Abstract: For the determination of primary alkylamines in the presence of secondary alkylamines, samples were subjected to HPLC on a column (15 cm x 4.6 mm) of a styrene - divinylbenzene copolymer (5 µm) with methanol as mobile phase (0.5 mL min-1). Primary amines in the eluate were derivatized at 45°C with 58 mM phthalaldehyde and 58 mM 2-mercaptoethanol in ethyl acetate (0.5 mL min-1), the solution was mixed with ethyl acetate (0.5 mL min-1) in two knitted PTFE tubes (100 cm x 0.8 mm) and the fluorescence was measured at 431 nm in a 7 µL flow cell (excitation at 340 nm). The detection limit of decylamine was 0.18 mM. Procedures are also described for the selective determination of secondary amines [by derivatization with 7-chloro-4-nitrobenzofurazan and fluorimetry at 525 nm (excitation at 480 nm)] after masking of primary amines and for non-selective determination of primary and secondary amines. The procedures were used to analyze Synprolam 35DM surfactant, containing 98% of tertiary amines and 1% each of primary and secondary amines.

Abstract: Amines were separated by HPLC on an Aminex HPX-72-0 column (30 cm x 7.8 mm i.d.) with 75 mM NaOH as mobile phase (0.75 ml/min) and amperometric detection at 0.4 V vs. Ag/AgCl using a Co working electrode. Results were compared with those obtained using a Cu electrode. FIA experiments were also performed using 75 mM NaOH as carrier (0.75 ml/min). The addition of organic modifier did not improve the results. The RSD n = 10) was 1.3% for 12 nmol methylamine. The electrode response was stable for 3-4 days. Separation of six amines was achieved using the HPLC method with retention time RSD of Calibration graphs were linear for 30 (for benzylamine) to 300 (methylamine) times the limit of detection (6.3 and 0.5 nmol, respectively).

Abstract: Sample was injected into a stream of borate buffer (pH 11.0), which merged first with 1 mM rhodamine B and then with 1.64 mM NaOCl (all at 1 mL min-1); detection of chemiluminescence was by a photomultiplier tube. The calibration graph for triethylamine was rectilinear for 0.2 mM in water and 0.1 mM in seawater. Coefficients of variation were generally 2% (n = 5). The method can also be used to determine trimethyl- and tripropyl-amine. Quenching of the chemiluminescence occurs in the presence of a 10-fold excess of diethylamine or ethylamine.

Abstract: The development of a detection method based on the electrogenerated chemiluminescence of the cited reagent (I), immobilized in a Nafion film coated on an electrode is described. Control of the electrode potential controls creation of the reactive reagent (I) which reacts with certain analytes to yield chemiluminescence intensity which is proportional to the analyte concentration. The sensor was applied to the FIA determination of oxalate, alkylamines and NADH with detection limits of 1 µM, 10 nM and 1 µM, respectively; working ranges extended over four orders of magnitude. Sensitivity was constant over pH 3 to 10 and emission intensities increased with temperature The sensor remained stable for several days with suitable storage condition. The development of a detection method based on the electrogenerated chemiluminescence of tris(2,2'-bipyridine)ruthenium( II), (Ru(bpy)3(2+], immobilized in a Nafion film coated on an electrode is discussed. Control of the electrode potential controls creation of the reactive reagent Ru(bpy)3(3+) which reacts with certain analytes to yield chemiluminescence emission of intensity proportional to the analyte concentration. The reaction results in Ru(bpy)3(3+) being converted to Ru(bpy)3(2+), which then is recycled to Ru(bpy)3(3+) again at the electrode. This sensor has been used in flow injection to determine oxalate, alkylamines, and NADH. Detection limits are 1 µM, 10 nM, and 1 µM, respectively, with working ranges extending over 4 decades in concentration. Sensitivity is constant over the wide pH range from 3 to 10. With oxalate, and to a small extent with amines, emission intensities increase with increasing ionic strength; this was shown to be a phenomenon related to the Nafion film and not to the chemiluminescence reaction. Emission intensities increase with temperature. The sensor remains stable for several days with suitable storage conditions. Significant amounts of Ru(bpy)3(3+) are shown to be capable of storage within the film.