Determination of 2,4,6-tribromoaniline in the color additives D&C Red Nos. 21 and 22 (Eosin Y) using solid-phase microextraction and gas chromatography-mass spectrometry.

The present work demonstrates the presence of an impurity, 2,4,6-tribromoaniline (TBA), in the color additives D&C Red Nos. 21 and 21 lake (21L) and describes the determination of TBA in certified lots of D&C Red Nos. 21, 21L and 22 (Eosin Y). A method was developed using solid-phase microextraction with [13C6]TBA as an internal standard followed by gas chromatography-mass spectrometry analysis. Test portions from 23 lots of US-certified color additives D&C Red Nos. 21, 21L and 22 were analyzed for TBA using the new method. These lots represent domestic (four) and foreign (four) manufacturers that requested certification for the color additives during the past 2 years. Of the test portions analyzed, 12 (52.2%) contained TBA in amounts ranging from 19.9 to 638.9 ppm with an average value of approximately 278.7 ppm. The remaining 11 (47.2%) test portions contained no detectable TBA or less than 0.01 ppm, which is the limit of quantification of the present method. The wide range of TBA levels found in lots submitted for certification suggest that the contamination with TBA may be avoided or significantly decreased through appropriate changes in the color-manufacturing process.