Capillary electrophoresis microchips with thick-film amperometric detectors: separation and detection of phenolic compounds

A miniaturized analytical system for separating and detecting toxic phenoli c compounds, based on the coupling of a micromachined capillary electrophor esis (CE) chip with a thick-film amperometric detector is described. The in tegrated microsystem offers a rapid (4 min) simultaneous measurement of sev en priority chlorophenolic pollutants. Such compounds could be detected dow n to the 1x10(-6)-2x10(-6) M level, with linearity up to the 2x10(-4) M lev el examined. The highly stable response observed for repetitive injections (R.S.D. = 3.7%, n = 20) reflects the negligible surface passivation due to the injection of extremely small sample volumes. Additional phenols were se parated and detected upon raising the pH of the running buffer from 8.0 to 10.5. Applicability to river water samples is demonstrated. While the conce pt of miniaturized separation/detection systems is presented within the fra mework of phenolic contaminants, such devices should be attractive for fiel d monitoring of other classes of priority contaminants. The development of fast-responding miniaturized systems with negligible waste production holds particular promise for meeting the requirements of field 'Green Analytical Chemistry'. (C) 2000 Elsevier Science B.V. All rights reserved.