Development of fast analysis methods for extractives in papermaking process waters

Abstract

A fast analysis method with an online sample enrichment technique for the analysis of resin and fatty acids present in papermaking process waters was developed. This method was based on atmospheric pressure chemical ionization (APCI) and mass spectrometry (MS) for the detection of [M-H]- ions of compounds of interest. The method was applied to the control of the most prevalent resin (dehydroabietic and abietic) and fatty (palmitic, stearic, oleic, and linolenic) acid levels in papermaking process waters. Continuous data on these acids are of practical importance when predicting possible deposit-derived problems in the paper machine. The first part of the study was focused on the development of an online sample enrichment system for the analysis equipment used. The method was partially validated and tested for the selected resin and fatty acids in aqueous media and papermaking process waters. The online sample enrichment step was connected to the analytical system through a standard high-performance liquid chromatography (HPLC) precolumn and time-controlled column switching valves. In the second part, the feasibility of the method developed was tested by means of three different applications: laboratory-scale online sample enrichment studies, enrichment of resin and fatty acids when increasing water reuse, and the development of a faster offline laboratory method with HPLC column separation. The column separation was validated by means of selectivity, repeatability, precision, and limits of detection (LOD). These validation results clearly indicated that the HPLC-APCI-MS method with column separation was applicable for this purpose. The analysis system developed provides a potential tool for monitoring selected resin and fatty acids for many applications of practical importance. It was noticed that measuring only the resin acid concentration level, for example, may offer a possible indirect control method for papermaking. The results also indicated that the fast offline HPLC-APCI-MS technique with column separation of the compounds of interest is a useful alternative to other traditional analysis methods such as gas chromatography (GC). The main benefits of this new method are simplicity of use, absence of the need for multistage sample pretreatment, and rapidity of measurement.