Quantum Dots and Double Surfactant-Co-modified Electromembrane Extraction of Polar Aliphatic Bioamines in Water Samples Followed by Capillary Electrophoresis with Contactless Conductivity Detection

Efficient enrichment of aliphatic bioamines is still a challenge due to their high polarity. In this work, a novel electromembrane extraction method co-modified with quantum dots, bis(2-ethylhexyl) phosphate and trioctyl phosphate (QDs-DEHP-TEHP@EME), was firstly developed for purification and enrichment of four typical aliphatic bioamines, and the extract was directly injected for electrophoretic separation and contactless conductivity detection. The main experimental parameters influencing separation and extraction efficiency were investigated and optimized in detail. Under the optimum conditions, the four target analytes could be baseline separated from the main potential coexisting substances (five common inorganic cations, two aromatic bioamines, and two heterocyclic bioamines). Furthermore, the limits of detection in the sample matrix could reach 0.060-6.0 mu g L-1 (S/N = 3) based on the synergistic enrichment effect of field amplified stacking injection (FASI), and the corresponding enrichment factors reached 30-1853 times. This developed method has been successfully used for the sample analyses of tap and bottled drinking water, and the average recoveries were in the range of 80.0-117%. In brief, off-line QDs-DEHP-TEHP@EME and on-line FASI offer an efficient enrichment for the four polar aliphatic bioamines, and contactless conductivity detection method needs no derivatization. This proposed method provides an alternative for the polar bioamines in the real-world water quality analysis.