HPLC Determination of 6 Aromatic Amines Migrated from Food Contacting Materials with Extraction by Ionic Liquid

A method of HPLC for the determination of 6 aromatic amines, i.e., 4,4′-methyenedianiline, 2,4-dimethylaniline, 4-chloro-o-toluidine, 4-aminobiphenyl, 3,3′-dichlorobenzidine and 4-aminoazobenzene migrated from food contacting materials was proposed. The sample was soaked in 25.0 mL of water or acetic acid solution (3+97). The soaking solution was mixed with 0.652 3 g of ionic liquid ［C6mim］［PF6］ which is used as extractant. Acidity of the mixture was adjusted to pH 8 with PBS or aq. ammonia. After addition of 1.25 g of NaCl, the mixture was extracted by vortical shaking for 5 min, and then centrifuged for 5 min, the lower ionic liquid phase was taken and used for HPLC analysis. Diamonsil C18 column was used as the stationary phase and mixtures of water and acetonitrile used as mobile phase. Detection was made at the wave length of 235 nm. Linearity ranges of 6 the aromatic amines were between 0.02-2.0 mg·L-1. The limits of detection (3S/N) found were from 4.0 to 10.0 μg·L-1. The proposed method was applied to the analysis of a sample of Nylon spoon, and recovery was tested by standard addition method, giving values of recovery and RSD′s (n=7) in the ranges of 91.6%-106% and 1.4%-8.8% respectively.