Selective determination of trace 17β-estradiol in dairy and meat samples by molecularly imprinted solid-phase extraction and HPLC.

Molecularly imprinted solid-phase extraction (MISPE) combined with HPLC were used to detect trace 17β-estradiol (E2) in different dairy and meat samples. E2 imprinted mono-dispersed microspheres prepared by modified precipitation polymerisation method were used as MISPE sorbents. Under optimum MISPE and HPLC conditions, trace (0.116-0.461nmolkg(-1)) E2 in different dairy and meat samples can be detected accurately using UV detector when large amount of sample (500g) was analysed. Recoveries of E2 from spiked (0.1-5nmolkg(-1)) milk, yogurt, beef, pork and chicken were higher than 74.18%, 71.92%, 67.21%, 64.20% and 65.93%, respectively with RSDs less than 8.38%. MISPE can enrich E2 selectively, which is helpful to have better HPLC separation and higher recoveries than C18 SPE. MISPE combined with HPLC-UV are reliable methods to determine trace E2 in dairy and meat samples with high accuracy and repeatability.