Simultaneous analysis of 17alpha-estradiol and 17beta-estradiol in bovine serum by liquid chromatography-tandem mass spectrometry.
A new LC-MS/MS method for the separation, identification and quantification of residues of 17alpha-estradiol (17alpha-E2) and 17beta-estradiol (17beta-E2) in bovine serum is reported. Deuterium-labelled 17beta-estradiol was used as internal standard. The method was in-house validated in accordance with European Union criteria and adopted in a proficiency study organised by the Community Reference Laboratory (CRL-RIVM, Bilthoven, The Netherlands). The analytes were extracted from serum using acetate buffer, purified by C18 solid-phase extraction (SPE) and chromatographed on a C18 LC column. They were then ionized in a heated nebulizer (HN) interface operating in negative ion mode, where only intact deprotonated molecules, [M-H](-), were generated at m/z 271 and 274 for 17alpha/17beta-E2 and 17beta-E2-d(3), respectively. The decision limits obtained (CCalpha, i.e., critical concentration alpha) were 0.06 ng/mL and 0.03 ng/mL, respectively for 17alpha-E2 and 17beta-E2. Detection capability (CCbeta, i.e., critical concentration beta) values were 0.08 ng/mL and 0.04 ng/mL, respectively, for 17alpha-E2 and 17beta-E2. Precision, accuracy and specificity were satisfactory, recovery ranged from 86.3% to 93.2% and the method resulted sensitive for the required purposes. This method is currently in use for Official Control purposes.
Ferretti
Giovanni
G
Istituto Superiore di Sanità, Department of Food Safety and Veterinary Public Health, Rome, Italy.
Ferranti
Carolina
C
Crovella
Teresa
T
Fiori
Maurizio
M
Civitareale
Cinzia
C
Marchiafava
Camilla
C
Quadri
Fernanda Delli
FD
Cammarata
Paolo
P
Palleschi
Luca
L
D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods*; D004958:Estradiol / Q000097:blood*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*
D004958:Estradiol