Determination of polyacrylamide based flocculants in sewage sludge by off-line thermochemolysis-GC–MS analysis

Abstract

Abstract This study aimed to develop an offline thermochemolysis method for the determination of cationic polyacrylamide (cPAA) flocculants in environmental samples, using trimethylanilline hydroxide as a thermochemolytic agent. This method induces degradation of cPAA into defined substituted glutarimide derivates, as specific pyrolysis products. These pyrolysis products appeared in typical pattern of homologues allowing not only an unambiguous identification of the polymer but, more important, also a reliable pyrolysis based quantification in environmental concentration levels. Pyrolysis analysis were carried out on pure cPAA and spiked samples for method optimization, as well as on four sewage sludge samples from Germany as proof of applicability. All four specific degradation products were identified in three out of four sewage sludge samples indicating that the developed TMAH-thermochemolysis method is suitable for PAA detection in complex matrices and on environmentally relevant concentration levels. Nevertheless, experiments on sewage sludge samples revealed cPAA contamination in a concentration range between 29 and 76 μg/g. However, it has to be noted that the presence of all four specific degradation products has to be validated in order to have a doubtless cPAA confirmation in environmental samples.

Keywords

• Glutarimide
• Off-line thermochemolysis
• Polyacrylamide
• Sewage sludge