It has been reported that NiS nanoparticles (NPs) can markedly enhance light emis- sion from the chemiluminescence (CL) reaction of luminol–O2 (λmax = 425 nm). Addi- tionally, it was shown that cephalexin (CEF) could further increase the intensity of light emitted from the NiS NPs–luminol–O2 CL reaction. Inspired by these findings, we aimed to develop a new and straightforward CL method for the determination of CEF. A calibration graph over the range 1.00 10 6 to 4.00 10 5 mol L 1 was established. The limit of detection of the CL method was 8.00 10 7 mol L 1. The coefficient of variation of the CL method was 2.20% (n = 6) for the measurement of 6.00 10 6 mol L 1 CEF. NiS NPs were produced by exploiting the precipitation method and identified using several spectroscopic approaches. The proposed CL method was successfully used to measure CEF in some pharmaceutical products and in spiked human serum. The chemical mechanism governing the CL reaction was briefly explained.
