Surface interaction of copper phthalocyanine modified single walled carbon nanotubes with pesticides

Hybrid materials were produced by mixing tetrakis(hexadecylthio) substituted copper(II) phthalocyanine (CuPcR4) with acidified single-walled carbon nanotubes (SWCNTs) and they were characterised by UV-vis absorption spectroscopy, scanning electron microscopy and atomic force microscopy. Thin films of pristine CuPcR4 and CuPcR4/SWCNT were prepared by spin coating onto gold-coated glass slides and applied as active layers to detect pentachlorophenol (PCP), 2-chlorophenol, diuron and simazine in water utilising total internal reflection ellipsometry (TIRE) as an optical detection method. Different concentrations of pesticides in water ranging from 1 to 25 μg/L have been examined in the current work. It is revealed that the shifts in Δ(λ) spectra of CuPcR4/SWCNT films were evidently larger than those produced by the pristine CuPcR4 films, indicating largely improved films' sensitivity of the hybrid films. The sensitivity has been calculated according to the phase shift in the Δ(λ) spectra. The higher sensitivity was found to be 0.00396/(μg/L) towards PCP in case of CuPcR4/SWCNT sensor. The lower detection limit has been calculated to be 840 ng/L.