Determination of acrylonitrile in foods by headspace gas-liquid chromatography with nitrogen-phosphorus detection

A general procedure is described for the determination of acrylonitrile (AN) in foods such as margarine, honey butter, cold-pack cheese, and peanut butter, which are likely to be packaged in AN-based plastic. The entire sample is blended with water and salt at less than 5 degrees C, aliquots are sealed in crimp-top vials, and the vials are equilibrated in a boiling water bath. The headspace is sampled by using a heated syringe, and AN is determined by gas chromatography with a nitrogen-phosphorus selective detector. The inclusion of propionitrile as an internal standard allows quantitation of AN with detection at 4,4, and 10 ppb for margarine, honey butter, and cold-pack cheese, respectively. A peak corresponding to about 5 ppb apparent AN in all non-AN-packaged peanut butter samples examined limits detection in peanut butter to about 15 ppb. The coefficients of variation at 20 ppb for margarine, honey butter, cold-pack cheese, and peanut butter were 7.5, 8.3, 7.3, and 10.2%, respectively.