On‐site detection of phosgene agents by surface‐enhanced Raman spectroscopy coupled with a chemical transformation approach

Phosgene and its analogs are greatly harmful to the public health, environmental safety and homeland security as widely used industrial substances with extremely high toxicity. In order to rapidly evaluate the emergency risk caused by these chemicals, a new highly sensitive method based on surface-enhanced Raman spectroscopy (SERS) technique for measurement of phosgene agents was developed for the first time. Coupled with a chemical transformation approach, the highly toxic phosgene was conveniently converted to a SERS-sensitive probe, i.e. iodine (I2), with low toxicity or non-toxicity. The characteristic SERS peak in 459 cm−1 was used for quantitation and was presumed as a formation of triiodide anion (I3−), which was induced in an iodide (I−)-aggregation Au NPs system. The total measurement can be completed in ~20 min with the limits of detection of ~60 µg/l (phosgene) and ~30 µg/l (diphosgene), respectively, on a portable Raman spectrometer. This work is the first report of SERS measurement on phosgene and diphosgene in a quantitative level. This method is expected to meet the requirements of on-site detection of phosgene agents, promote emergency responses and raise more opportunities for the portable SERS applications. Copyright © 2015 John Wiley & Sons, Ltd.