Determination of naturally occurring estrogens and androgens in retail samples of milk and eggs
Résumé
The occurrence of the main steroid hormones (estrone, 17α-estradiol, 17β-estradiol, 17α-testosterone, 17β-testosterone, dehydroepiandrosterone, 4-androstenedione), especially through milk and eggs, was investigated. An analytical method based on GC-MS/MS was developed for steroid measurement at ultra-trace level in food products. Limits of detection for estrogens were found to be near 5 and 30 ng kg-1 in milk and egg sample respectively. For androgens, limits of detection were around 10 and 50 ng kg-1 in milk and egg samples respectively. This method was applied to milk samples and egg samples collected in a French supermarket. In milk, estrone was quantified at levels in-between 100 and 300 ng L-1, while 17β-estradiol levels were estimated near 20 ng L-1. 17α-testosterone was quantified from 50 ng L-1 in skim milk to 85 ng L-1 in whole milk. In egg samples, estrone and 17β-estradiol were quantified at 1.5 and 0.9 μg kg-1, respectively, while 17α-estradiol was found to be in lower concentrations (i.e. around 0.55 μg kg-1). Regarding androgens, 17α and 17β-testosterone were estimated at 1.9 and 1.3 μg kg-1, respectively. These results represent a first basis to estimate the food intake in steroid hormones. In next future, collection of additional data should permit the comparison between this exogenous dietary intake and the daily endogenous production of prepubertal children, as a basis of risk assessment regarding endocrine disruption linked to these molecules for this critical population.
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