Determination of oestrone, 17alpha- and 17beta-oestradiol in bovine aqueous humor using gas chromatography-negative ion chemical ionization mass spectrometry.

Perfluorotolyl (PFT)-ether and perfluorotoly-trimethylsilyl (PFT-TMS) ether derivatives of oestrone, 17alpha- and 17beta-oestradiol were prepared under phase transfer conditions. The former derivatives under negative ion chemical ionization conditions gave significant ions in the mass spectrometer but 17alpha- and 17alpha-oestradiol gave poor resolution. However, the PFT-TMS derivatives of 17alpha- and 17beta-oestradiol showed good resolution. These derivatives were used for the analysis of oestrogens in bovine aqueous humour, vitreous humour and retina. The mean (+/-SEM) concentrations of oestrone in bovine aqueous humour (n=18), vitreous humour (n=18) and bovine retina (n=4) were 0.47+/-0.11, 0.46+/-0.14 and 1.10+/-0.24 ng.ml(-1), respectively. 17alpha-Oestradiol was detected in 16 out of 18 samples of bovine aqueous humour and vitreous humour and the mean (+/-SEM) concentrations were 0.30+/-0.10 and 0.08+/-0.02 ng.ml(-1), respectively. The mean (+/-SEM) concentration of 17beta-oestradiol in aqueous humour (n=7) and vitreous homour (n=11) 0.83+/-0.26 ng ml(-1) and 0.39+/-0.09 ng ml(-1), respectively. In retina the concentrations of both steroids were below the detection limit.