Large-volume sample stacking for the analysis of low molecular mass amines in steam water by CE using novel highly absorbing probe for indirect UV detection

A rapid, simple, sensitive and ultrafast capillary electrophoretic method - large-volume sample stacking (LVSS) without a polarity switching step has been developed in this study for determining ammonia and 9 amines, including ethanolamine, cyclohexylamine, hydrazine, morpholine, triethanolamine, and dimethylamine in steam water and their degradation products, such as methylamine, ethylamine, diethanolamine, and ammonia. The background electrolyte (BGE) containing acridine as a probe was firstly used for indirect UV detection. Acridine was shown to be very beneficial for the determination of low molecular mass amines due to its high electrophoretic mobility and at the same time high molar absorption coefficient (ε252) of 1.7 ∗ 105. No laborious sample preparation was needed. Separation and detection was achieved in about 8.5 min for BGE containing acridine per sample. Limits of detection (LOD) using acridine were as low as 0.003 mg/L. The calibration plots showed good linearity over the concentration range from 0.01 to 1 mg/L for ammonia and the amines of interest for nuclear and thermal power plants. The proposed method was successfully applied to the determination of ethanolamine and cyclohexylamine in steam water samples obtained from thermal power plant and the analytical results were in good agreement with those obtained by reference ion chromatography (IC) method.