Sample clean-up by sol-gel immunoaffinity chromatography for the determination of bisphenol A in food and urine

Bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA) is an industrial chemical mainly used as a monomer in the synthesis of polycarbonates and epoxy resins. BPA has been shown to elicit estrogenic effects via binding to the nuclear estrogen receptors alpha and beta. Food is considered as the major source of BPA exposure for the general human population. When incorporated into the body, BPA is metabolised in the liver, mainly to BPA glucuronide, and excreted via the urine. The present paper presents analytical methods for the determination of BPA concentrations in foodstuffs and the determination of free and total (free plus conjugated) BPA in urine samples. The paper provides protocols for the preparation and operation of sol-gel immunoaffinity columns and their application to remove interfering matrix compounds and to enrich BPA. In addition, the paper points out major sources of systematic errors in BPA analysis and describes how they can be avoided.