Determination of Estrogens in Foods by Derived Cucurbituril-Coated Stir Bar Sorptive Extraction Combined with High-Performance Liquid Chromatography

A method of stir bar sorptive extraction (SBSE) based on monohydroxyl cucurbit7 uril (Q7-OH)-liquid desorption (LD)-high performance liquid chromatography (HPLC)-ultraviolet detection was developed for measurement of three residual estrogens (bisphenol A, estradiol and diethylstillbestrol) from animal-derived foods (pork and chicken samples). The hydroxyl polydimethylsiloxane (PDMS-OH)/Q7-OH-coated stir bar was conducted by the sol-gel technique with the synthesized Q7-OH as a selective stationary phase. The innovative SBSE exhibited a rough and porous surface structure, a good preparation reproducibility (RSD <= 8.4%) and a long lifespan. Extraction mechanism indicated that the increase of extraction efficiency was attributed to the excellent molecular recognition of Q7 towards analytes. Under the optimal experimental conditions, the limits of detection of the developed PDMS/Q7-OH SBSE-LD-HPLC-UV method were 0.05-0.56 mu g/L for the target estrogens with enrichment factors of 19-25 folds, the dynamic linear range was 0.2-5000 mu g/L, and the RSDs were in the range of 3.9% -7.5% (n = 5, C = 100 mu g/L). The mean recoveries (n=3) at three different concentration levels were 72.7%-109.2%. The developed method was simple, sensitive, and selective, and was successfully applied to the analysis of estrogens in animal-derived foods (pork and chicken samples).