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 (CC alpha) and detection capability (CC beta). 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 (1)H-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.

Residue analysis of glucocorticoids in bovine milk by liquid chromatography-tandem mass spectrometry / Caretti, Fulvia; Gentili, Alessandra; Ambrosi, Annalisa; MAINERO ROCCA, Lucia; Delfini, Maurizio; DI COCCO, Maria Enrica; D'Ascenzo, Giuseppe. - In: ANALYTICAL AND BIOANALYTICAL CHEMISTRY. - ISSN 1618-2642. - STAMPA. - 397:6(2010), pp. 2477-2490. (Intervento presentato al convegno 6th International Conference on Instrumental Methods of Analysis tenutosi a Athens, GREECE nel OCT 04-08, 2009) [10.1007/s00216-010-3774-9].

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

CARETTI, Fulvia;GENTILI, Alessandra;AMBROSI, Annalisa;MAINERO ROCCA, Lucia;DELFINI, Maurizio;DI COCCO, Maria Enrica;D'ASCENZO, Giuseppe
2010

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 (CC alpha) and detection capability (CC beta). 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 (1)H-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.
2010
bovine milk; electrospray; glucocorticoids; hplc-ms/ms; matrix effect; triamcinolone
01 Pubblicazione su rivista::01a Articolo in rivista
Residue analysis of glucocorticoids in bovine milk by liquid chromatography-tandem mass spectrometry / Caretti, Fulvia; Gentili, Alessandra; Ambrosi, Annalisa; MAINERO ROCCA, Lucia; Delfini, Maurizio; DI COCCO, Maria Enrica; D'Ascenzo, Giuseppe. - In: ANALYTICAL AND BIOANALYTICAL CHEMISTRY. - ISSN 1618-2642. - STAMPA. - 397:6(2010), pp. 2477-2490. (Intervento presentato al convegno 6th International Conference on Instrumental Methods of Analysis tenutosi a Athens, GREECE nel OCT 04-08, 2009) [10.1007/s00216-010-3774-9].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/230486
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