Investigation of internal standard substances for the determination of beta-estradiol in environmental samples

Abstract

Three deuterated beta-estradiol compounds (2, 4-d₂, 16, 16, 17-d₃, 2, 4, 16, 16-d₄) were investigated for use as internal standard substances in the determination of beta-estradiol. The mass spectrum of two of the deuterated compounds (2, 4-d₂, 2, 4, 16, 16-d₄) showed structural changes due to hydrolysis (1 M-HCl/methanol, 80°C, 20 min), which was required for the decomposition of conjugates in the sample pretreatment. On the other hand, the mass spectrum of the 16, 16, 17-deuterated compound was not changed. Therefore, we advise that beta-estradiol-16, 16, 17-d₃ should be used as the internal standard. In case where beta-estradiol-2, 4, 16, 16-d₄ must be used, it should be spiked after hydrolysis.