Measurement of Nitrogen Mustard Degradation Products by Poly(dimethylsiloxane) Microchip Electrophoresis with Contactless Conductivity Detection

A poly(dimethylsiloxane) (PDMS) microfluidic device with contactless conductivity detection for the determination of nitrogen mustard degradation products is reported. Three alkyl ethanolamines: N ‐methyldiethanolamine (MDEA), N ‐ethyldiethanolamine (EDEA), and triethanolamine (TEA), (degradation/ precursor products of HN‐1, HN‐2 and HN‐3 blister agents) were analyzed by microchip capillary electrophoresis (CE). The original PDMS channel was coated by poly(ethyleneimine) (PEI) to improve the separation of three ethanolamines. Experimental conditions for the separation and detection processes have been optimized to yield well defined separation and high sensitivity. The response times for the three ethanolamines were less than 5 min., the detection limits were 2.0–4.0 mg L −1 and the relative standard derivations for the migration times and peak heights were 1.6–2.3% and 4.1–5.7%, respectively. The linearity of calibration for each of the compounds was as follows: MDEA, r 2 =0.970; EDEA, r 2 =0.994; TEA, r 2 =0.988. Applicability of this method for natural (lake and tap) water samples was also demonstrated. Compared to conventional analytical methods, this miniaturized system offers promise for on‐site monitoring of degradation products of the nitrogen mustard class of chemical warfare agents, with advantages of cost‐effective construction, simple operation, portability, and small required sample volumes.