysis (i.e. 0.1 ng/mg). Linearity was assessed within drug concentration ranges from 0.025 to 5 ng of each analyte/mg of hair. Analytical precision was fairly acceptable with RSD's <= 3.06% for migration times and <= 22.47% for areas in real samples, in both intra-day and day-to-day experiments. On these grounds, the described method can be proposed for rapid, selective and accurate toxicological hair analysis for both clinical and forensic purposes. (c) 2007 Elsevier B.V. All rights reserved.
AB - In forensic toxicology, hair analysis has become a well established analytical strategy to investigate retrospectively drug abuse histories. In this field, gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry are currently used, often after preliminary screening with immunoassays. However, on the basis of previous applications to pharmaceutical analysis, capillary zone electrophoresis coupled to ion trap mass spectrometry looks also highly promising. The purpose of the present work was the development of a simple and rapid CZE-MS method for sensitive and quantitative determination of the main drugs of abuse and their metabolites (namely, 6-monoacetylmorphine, morphine. amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethampthetamine (MDMA), benzoylecgonine, ephedrine and cocaine) in human hair. Hair samples (100 mg) were washed, cut and incubated overnight in 0.1 M HCl at 45 C, then neutralized with NaOH and extracted by a liquid-liquid extraction method. CZE separations were carried out in a 100 cm x 75 mu m (I.D.) uncoated fused silica capillary. The separation buffer was composed of 25 mM ammonium formate, pH 9.5; the separation voltage was 15 kV. Electrokinetic injections were performed at 7 kV for 30 s under field amplified sample stacking conditions. ESI-ion trap MS detection was performed in the ESI positive ionization mode using the following conditions: capillary voltage 4 kV, nebulizer gas (nitrogen) pressure 3 psi, source temperature 150 degrees C and drying gas (nitrogen) flow rate: 81/min. A sheath liquid, composed of isopropanol-water (50:50, v/v) with 0.5% formic acid, was delivered at a flow rate of 4 mu l/nun. The ion trap MS operated in a selected ion monitoring mode (SIM) of positive molecular ions for each drug/metabolite. Collision induced fragmentation was also possible. Nalorphine was used as internal standard. Under the described conditions, the separation of all compounds, except amphetamine/methamphetamine, MDA/MDMA and morphine/6-MAM was achieved in 20 min, with limits of detection lower than the most severe cut-offs adopted in hair analysis (i.e. 0.1 ng/mg). Linearity was assessed within drug concentration ranges from 0.025 to 5 ng of each analyte/mg of hair. Analytical precision was fairly acceptable with RSD's <= 3.06% for migration times and <= 22.47% for areas in real samples, in both intra-day and day-to-day experiments. On these grounds, the described method can be proposed for rapid, selective and accurate toxicological hair analysis for both clinical and forensic purposes. (c) 2007 Elsevier B.V. All rights reserved.
U2 - 10.1016/j.chroma.2007.01.011
DO - 10.1016/j.chroma.2007.01.011
M3 - Article
SN - 0021-9673
VL - 1159
SP - 185
EP - 189
JO - Journal of Chromatography. A
JF - Journal of Chromatography. A
IS - 1-2
ER -