Migration of ε-caprolactam from nylon cooking utensils: validation of a liquid chromatography-ultraviolet detection method

A large amount of modern cooking utensils are made of nylon. This is the generic name of polyamides that are polymers having characteristic amide linkages. Caprolactam is the monomer used in the synthesis of nylon 6. This work presents the validation of an LC-UV method for the determination of caprolactam in the aqueous food simulant 3% acetic acid (w/v) employing capryllactam as internal standard. LC-MS/MS was the confirmation technique. The obtained detection and quantification limits were satisfactory regarding caprolactam specific migration limit; these were 0.6 and 2 mg kg(-1), respectively. The working range was 2-30 mg kg(-1) and the correlation coefficients (r) were in all cases at least 0.999. The intra-day repeatability was between 2.5 and 4.8% depending on the validation level. The global mean recovery was 100.6% with a RSD (%) of 5.0%. Different nylon cooking utensils were analyzed for the migration of caprolactam in the food simulant acetic acid 3% p/v. Conditions used were repeated exposure to the simulant for 2 h at 100 A degrees C, and the results obtained after the third exposure were in compliance regarding Directive 2002/72/EC. With the aim of identifying the polymer used in these utensils, IR spectra were also obtained for all samples.