Advisory Committee on Health Effects of Endocrine Disruptors
The Supplement II to the Intermediary Report
1.2.3.2

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[Notes]
Bisphenol A (BPA), first synthesized in 1891, is widely used as a starting material for polycarbonate and epoxy resins, and as a stabilizer for PVC. About 130 thousand tons of BPA was produced in Japan in 2001. The substance, a condensation product from two phenol molecules and an acetone molecule, is white powder readily soluble in acetone or methanol but hardly soluble in water.
As for metabolism and kinetics, BPA in humans is rapidly absorbed in the digestive tract, metabolized to glucuronic acid conjugate in the liver, and eliminated to urine. Most of BPA (80-97%) taken up is removed within 24 hours regardless of exposure to low concentration (50μg) or high concentration (1 mg).
In contrast, in an experiment with rats, 80% of BPA orally administered (800 mg/kg) was eliminated into urine and, principally, into feces within two days. Elimination was complete after eight days.
Thus the metabolism of orally administered BPA is highly dependent on the species involved: principally to feces in rats and to urine in humans and monkeys.

1. LC/MS is simple in that no derivatization is needed, but susceptible to influences of foreign substances.
2. This procedure is principally for analysis of urine. Pentafluorobenzylation combined with NCI-GC/MS may also be used.
3. BPA-d16 may also be used.
4. E.g. Isolute Multimode manufactured by International Sorbent Technology, Ltd.
5. E.g. Supelco Supelclean ENVI-18.
6. E.g. Supelco Supelclean ENVI Florisil.
7. BSTFA = N,O-Bis(trimethylsilyl)trifluoroacetamide, supplied by e.g. GL Sciences, Inc.
8. Since BPA is present in plastic and rubber used in labware as well as in purified water, the blank value must be kept as low as possible by the following in order to achieve a sufficiently high sensitivity.
• Use Milli-Q water which contains a very low level of BPA.
• Clean glassware with acetone before use.
• Condition the cartridges with an appropriate amount of a solvent.
• Use glass microsyringes (instead of plastic tips) for transferring small amounts of reagents.
• Clean the inside of the evaporator thoroughly by boiling acetone.
9. E.g, Agilent Technologies' Zombax XDB.
10. Use of 0.01% acetic acid-acetonitrile (55:45) as the mobile phase is not impossible, but susceptible to interference when analyzing urine.
11. E.g. J & W Scientific's DB-5MS.

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