title: Speeding up the process urine sample pre-treatment: some perspectives on the use of microwave assisted extraction in the anti-doping field.
abstract: In this contribution we described a fast and efficient method for the liquid/liquid extraction from human urine of different classes of drugs, included in the list of prohibited substances published every year by the World Anti-doping Agency, using microwave irradiation. Liquid/liquid extraction was conducted in a temperature controlled single beam microwave oven equipped with an extraction unit and closed vessels. The effects of microwave power and time on the liquid/liquid extraction process were investigated utilizing different organic solvents. The optimum power was found to be 600W (generating a temperature of 70 degrees C) with an incubation time of 30-60s for the most thermolable constituents such as triamcinolone, prednisolone, chlorthiazide, chlorthalidone, epi-trembolone and oxandrolone, and 1020W (generating a temperature of 150 degrees C) with an incubation time of 30-60s for the other compounds considered in this study. The effectiveness of this approach was evaluated by GC-MS (anabolic steroids, beta2-agonists and narcotics) and by LC-MS/MS (diuretics, glucocorticoids and beta-blockers) analyzing more than 20 different urine samples spiked with the compounds considered in this study. The results showed that the effect of microwave irradiation on the liquid/liquid extraction process was very remarkable: the total sample preparation time can be shortened by 9min compared to the traditional method (30-60s instead of 10min); furthermore, a significant increase in the recovery was recorded for specific compounds such as terbutaline and several diuretics. In addition to the above the repeatability of the extraction recoveries, the limits of detection and the matrix interferences were comparable with the reference methods, presently accredited under the ISO17025, followed by the World Anti-doping Agency accredited anti-doping laboratory of Rome.
authors.affiliation: Laboratorio Antidoping, Federazione Medico Sportiva Italiana, Largo Giulio Onesti, Rome, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Mazzarino
authors.forename: Sara
authors.initials: S
authors.lastname: Riggi
authors.forename: Xavier
authors.initials: X
authors.lastname: de la Torre
authors.forename: Francesco
authors.initials: F
authors.lastname: Botrè
mesh_terms: D002623:Chemistry Techniques, Analytical; D004300:Doping in Sports; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006358:Hot Temperature; D006801:Humans; D057230:Limit of Detection; D008872:Microwaves; D009930:Organic Chemicals / Q000737:chemistry; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D015813:Substance Abuse Detection / Q000295:instrumentation* / Q000379:methods*; D013997:Time Factors; D016482:Urinalysis / Q000379:methods*
chemical_list: D009930:Organic Chemicals; D012997:Solvents