Persistent organic pollutants (POPs) in human follicular fluid and in vitro fertilization outcomes, a pilot study.

Persistent organic pollutants (POPs) are ubiquitously distributed among the U.S. population and adversely impact human reproduction. These compounds have been detected in human ovarian follicular fluid (FF), where they directly contact a developing oocyte. As a pilot investigation, we measured 43 polychlorinated biphenyl (PCB) congeners, p,p'-dichlorodiphenyltrichloroethane (DDT), and its persistent metabolite p,p'-dichlorodiphenyldichloroethylene (DDE) in residual FF collected from 32 women undergoing in vitro fertilization (IVF). We identified significant inverse associations between higher levels of PCB congeners and indicators of ovarian reserve (e.g., antral follicle count), follicular response to administered gonadotropins (e.g., peak estradiol, number of oocytes retrieved, endometrial thickness), intermediate IVF endpoints (e.g., oocyte fertilization and embryo quality), and clinical IVF outcomes (e.g., embryo implantation and live birth), after adjusting for body mass index, cigarette smoking, race, and age. Our results suggest that ongoing exposure to POPs impacts IVF and merit confirmation in a larger and more definitive future study.

Use of methanol for the efficient extraction and analysis of melamine and cyanuric acid residues in dairy products and pet foods.

The recent worldwide shortage of acetonitrile has prompted the development of a new method using methanol as an alternative organic solvent in the extraction and liquid chromatographic analysis of melamine and cyanuric acid that may be present as contaminants in dairy products and pet foods. A simple extraction of melamine and cyanuric acid residues in fortified samples was successfully achieved, using a methanol-water mixture and analysis by isotopic dilution high-performance liquid chromatography-triple-quadrupole mass spectrometry (HPLC-MS/MS). A two-step centrifugation procedure was employed to remove matrix components from extracts. The separation of melamine and cyanuric acid was carried out on a Dionex Acclaim Trinity P1 column, with a methanol and ammonium acetate buffer used as the mobile phase. Excellent linearity was achieved for both the melamine and cyanuric acid calibrations. A variety of dairy products and pet foods were fortified with melamine and cyanuric acid at three levels, 1, 2.5, and 10 microg/g, producing recovery yields of 101-119% for melamine and 84-123% for cyanuric acid. The lower limit of quantification (LLOQ) of melamine was 0.03 microg/g for liquid milk and 0.05 microg/g for dry infant milk formula. The quantitative results were comparable with those derived from previous methods that have been proposed by the U.S. Food and Drug Administration for the screening of melamine and its analogues in foods.