Chemiluminescence detection in flow injection analysis and liquid chromatography
This thesis describes the development of chemiluminescence procedures for the detection of some organic compounds of interest to the oil industry. Water soluble tertiary amines were determined using flow-injection analysis with chemiluminescence detection. The chemiluminescence was generated by reacting the aqueous tertiary amine solution with aqueous sodium hypochlorite at pH 11.0, in the presence of rhodamine B, which sensitizes the emission. The simplex optimized flow-injection manifold was used to determine trimethylamine, triethylamine and tripropylamine in water and sea water. A standard-addition calibration procedure was used to determine trimethylamine in an industrial scrubbing medium. The chemiluminescence of tertiary amines was extended to the detection of the non-ionic surfactant, Nonidet AT 85, which contains a tertiary amine group. The flow-injection manifold was simplex optimised for this analyte in sea water. The surfactant was also determined in aqueous extracts of marine sediment. Calibration was by a standard addition procedure. Primary amines were determined by flow-injection analysis after fluorimetric derivatization with o-phthalaldehyde and 2-mercaptoethanol in non-aqueous media. The fluorescent derivative was detected by excitation using the peroxyoxalate chemi-excitation reaction. A pre-column fluorimetric derivatization procedure was developed for the determination of carboxylic acids in non-aqueous media. Straight chain acids over the range C2 to C20 and benzoic acid were derivatized with 9-anthracene methanol, using dicyclohexylcarbodiimide (DCC) as a coupling reagent to yield fluorescent esters. Separation was carried out by reversed-phase high-performance liquid chromatography and the peroxyoxalate chemi-excitation reaction was used to detect the fluorescent species. An automated flow-injection manifold was developed, including computerised data acquisition and automated sample uptake and injection. This enabled the system to operate whilst unattended. The precision of the data was higher than that obtained with the manual system. Finally, a flow-injection manifold was designed which incorporated a monochromator between the flow cell and the detector, thus enabling chemiluminescence spectra to be obtained.