From the 2005 FDA Science Forum
The Use of Electrodialysis to Prepare Aqueous Bread Extracts for Bromate Determination by Chemiluminescence
K. Himata1 , C. R. Warner2 , D. Currie3 , Q. Graves4 , G. W. Diachenko2 , 1Yamazaki Baking Co., 2OFAS/DCRER, 3Univ. of Maryland/Physics, 4OO/OSAS/DM
Background: Potassium bromate (PB) has been used by the baking industry as
a dough conditioner since 1914 when a patent was issued by the United States
Patent Office. Long-term toxicological studies based on drinking water for rats have established PB as a renal carcinogen. Quantitative risk analysis indicates that residues in the finished bread above 20 ppb in baked goods would lead to a potentially significant level of risk. Electrophoresis and chemiluminescence were studied as fundamental principles for a quick test for bromate at 20 ppb in bread.
Methods: A cleanup procedure based upon electrodialysis with three chambers separated by semi-permeable membranes is used to prepare the bread extracts for chemiluminescence. The relative merits of reverse osmosis (RO), ultrafiltration and nanofiltration membranes were evaluated. After electrophoretic separation with a RO membrane the bromate concentration in the collection chamber was typically 2 to 3 times greater than the concentration in the bread extract.
The chemiluminescent reaction of bromate with sulfite with hydrocortisone as the enhancer was selected for detection of bromate. The emission, with a wavelength maximum at 575 nm, was found to glow rather than flash after the reagents were mixed; therefore, it was possible to optimize the light collection period.
The method was validated with a variety of commercial bread products. White bread, hot dog buns, hamburger rolls and a multigrain bread from seven different manufacturers were studied.
Conclusions: The combination of electrodialysis and chemiluminescence provides a quick test for bromate in baked goods at levels of 20 ppb and above.