Determination of 17beta-estradiol in bovine plasma: development of a highly sensitive technique by ion trap gas chromatography-tandem mass spectrometry using negative chemical ionization.
A novel approach to the determination of 17beta-estradiol in bovine plasma is presented. The observed enhanced sensitivity is gained by the application of tandem mass spectrometry (MS) fragmentation to a stable, well characterized negative ion produced by chemical ionization (methane as reagent gas). A specific derivatizing reactant is employed (pentafluorobenzyl bromide), combined with bis-trimethylsilyltrifluoroacetamide, to favor the formation of a diagnostic precursor negative ion. Plasma samples are purified through a C18 solid phase extraction column and derivatized before gas chromatography-MS analysis. The accuracy and the precision of the method, tested over a set of spiked samples, were satisfactory. The limit of detection was found to be 5 pg ml(-1) and the limit of quantification was fixed at 20 pg ml(-1). The fragmentation pattern is fully explained and the method is applicable for the official analysis of bovine plasma for the detection of 17beta-estradiol according to the European criteria 256/93 and to the draft SANCO/1805/2000 rev. 3. The quantification of incurred positive samples was performed according to the proposed procedure and compared with the results obtained by standardized radio immuno assay; the estimated concentrations were significantly similar.
Biancotto
Giancarlo
G
Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (PD), Italy. biancottog@izsvenezie.it
Angeletti
Roberto
R
Traldi
Pietro
P
Silvestri
Massimiliano
M
Saccon
Mauro
M
Guidugli
Federico
F
D000818:Animals; D002417:Cattle; D004958:Estradiol / Q000097:blood* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007477:Ions; D015394:Molecular Structure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D007477:Ions; D004958:Estradiol