Multiresidue determination of estrogens in different dairy products by ultra-high-performance liquid chromatography triple quadrupole mass spectrometry.

In this work, a simple and fast methodology has been validated and applied for the analysis of a group of 22 estrogenic compounds including eight phytoestrogens (i.e. daidzein, enterodiol, glycitein, enterolactone, genistein, formononetin, prunetin, biochanin A), six mycotoxins (β-zearalanol, β-zearalenol, α-zearalanol, α-zearalenol, zearalanone, zearalenone) as well as four synthetic (i.e. ethynylestradiol, diethylstilbestrol, dienestrol, hexestrol) and four natural estrogens (i.e. estriol, 17β-estradiol, 17α-estradiol, estrone) in different dairy products. Extraction was carried out using the QuEChERS method while separation, determination and quantification of the target analytes were achieved by ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry with an electrospray ionization interface. The methodology was validated for four dairy product samples with relevant interest for the population including skimmed and whole cheese and goat and cow kefir, using 17β-estradiol-2,4,16,16,17-d as internal standard for natural and synthetic estrogens and β-zeralanol-10,10,11,12,12-d as internal standard for mycotoxins and phytoestrogens. Recovery ranged from 70 to 119% for the four types of matrices with RSD values lower than 14% and the limits of quantification of the method achieved were in the range 0.025-2.50μg/kg for all samples. Finally, the analysis of commercially available products was carried out finding the presence of daidzein, glycitein enterolactone and genistein in some of the studied samples.