title: Application of solid phase microextraction to the determination of strychnine in blood.
abstract: A simple and rapid method based on solid phase microextraction (SPME) via direct immersion followed by gas chromatography coupled with electron impact ionization/mass spectrometry (GC/EI-MS) was developed for the determination of strychnine in blood. Papaverine was used as internal standard (I.S.). Two types of fibre coating were tested, 100 microm polydimethylsiloxane and 65 microm Carbowax/Divinylbenzene, the latter giving higher recoveries of the compound. The main factors affecting the SPME process, such as sample dilution (1:10), adsorption and desorption times (20 and 10 min, respectively), carry-over effect (not observed), pH and salt addition (no modifications on pH or salt concentration) were optimized. The procedure was validated in terms of linearity (r(2)=0.9992 for concentrations ranging from 0.10 to 5.00 microg/mL), intra and interday precision (0.93 and 4.62%, respectively at 0.50 microg/mL; 3.33 and 8.06%, respectively at 2.50 microg/mL), sensitivity (6.83 and 8.91 ng/mL for LOD and LOQ, respectively) and extraction recovery (0.54 and 0.39% at 0.50 and 2.50 microg/mL, respectively). The developed procedure was found suitable for forensic investigations and was considered a good alternative to the liquid-liquid extraction methods normally used for the determination of this compound in biological media.
authors.affiliation: Instituto Nacional de Medicina Legal, Delegação de Coimbra, Largo da Sé Nova, 3000-213 Coimbra, Portugal. mjbarroso@iol.pt
authors.forename: M
authors.initials: M
authors.lastname: Barroso
authors.forename: E
authors.initials: E
authors.lastname: Gallardo
authors.forename: C
authors.initials: C
authors.lastname: Margalho
authors.forename: S
authors.initials: S
authors.lastname: Avila
authors.forename: E P
authors.initials: EP
authors.lastname: Marques
authors.forename: D N
authors.initials: DN
authors.lastname: Vieira
authors.forename: M
authors.initials: M
authors.lastname: López-Rivadulla
mesh_terms: D000327:Adsorption; D002849:Chromatography, Gas; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008832:Microchemistry; D009994:Osmolar Concentration; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013331:Strychnine / Q000097:blood*; D013599:Systole
chemical_list: D013331:Strychnine