Gas chromatographic method for ethylene dibromide in grains and grain-based products: collaborative study

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Residue Analysis

Background:

• Ethylene dibromide (EDB) is a fumigant used on grains, posing potential residue concerns in food products.
• Accurate detection methods are crucial for monitoring EDB levels in the food supply.
• Previous analytical methods required validation for diverse food matrices.

Purpose of the Study:

• To collaboratively analyze and validate a method for determining ethylene dibromide (EDB) residues.
• To assess the method's performance across different food types, including whole grain, intermediate, and ready-to-eat products.
• To establish official first action status for the validated EDB residue analysis method.

Main Methods:

• Nine laboratories participated in a collaborative study analyzing fortified and incurred EDB in wheat, rice, flour, corn bread mix, baby cereal, and bread.
• Extraction involved soaking in acetone-water for whole grains and intermediates, and a modified hexane co-distillation for baby cereal and bread.
• Ethylene dibromide (EDB) was quantified using electron capture gas chromatography with an SP-1000 column.

Main Results:

• Overall mean recoveries for EDB ranged from 85.2% to 105.0% across different food samples.
• Interlaboratory relative standard deviations varied from 5.7% (wheat) to 20.2% (baby cereal) for fortified samples.
• Mean levels of incurred EDB in wheat, rice, and flour were 926.7, 982.0, and 49.9 ppb, respectively, with relative standard deviations between 7.7% and 13.1%.

Conclusions:

• The analytical method demonstrated acceptable performance for EDB residue determination in a variety of food products.
• The collaborative study successfully validated the method, leading to its adoption as official first action.
• This validated method provides a reliable tool for monitoring EDB contamination in the food supply.