Analysis of Primary Aromatic Amines in Paper Products

A highly sensitive analytical method for 25 kinds of primary aromatic amines and azo-dyes in paper products was developed. Free amines and total amines of the samples were analyzed. The amount of each azo-dye was calculated from the amount of total amines by subtracting the amount of free amines. Amines and azo-dyes were migrated into water at 23 degrees C for 24 hours. Free amines were extracted into dichloromethane after alkalization with sodium hydroxide solution. Azo-dyes were reduced to amines with sodium dithionite, alkalized, and then extracted into dichloromethane as total amines. They were determined by GC/MS. The recoveries of 100 mu g/kg amines spiked into migration solution were in the range of 69-122%, except for 4,4'-oxydianiline and 4,4'-diaminodiphenylmethane which gave recovery rates of approximately 40%. The determination limits of amines were 4-20 mu g/kg in paper. Amines and azo-dyes were surveyed in 17 kinds of base paper and 16 kinds of paper products for food contact use. Aniline was detected at levels of 4-20 mu g/kg from most recycled papers, whereas the other amines were not detected in any sample.