Gas chromatography-mass spectrometry/mass spectrometry analysis to determine natural and post-administration levels of oestrogens in bovine serum and urine.
A novel analytical approach has been developed and shown to be capable of detecting the isomers of oestradiol in the low ppt (pg mL(-1)) range in bovine serum and urine. Following extractive derivatisation the analytes were detected as their 3-pentafluorobenzoyl 17-trimethylsilyl ether derivatives by gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS), using electron capture negative ion chemical ionisation. The isomers of oestradiol were quantified in both blank and post-administration urine and serum samples, with a view to setting action/threshold levels for these compounds, to allow discrimination between normal samples and samples from animals treated with growth promoting ear implants. A non-parametric statistical assessment of the data resulted in proposed action levels (with a false positive probability of 1 in 1000) of 1.6 and 2.7 ng mL(-1) for 17alpha-oestradiol, in male and female urine, respectively, and 40 and 44 pg mL(-1) for 17beta-oestradiol, in male and female urine, respectively. An action level of 20 pg mL(-1) was proposed for 17alpha- and 17beta-oestradiol in male serum. In female serum the proposed action levels were 40 and 20 pg mL(-1) for 17alpha- and 17beta-oestradiol, respectively.
Biddle
S
S
HFL, Newmarket Road, Fordham, Cambridgeshire, UK. sbiddle@hfl.co.uk
Teale
P
P
Robinson
A
A
Bowman
J
J
Houghton
E
E
D045930:Anabolic Agents / Q000032:analysis; D000818:Animals; D002138:Calibration; D002417:Cattle; D004967:Estrogens / Q000008:administration & dosage / Q000097:blood* / Q000652:urine*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D008297:Male; D008956:Models, Chemical; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors
D045930:Anabolic Agents; D004967:Estrogens