was the DI and x was the cloxacillin sodium concentration in
mg L1. The detection limits (3r) of the luminol–H2O2, luminol–
H2O2–Cu2+ and luminol–H2O2–CuO nanosheets CL systems were
calculated to be 0.238, 0.276, and 0.026 mg L1, respectively. The
relative standard deviation (RSD%) for the eleven determinations
of 0.05, 1.00 and 4.00 mg L1 cloxacillin sodium with luminal–
H2O2–CuO nanosheets was 2.25%, 1.9% and 2.21%. Also, the RSD%
for the eleven determinations of 4.00 mg L1 cloxacillin sodium
with luminal–H2O2–Cu2+ was 3.68% and the RSD% for the eleven
determinations of 4.00 mg L1 cloxacillin sodium with luminal–
H2O2 was 3.18%. Comparison of the analytical performances of
these three systems corroborated