Aqueous Solubilities of Estrone, 17β-Estradiol, 17α-Ethynylestradiol, and Bisphenol A

The solubilities of three estrogenic hormonesestrone, 17β-estradiol, and 17α-ethynylestradioland the industrial pollutant bisphenol A were measured in water, dilute acid and alkali (pH 4 and 10, respectively), and aqueous KNO3 (0.01 mol·L-1 and 0.1 mol·L-1). The concentrations of saturated solutions, after equilibration at (25.0 ± 0.5) °C with excess solid for 4 days, were determined by HPLC. Six replicate results were obtained for each solute−solvent pair: the coefficient of variation was in most cases < 5 %. The solubilities in pure water with standard deviations were estrone (1.30 ± 0.08) mg·L-1, 17β-estradiol (1.51 ± 0.04) mg·L-1, 17α-ethynylestradiol (9.20 ± 0.09) mg·L-1, and bisphenol A (300 ± 5) mg·L-1. The solubility of each of the hormones was unchanged between pH 4 and pH 7 but was greater at pH 10. At pH 7, the hormones became progressively less soluble as the ionic strength increased from 0.0 to 0.1 mol·L-1. By contrast the solubility of bisphenol A was essentially the same under all of the experimental conditions tested.