Liquid-liquid-liquid phase microextraction of aromatic amines in water using crown ethers by high-performance liquid...

Liquid-liquid-liquid phase microextraction (LLLME) coupled with high-performance liquid chromatography (HPLC) for the analysis of some aromatic amines is described. These compounds were extracted from 4.0mL aqueous sample that adjusted to pH 13 with, NaOH-NaCl buffer solution (donor phase, P(1)) into an organic phase (P(2)) 150mul benzyl alcohol and ethyl acetate (2:1) and then back extracted into a microdrop of aqueous acceptor phase (P(3)), adjusted at pH 2, with Na(2)HPO(4)-H(3)PO(4) buffer solution. The extraction time, T(1) (from P(1) to P(2)) was 20min and T(2) (from P(2) to P(3)) was 1min. Different crown ethers as complexing agents for amines were added to the acceptor phase to improve the extraction time. Factors such as organic solvents, extraction times, and addition of crown ethers to acceptor phase and stirring rate were optimised. The method was applied for determination of aromatic amines in wastewater samples. Enrichment factors ranged from 184.5 to 389.7. The linearity range was from 3 to 1000ng/ml and the detection limits varied from 0.8 to 1.80ng/ml. Relative standard deviations (%, n=5) were found (at S/N 3) in the range of 1.9 to 10.1. All experiments were carried out at room temperature, 22+/-0.5 degrees C.