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Abstract
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Background: Bisphenol A (BPA) is found in most of the water sources around the world and its toxicity is widely reported in literature [1]. Hence, it is very important to determine it in water samples as a substance that is related to human health. Among conventional analytical methods, chemiluminescence (CL) methods have attracted many attentions because of a number of advantages, such as simplicity of the instrumentation, low operating costs, high sensitivity, wide linear range and the high selectivity [2]. The present work aimed to provide a new, simple, precise and efficient method based on layered double hydroxide (LDH)–assisted photogeneration of reactive oxygen species (ROS) as oxidants in luminol-based CL system for sensitive and selective detection of BPA in water samples. Methods: The CoZnAl LDH was prepared by a co-precipitation method and characterized via X-ray diffraction analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and diffuse reflectance spectroscopy. Several parameters affecting the analytical signal such as concentrations of luminol, NaOH and LDH as well as irradiation time were optimized. For CL measurements, an aliquot of 500 µL CoZnAl LDH sol solution and appropriate volume of real sample or standard solution were transferred into the CL cell and volume was reached to 2.0 mL with deionized water. Then, light irradiation of the mixture was carried out for 5 min under stirring. Finally, the CL reaction was progressed by injection of 1.0 mL of 1.5 × 10‒3 mol L−1 luminol solution into the reaction cell and recording of CL intensity-time profiles at λ=425 nm.
Results: This simple CL approach showed a limit of detection of 30 pg mL‒1 and exhibited a linear response in the concentration range from 0.1 to 20 ng mL‒1. The intra- and inter-day relative standard deviations were 2.7% and 4.1%, respectively and relative recovery values were obtained between 97.3 and 104.6% for the spiked water samples.
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