shows the UV–Vis absorption spectra of luminol–H2O2 in the
absence of CuO nanosheets. As shown in Fig. 5 and 5 mg L1 cloxacillin
sodium had no absorption peak in the studied wavelength
range. Also, it could be seen that luminol–H2O2 reaction had two
absorption peaks at about 301 and 351 nm. Fig. 5 indicates that,
the absorption spectrum of solution containing the CuO nanosheets,
luminol and H2O2 is approximately similar to the absorption
spectrum of the luminol–H2O2 system; this implies that no
chemical interaction happened between luminol–H2O2 and CuO
nanosheets. Moreover, Fig. 5 shows that the absorption of solution
containing the luminol, H2O2 and CuO nanosheets in the range of
301–351 nm is reduced in the presence of cloxacillin sodium. This
shows that, when cloxacillin sodium was injected into the luminol–
H2O2–CuO nanosheets CL system, the cloxacillin sodium competes
with luminol for reacting with OH radicals. This leads to the
decrease of the absorption peak at 301 and 351 nm due to the
decrease in the concentration of H2O2.
Fig. 6 demonstrates the CL emission