title: Determination of estrogenic compounds in milk and yogurt samples by hollow-fibre liquid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry.
abstract: An environmentally friendly method based on hollow-fibre liquid-phase microextraction (HF-LPME) was developed for the extraction of selected estrogenic compounds (i.e. four natural sexual hormones: estrone, 17β-estradiol, 17α-estradiol and estriol; two exoestrogens: 17α-ethynylestradiol and 2-methoxyestradiol; two synthetic stilbenes: dienestrol and hexestrol; and five resorcylic acid lactones: zearalenone, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol), from whole cow and semi-skimmed goat milk and whole natural yogurt. After the optimization of the sample preparation procedure, spiked extracts were derivatized to their trimethylsilyl products using N,O-bis(trimethylsilyl)trifluoroacetamide reagent and then analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Once optimum extraction conditions were established (protein precipitation with acetonitrile, extraction and the back-extraction in acetonitrile following the HF-LPME procedure), the method was validated and the calibration range, precision and accuracy were studied. The RSD values for the intra- and inter-day precision of the peak areas were in the range 0.65-9.69 and 1.00-11.47 %, respectively. The determination coefficients were higher than 0.991 for method calibration curves while LOD and LOQ values were between 0.06-2.55 and 0.16-6.11 μg/L for whole cow milk, 0.04-1.70 and 0.11-4.86 μg/L for semi-skimmed goat milk and 0.07-3.73 and 0.23-9.81 μg/L for natural yogurt, respectively. Finally, the accuracy and precision of the method were evaluated, obtaining a value in the range 84 81-119 % and RSD values lower than 20 % in all cases.
authors.affiliation: Institute of Chemical Methodologies, Italian National Research Council-C.N.R., Area della Ricerca di Roma I, Via Salaria Km 29,300, 00015, Monterotondo, Roma, Italy.|Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n°, 38206, La Laguna, Tenerife, Spain.
authors.forename: Giovanni
authors.initials: G
authors.lastname: D'Orazio
authors.affiliation: Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n°, 38206, La Laguna, Tenerife, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Hernández-Borges
authors.affiliation: Instituto Universitario de BioOrgánica Antonio González, Universidad de La Laguna (ULL), Avda. Astrofísico Fco. Sánchez, 2, 38206, La Laguna, Tenerife, Spain.
authors.forename: Antonio Vicente
authors.initials: AV
authors.lastname: Herrera-Herrera
authors.affiliation: Institute of Chemical Methodologies, Italian National Research Council-C.N.R., Area della Ricerca di Roma I, Via Salaria Km 29,300, 00015, Monterotondo, Roma, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Fanali
authors.affiliation: Departamento de Química, Unidad Departamental de Química Analítica, Facultad de Ciencias, Universidad de La Laguna (ULL), Avenida Astrofísico Francisco Sánchez s/n°, 38206, La Laguna, Tenerife, Spain. mrguez@ull.edu.es.
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Rodríguez-Delgado
mesh_terms: D000818:Animals; D002417:Cattle; D004967:Estrogens / Q000032:analysis* / Q000302:isolation & purification; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006041:Goats; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D008892:Milk / Q000737:chemistry*; D015014:Yogurt / Q000032:analysis*
chemical_list: D004967:Estrogens
keywords: Estrogens; Gas chromatography-triple quadrupole mass spectrometry; Hollow-fibre liquid-phase microextraction; Milk; Yogurt