{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T23:59:59Z","timestamp":1789603199710,"version":"build-2803163510"},"reference-count":42,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2019,11,4]],"date-time":"2019-11-04T00:00:00Z","timestamp":1572825600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"name":"National Commission of Sport Mexico"},{"name":"School of Higher Studies (FES) Cuautitl\u00e1n-UNAM"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,4,30]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Clenbuterol (4-amino-\u03b1-[(tert-butylamino)methyl]-3,5-dichlorobenzylalcohol) is a \u03b22-adrenergic agonist. The consumption of meat contaminated with clenbuterol can lead to increased heart rate, blood pressure, anxiety, palpitations and skeletal muscle tremors. Several analytical methods have been developed to identify and quantify clenbuterol in different biological matrices. In this report, we have developed a specific and sensitive analytical method for quantifying clenbuterol and performed an in-depth enantiomeric analysis in bovine urine. The method was evaluated in accordance with international guidelines, and we used an isotopically labeled analog as an internal standard. The extraction efficiency for clenbuterol in bovine urine was &amp;gt;\u200998%, the limit of detection was 0.05\u00a0ng\/mL and the limit of quantification was 0.10\u00a0ng\/mL. Our assay showed high specificity, no carryover was observed and the assay was linear in the range 0.10\u20138.0\u00a0ng\/mL. Fifteen bovine urine samples were analyzed (containing clenbuterol), and an enantiomeric analysis was performed. The clenbuterol concentration range was 0.10\u201310.56\u00a0ng\/mL across these samples. The levorotatory enantiomer was detected at greater concentrations than the dextrorotatory enantiomer, the ratio being 1.7\u00a0\u00b1\u00a00.6 (n\u00a0=\u00a015), and a statistical difference was observed (P\u00a0&amp;lt;\u00a00.05) using the Wilcoxon test.<\/jats:p>","DOI":"10.1093\/jat\/bkz087","type":"journal-article","created":{"date-parts":[[2019,9,10]],"date-time":"2019-09-10T19:24:46Z","timestamp":1568143486000},"page":"237-244","source":"Crossref","is-referenced-by-count":9,"title":["Quantification and Stereochemical Composition of R-(\u2212) and S-(+)-Clenbuterol Enantiomers in Bovine Urine by Liquid Chromatography\u2013Tandem Mass Spectrometry"],"prefix":"10.1093","volume":"44","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2934-8698","authenticated-orcid":false,"given":"Benjam\u00edn","family":"Velasco-Bejarano","sequence":"first","affiliation":[{"name":"Secci\u00f3n de Qu\u00edmica Org\u00e1nica, Departamento de Ciencias Qu\u00edmicas, Facultad de Estudios Superiores Cuautitl\u00e1n, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Av 1 de mayo S\/N, Col. Sta Mar\u00eda las Torres, Cuautitl\u00e1n Izcalli, CP54740, Estate of M\u00e9xico, Mexico"},{"name":"Laboratorio Nacional de Prevenci\u00f3n y Control del Dopaje-CONADE, Camino a Sta Teresa 482, Col. Pe\u00f1a Pobre, Alcald\u00eda Tlalpan, CP14060, Mexico city, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jahir","family":"Bautista","sequence":"first","affiliation":[{"name":"Laboratorio Nacional de Prevenci\u00f3n y Control del Dopaje-CONADE, Camino a Sta Teresa 482, Col. Pe\u00f1a Pobre, Alcald\u00eda Tlalpan, CP14060, Mexico city, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martha E","family":"Rodr\u00edguez","sequence":"first","affiliation":[{"name":"Laboratorio Nacional de Prevenci\u00f3n y Control del Dopaje-CONADE, Camino a Sta Teresa 482, Col. Pe\u00f1a Pobre, Alcald\u00eda Tlalpan, CP14060, Mexico city, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raquel","family":"L\u00f3pez-Arellano","sequence":"first","affiliation":[{"name":"Laboratorio de Desarrollo Farmac\u00e9utico-LEDEFAR, Facultad de Estudios Superiores Cuautitl\u00e1n, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Carretera Cuautitl\u00e1n-Teoloyucan km 2.5, San Sebasti\u00e1n Xhala CP 54714, Estate of M\u00e9xico, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Roberto","family":"Arregu\u00edn-Espinosa","sequence":"first","affiliation":[{"name":"Departamento de Qu\u00edmica de Biomacromol\u00e9culas, Instituto de Qu\u00edmica, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Circuito Exterior, Ciudad Universitaria, Alcald\u00eda Coyoac\u00e1n, CP04510, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ricardo Velasco","family":"Carrillo","sequence":"first","affiliation":[{"name":"Divisi\u00f3n de Estudios de Posgrado e Investigaci\u00f3n del, Tecnol\u00f3gico Nacional de M\u00e9xico\/Divisi\u00f3n de Estudios de Posgrado e Investigaci\u00f3n del, Instituto Tecnol\u00f3gico de Altamira, Carretera Tampico-Mante Km 24.5. 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