Detection of rosin (colophony) components in technical products using an HPLC technique

A method for detection of rosin (colophony) in technical products has been developed. The technique, using HPLC, is based on the analysis of abietic acid and dehydroabietic acid, major components of rosin. In the procedure described in this paper, the limit of detection was 0.001% for abietic acid and 0.015% for dehydroabietic acid. An average recovery of 88.9% for abietic acid and 88.2% for dehydroabietic acid was obtained. The lowest detectable amount of abietic acid (0.001%) corresponds to a content of 0.003% unmodified rosin in the product, assuming that the resin acid content in rosin is 90%, of which 30-50% is abietic acid. This is an acceptable limit compared to the reactivity in patients with known allergy to rosin. Technical products for analysis were supplied by different Swedish manufacturers, who also gave the approximate content of rosin in the various products. The content of rosin determined in the products was in accordance with the contents given by the manufacturers.