TITLE

Residue analysis of glucocorticoids in bovine milk by liquid chromatography–tandem mass spectrometry

AUTHOR(S)
Caretti, Fulvia; Gentili, Alessandra; Ambrosi, Annalisa; Rocca, Lucia Mainero; Delfini, Maurizio; Cocco, Maria Enrica Di; D'Ascenzo, Giuseppe
PUB. DATE
July 2010
SOURCE
Analytical & Bioanalytical Chemistry;Jul2010, Vol. 397 Issue 6, p2477
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 13 steroidal anti-inflammatory drugs in bovine milk is presented. Due to their weakly acid nature, analytes were separated by ion suppression reversed phase chromatography and detected in positive-ion mode by a high flow electrospray source. Dexamethasone-d4 was used as internal standard. The sample preparation was simple and reliable; it included acidic deproteinization of milk followed by sample enrichment and clean-up, utilizing a C18 solid phase extraction cartridge. Recoveries exceeded 70% with an intra-day precision not larger than 12%. The efficiency of the sample clean-up and internal standardization rendered negligible the matrix effect, estimated by comparing standard and matrix-matched calibration curves. A small-scale reconnaissance was carried out on several raw and whole fresh milk samples. A large number of analyzed samples showed a chromatographic peak, in the retention time window of cortisol, at levels included between its decision limit (CCα) and detection capability (CCβ). As a result of a heat-induced transformation, an isomeric product of triamcinolone was observed during the extract evaporation. Since this rearrangement might occur during the milk pasteurization process, LC-MS/MS and 1H-NMR investigations were performed out to conclusively differentiate the two isomers. One- and two-dimensional proton NMR spectra were able to identify the transformation product as 9a-fluoro-11b,16a-trihydroxy-17b-hydroxymethyl- D-homoandrosta-1,4-diene-3,17a-dione.
ACCESSION #
51880403

 

Related Articles

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics