Automated Flow Injection Analyzer with On-Line Solid-Phase Extraction and Chemiluminescence Detection for the Determination of Dodecylamine in Diesel Fuels

This paper describes the development of a portable, automated flow injection-chemiluminescence (FI-CL) analyzer incorporating on-line solid-phase extraction (SPE) for the determination of dodecylamine (detergent) in diesel fuels. The method is based on the peroxyoxalate/sulforhodamine 101 chemiluminescence reaction, with SPE required to remove indigenous compounds within the diesel fuel matrix that interfere with the CL response. The automated analyzer achieved a detection limit of 2.9 mg L-1 and a linear range of 2.9-50 mg L-1, which was suitable for determinations of dodecylamine at levels typically present in fully formulated diesel fuels (40 mg L-1). Analyses of base fuels from five different sources demonstrated that an automated FI-CL-SPE system could provide a portable instrument for monitoring the presence/absence of dodecylamine in diesel fuels.