Fast analysis of relative levels of dehydroabietic acid in papermaking process waters by on-line sample enrichment followed by atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS)

Resin acids are considered to be significant contributors to the toxicity of pulp mill effluents. Traditionally, the analysis of these acids is performed by liquid–liquid extraction followed by gas chromatography. This paper describes a method suitable for monitoring the relative concentration levels of the main resin acid component, dehydroabietic acid (DHAA), in process waters by atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS). This method was further improved, first by testing different precolumns for on-line sample clean-up and then by developing the APCI-MS analysis of the analytes trapped in the precolumn (i.e., solid-phase extraction column). The external standard, internal standard, and response factor methods were compared. The curve profiles of the results obtained with the above determinations were very similar to each other. This finding suggested that the rapid APCI-MS method, using a selected ion monitoring (SIM) technique, is a potential tool for monitoring relative concentration levels of DHAA. The technique is also recommended for rapid and simple monitoring of DHAA as well as of other resin acids, and their derivatives, such as their chlorinated analogues, in various aquatic environmental samples.