Adsorption and Desorption of Selected Estrogens on Materials Commonly Used in Water Sampling and Sample Handling

The adsorption and desorption of four estrogens - estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2) - on six different plastic and rubber materials commonly used for laboratory equipment and sample handling, was investigated at environmentally relevant concentrations (100 – 500 ng/L) in deionized and tap water matrices. After 30 min soaking, PVC, PTFE, Kynar® and EPDM materials adsorbed only negligible amounts of estrogens (less than 20%). Significant amounts of E1, E2 and EE2 were adsorbed onto Tygon S3™ material, and nearly half of the adsorbed estrogens were subsequently desorbed within 90 min. Styrene butadiene rubber (SBR) adsorbed E1 considerably, but its desorption was negligible. Detailed testing of ethylene propylene diene monomer (EPDM) at elevated concentrations and soaking time showed a significant sorption of EE2 (up to 50% of initial concentration) after 12 hours of soaking in both water matrices, the adsorption of other estrogens reached less than 17%. The overall concentration of estrogens desorbed during 90 min reached up to 10% for E1, E2 and EE2; the desorption of E3 was negligible. The results show that careful selection of materials should be considered for sample handling, especially when low environmentally relevant concentrations are analyzed.