title: Application of bar adsorptive microextraction (BAμE) for anti-doping control screening of anabolic steroids in urine matrices.
abstract: This study proposes a new analytical methodology for the determination of trace levels of testosterone (T) and epitestosterone (E) in urine matrices using bar adsorptive microextraction combined with liquid desorption followed by high-performance liquid chromatography with diode array detection (BAμE-LD/HPLC-DAD). The comparison of different sorbent coatings (five activated carbons, one styrene-divinylbenzene, two modified pyrrolidone, one ciano and one n-vinylpyrrolidone polymers) through BAμE showed that the latter phase presented much higher selectivity and capacity offering multiple mechanisms of interaction. Assays using this phase were performed on 25mL of water samples spiked at the 8.0μg/L level, yielded average recoveries of 92.1 and 93.4% for T and E, respectively, under optimized experimental conditions; BAμE (n-vinylpyrrolidone): 16h (1000rpm), pH 5.5; LD: acetonitrile, 30min under sonication treatment. From the developed analytical methodology, suitable detection limits were achieved (0.4μg/L) and good linear dynamic ranges (1.4-16.0μg/L) with remarkable determination coefficients (r(2)>0.9978). By using the standard addition methodology, the application of the present analytical approach on urine samples revealed good sensitivity. The proposed method, which operated under the floating sampling technology, proved to be a suitable sorption-based static microextraction alternative for screening T, E and the T/E ratio in urine samples for doping control purposes. The methodology showed to be easy to implement, demonstrating good reproducibility, sensitivity and robustness, allowing the possibility to choose the most selective sorbent coating according to the compounds of interest.
authors.affiliation: University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department, Centre of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal.
authors.forename: S M
authors.initials: SM
authors.lastname: Ahmad
authors.affiliation: University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department, Centre of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Almeida
authors.affiliation: University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department, Centre of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal. Electronic address: ndneng@fc.ul.pt.
authors.forename: N R
authors.initials: NR
authors.lastname: Neng
authors.affiliation: University of Lisbon, Faculty of Sciences, Chemistry and Biochemistry Department, Centre of Chemistry and Biochemistry, Campo Grande Ed. C8, 1749-016 Lisbon, Portugal. Electronic address: nogueira@fc.ul.pt.
authors.forename: J M F
authors.initials: JM
authors.lastname: Nogueira
mesh_terms: D000328:Adult; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004300:Doping in Sports; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004845:Epitestosterone / Q000737:chemistry / Q000302:isolation & purification / Q000652:urine*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D015203:Reproducibility of Results; D013739:Testosterone / Q000737:chemistry / Q000302:isolation & purification / Q000652:urine*
chemical_list: D013739:Testosterone; D004845:Epitestosterone
keywords: BAμE.; Epitestosterone; Floating sampling technology; Testosterone; Urine matrices