Development of a real-time immuno-PCR assay for the quantification of 17ß-estradiol in water.

A competitive real-time (RT) immuno-polymerase chain reaction (iPCR) (RT-iPCR) assay was developed for the sensitive quantification of 17ß-estradiol in water. Using a universal iPCR method and polyclonal antibodies, 17ß-estradiol was accurately quantified at concentrations ranging from 1 pg mL(-1) to 10 µg mL(-1). The RT-iPCR assay's limit of detection was 0.7 pg mL(-1). The RT-iPCR assay provided an 800-fold increase in sensitivity as well as an expanded working range compared with the corresponding enzyme-linked immunosorbent assay. Assay cross-reactivity to estrone and estriol, two structurally related estrogens, was below 8%. Water samples spiked with 17ß-estradiol were analyzed by RT-iPCR to determine the assay's potential as a rapid screen for the monitoring of manure-borne estrogens in the environment. The assay showed recoveries of 82, 102 and 103% for Milli-Q, tap, and irrigation water, respectively, without requiring sample extraction or concentration prior to analysis.