Determination of illicit drugs in horse urine using carboxylic multi-walled carbon nanotubes as immobilized stationary phase in capillary electrochromatography

PATRICIA W. STEGE; ALICIA V. LAPIERRE; LUIS D. MARTINEZ; LORENA L. SOMBRA

Sevilla (España)

Congreso; 15 Latin American Symposium on Biotechnology, Biomedical, Biopharmaceutical and Industrial Applications of Capillary Electrophoresis and Microchip Technology.; 2009

<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-1610611985 1073750139 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-fareast-font-family:Calibri; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US;} p.MsoBodyTextIndent, li.MsoBodyTextIndent, div.MsoBodyTextIndent {mso-style-priority:99; mso-style-link:"Sangría de texto normal Car"; margin-top:0cm; margin-right:0cm; margin-bottom:6.0pt; margin-left:14.15pt; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-fareast-font-family:Calibri; mso-bidi-font-family:"Times New Roman"; mso-fareast-language:EN-US;} span.SangradetextonormalCar {mso-style-name:"Sangría de texto normal Car"; mso-style-priority:99; mso-style-unhide:no; mso-style-locked:yes; mso-style-link:"Sangría de texto normal"; mso-ansi-font-size:11.0pt; mso-bidi-font-size:11.0pt; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; mso-ascii-font-family:Calibri; mso-fareast-font-family:Calibri; mso-hansi-font-family:Calibri;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Administration studies of abused drugs (cocaine, morphine, caffeine, theobromine, ephedrine, strychnine and piroxicam) in horses were developed using capillary electrochromatography (CEC) with a stationary phase of carbon nanotubes (c-MWNTs) immobilized into a fused-silica capillary. Doping in horseracing is a problem currently ongoing. The term doping was defined as the administration of illegal drugs to animals in competition with the intention of altering its physical performance, either positively or negatively. These kinds of substances are the ones with the highest potential to affect racing performance and have no generally accepted therapeutic use. In recent years there has been great progress in the sensitivity of the analytical methods of control. This CEC method allows recognition of the most used abused drugs used in racehorses. Some analytical conditions were taken into account to completely separate in the same run the 7 drugs analyzed. Carboxylated multi-wall carbon nanotubes (c-MWNTs) have been immobilized into a fused-silica capillary to form a stationary phase for CEC. The c-MWNTs were successfully incorporated after the silanization and coupling with glutaraldehyde of the inner surface of the capillary. With the purpose of enrichment and sample clean-up we used a simple method as liquid-liquid extraction. All the drugs in study were basic, so the pH of the urines samples was adjusted into the alkaline range prior to LLE. A mixture of Clorophormo/Methanol (90:10) was used as the extract phase. Then the extract (organic phase) was evaporated to dryness and the residue was reconstituted with 1 ml of water. We have investigated the electrophoretic features of the novel c-MWNT immobilized fused-silica capillary by covalent modification of the inner surface of the capillary. Good run-to-run, day-to-day and capillary-to-capillary reproducibility have been obtained. Results indicated good capillary efficiencies and improved electrophoretic separation. We can conclude that the applicability for monitoring and quantification of abused drugs used in racehorses for this method has been demonstrated.   - Veterinary Regulations. Federation Equestre International, 7th edition. 1 January, Lausanne. Switzwerland 1993. -Valcárcel, M.;  Cárdenas, S.; Simonet, B.M.; Moliner-Martínez, Y.; Lucena, R. Trends Anal. Chem. 2008, 27, 34-43. -Sombra, L.; Moliner-Martínez,Y.; Cárdenas, S.; Valcárcel, M.; Electrophoresis 2008, 29, 3850–3857.