Volatile N-nitrosamines in baby bottle rubber nipples and pacifiers. Analysis, occurrence and migration.

A simple direct extraction method has been developed for rapid determination of volatile N-nitrosamines in rubber nipples and pacifiers. It consists of overnight extraction of the sample with dichloromethane in the presence of ascorbyl palmitate for N-nitrosation inhibition, filtration of the extract and rinsing of the samples with dichloromethane, concentration of the extract using a Kuderna-Danish concentrator, and final analysis by gas-liquid chromatography-Thermal Energy Analyser. The method gave excellent (80-100%) recoveries of various volatile N-nitrosamines that had been added to cut nipples or pacifiers at 20-80 micrograms/kg levels, and gave comparable or lower values than those obtained with another published method. The method is recommended for rapid screening purposes. A survey of 30 samples of various nipples and pacifiers indicated the presence of the following N-nitrosamines: N-nitrosodimethylamine (up to 70 micrograms/kg), N-nitrosodiethylamine (up to 88 micrograms/kg), N-nitrosodi-n-butylamine (up to 2796 micrograms/kg), N-nitrosopiperidine (up to 180 micrograms/kg), and N-nitrosomorpholine (up to 86 micrograms/kg). A more recent study, however, indicated a general decline in the levels of various volatile N-nitrosamines in these products. These N-nitrosamines were shown to migrate easily from the rubber products to liquid infant formula, orange juice and simulated human saliva.