Rapid multi-method for the determination of growth promoters in bovine milk by liquid chromatography-tandem mass spectrometry.

A rapid multi-method was developed for the determination of 21 growth promoters from different classes, including gestagens, corticosteroids, RALs, stilbenes, steroids in bovine milk by liquid chromatography-tandem mass spectrometry (LC-MS/MS). All compounds were eluted from the analytical column in less than 8.5min and were subsequently analyzed with atmospheric pressure chemical ionization (APCI) using both positive and negative mode. Sample preparation included extraction of the compounds with acetonitrile and purification with solid-phase extraction (SPE). The method was validated according to Commission Decision 2002/657/EC, at a validation level of 1ng/ml. The specificity, accuracy, precision, decision limit (CCα) and the detection capability (CCβ) were satisfactory evaluated. The recoveries ranged from 80.7% to 118.8% and reproducibility represented as coefficient of variance (CV) was from 1.8% to 13.0%. The CCα and CCβ values were in the ranges 0.06-0.10ng/ml and 0.11-0.17ng/ml, respectively. The developed method was applied in real samples proving its rapidness and sensitivity for the determination of the 21 growth promoters.