Quantification and enantiomeric distribution of clenbuterol in several bovine tissues using UHPLC-tandem mass spectrometry: Evaluation of a risk factor associated with meat contamination.

Clenbuterol (Clb) (4-amino-α-[(tert-butylamine) methyl]-3,5-dichlorobenzyl alcohol) is a sympathomimetic agent that exhibits ß2-agonist activity. It is applied as a bronchodilatory, tocolytic, and mucolytic agent and is authorized for clinical management in both human and veterinary therapeutics as a racemic mixture. However, its use is strictly prohibited in animals destined for food production in countries in the European Union and in the United States and Mexico, among many others. The R-(-) enantiomer in clenbuterol stimulates ß2-receptors, whereas the S-(+) enantiomer blocks the effect of ß1-receptors. The aims of this study were to develop a method for detecting and quantifying Clb and its enantiomeric distribution in several bovine tissues. The UHPLC-MS/MS method developed to quantify the target compound at trace levels in these tissues combines high sensitivity with good selectivity and short chromatographic run time. The tissue samples tested were found to contain racemic Clb in concentrations of 5-447 pg g-1 . The enantiomeric analysis of Clb showed that R-(-)-Clb is present at higher concentrations in some tissues, whereas S-(+)-Clb was detected in a ratio of 55/45 in the liver and heart tissues.

Detection of clenbuterol residues in beef sausages and its enantiomeric analysis using UHPLC-MS/MS: A risk of unintentional doping in sport field.

Clenbuterol (Clb) can be present in Mexico often but not all over the world in animal tissues and organs, therefore, potentially is derived from animal sources as well. The aims of this study were to develop and validate a method for detecting traces of clenbuterol in beef sausages. A calibration curve showed linearity in the range of 20-500 pg ml-1 . The limit of detection (LOD) and lower limit of quantification (LLOQ) were 5 and 10 pg g-1 , respectively. The analyte recovery was from 95.70% to 100.40% with an intraday relative standard deviation (RSD%) of 0.99%-2.10% and an interday RSD% of 0.54%-2.34%, R2 = 0.9998. The methodology developed was applied successfully in 15 samples of beef sausage, and 73.3% of the samples tested contained racemic clenbuterol in concentrations between 30 and 471 pg g-1 . The UHPLC-MS/MS method developed combines high sensitivity with good selectivity and short chromatographic run time. Additionally, the enantiomeric analysis of clenbuterol performed in beef sausages showed a 59% for R-(-)-Clb and 41% for S-(+)-Clb. The presence of clenbuterol in beef sausages could represent a risk of unintentional doping in sport field, because the clenbuterol is a banned substance included in the World Anti-Doping Agency's (WADA) list of prohibited substances.

Determination of clenbuterol at trace levels in raw gelatin powder and jellies using ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry.

Clenbuterol is present in animal tissues and organs and, therefore, potentially present in gelatin derived from animal sources. The objective of this study was to develop a method for identify an quantify traces of clenbuterol in gelatin and jellies. The clenbuterol calibration curve showed linearity in the range of 20-1000 pg mL-1. The detection and quantification limits were 5 pg g-1 and 10 pg g-1, respectively. The recovery of the analyte ranged from 93.4 to 98.7% with an intra-day RSD% (n = 4) of 1.25%-3.25%, and an inter-day RSD% (n = 12) of 0.5%-2.25%, with good linearity (R2 = 0.99). The method developed and validated was successfully applied in 54 gelatin samples, 57.4% of which showed clenbuterol. This UHPLC-MS/MS method combines high sensitivity with good selectivity and short chromatographic run time.