Volume 06, Number 1
Jun 1993

A Spot Test for Lignin that's Too Hazardous for General Use

A technical note in the last Abbey Newsletter reported comparative tests for two spot tests for lignin in paper, carried out in the lab of the National Library of Australia. They used phloroglucinol, which is widely used by waste paper dealers and librarians, and aniline sulfate, an indicator which is about as accurate as phloroglucinol, but cheaper. At press time, the hazards connected with using this aniline compound are still being ascertained, and a complete report will have to wait until next issue.

In the meantime, the best thing seems to be for all who are not trained professionals to stay away from it. The American Conference of Governmental Industrial Hygienists (ACGIH) currently assigns a TLV (threshold limit value, the maximum safe exposure in an industrial setting) to aniline and its homologues of 2 parts per million (ppm) and notes that skin absorption also can be a significant source of exposure. To put the TLV in perspective, carbon tetrachloride has a higher TLV (5 ppm), indicating that even carbon tetrachloride is less toxic than aniline.

Thanks to Monona Rossol, who sent in this and other information in a timely manner, under a press deadline.