MIGRATION STUDIES FROM PAPER AND BOARD FOOD-PACKAGING MATERIALS .2. SURVEY FOR RESIDUES OF DIALKYLAMINO BENZOPHENONE UV-CURE INK PHOTOINITIATORS

A survey of retail samples was conducted in two phases with 50 general paper and boardfood contact materials and articles analysed in 1992, and 121 samples, specifically of printed cartonboard, analysed in 1995 . Packaging samples were extracted with ethanol containing 0.4% trieth ylamine. The extracts were analysed using high performance liquid chro matography (HPLC) and the presence of 4,4'-bis(dimethylamino)benzophen one (Michler's ketone, MK) and 4,4'-bis(diethylamino)-benzophenone (DE AB) confirmed using gas chromatography coupled to mars spectroscopy (G C-MS). The limits of detection for MK and DEAB in packaging were 0.05 mg/kg and 0.1 - 0.2 mg/kg respectively. In the first phase, MK was det ected in 24% of the 50 samples at concentrations of 0.06-3.9 mg/kg pap er. DEAB was detected in 12% of samples (0.1 - 0.2 mg/kg). In the seco nd phase, 26% of the 121 cartonboard samples contained detectable MK ( 0.1 - 1.6 mg/kg) and 4% contained DEAB (0.2-0.7 mg/kg). Residues of th e monoamine 4-(dimethylamino)benzophenone (DMAB) were found in 10% of the 1992 samples (0.1-0.6 mg/kg). DMAB was not surveyed in 1995. These levels are too low to indicate the use of these cure agents for print ing the packages. Rather, the most likely origin is from the use of re cycled fibres. For three samples where the highest concentration of MK was detected, the food was analysed by GC-MS after extraction and cle an-up. There was no measurable migration of MK at a detection limit of 2 mu g/kg food. It is concluded, therefore, that the concentrations o f MK present in the packaging samples analysed are unlikely to pose a risk to human health.