pKa values of estrone, 17β-estradiol and 2-methoxyestrone

Sorption of four estrogens by surface soils from 41 cultivated fields in Alberta, Canada

“…The pK a values of 17β-estradiol, estrone and estriol range from 10.3 to 10.8 (Hurwitz and Liu, 1977;Lewis and Archer 1979) and the pH of the Alberta soils ranges from 4.2 to 7.5. As such, most of the estrogen molecules were non-ionized with SOC being the most important soil characteristic explaining the variation in K d -17β-estradiol, K d -estriol, K d -estrone and K d -equol values across the 121 soil samples.…”

On-line coupling of solid-phase extraction to high-performance liquid chromatography for determination of estrogens in environment

“…pKa values of estrogens are around 9-10 [67], and results show that the pH of samples slightly affect the extraction efficiency for SPE cartridges when the pH is lower than 9. The effect of the pH of the sample solution was evaluated using 5.0 g L −1 working standard solutions in a pH range of 3.0-11.0.…”

Sampling and Conservation

“…Only one study is known to the author in which the pH value was varied: Zhang et al (2008) determined uptake rates for estrone, 17b-estradiol, 17a-ethynylestradiol, and bisphenol A, which have pK a values of 10.8, 10.5, 10.7, and approximately 10.0, respectively (Lewis and Archer, 1979;Staples et al, 1998). POCs often possess many functional groups and can be present in the environment in ionized or neutral form, based on the pH.…”