Detection of corticosteroids in injection sites and cocktails by MSn

In the European Union, the use of growth promoting substances such as thyreostats, anabolics (products with estrogenic, androgenic or gestagenic action) and beta-agonists in animal fattening is forbidden. Corticosteroids, such as dexamethasone, although considered catabolic substances, have been administered to food producing animals in order to achieve mass gains. For the analysis of injection sites and of suspect cocktails (found at the farm), a number of HPTLC and HPLC methods are used. However, in injection sites and also in cocktails found at the farm, sometimes many unknown substances are found. In this investigation, a multiple mass spectrometric (MSn) method was developed. The method is based on rapid extraction of the matrix with methanol and direct infusion of the extract into the interface of the mass spectrometer. Tables that summarise the masses of corticosteroids and their possible esters are presented.