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A novel chemiluminescence assay of organophosphorous pesticide quinalphos residue in vegetable with luminol detection

DOI: 10.1186/1752-153x-4-13

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The CL method for the determination of organophosphorous pesticide quinalphos is based on the phenomenon that quinalphos can apparently enhance the CL intensity of the luminol-H2O2 system. The optimal conditions were: luminol concentration 5.0 × 10-4 mol/L, H2O2 concentration 0.05 mol/L.pH value 13. In order to restrain the interference from metal ions, 1.0 × 10-3 mol/L of EDTA was added to the luminol solution. The possible mechanism was proposed.Under the optimum reaction conditions, CL was linear with the concentration of quinalphos in the range of 0.02 μg/mL -1.0 μg/mL and the detection limit was 0.0055 μg/mL (3σ). This method has been successfully applied to the detection of quinalphos in vegetable samples. According to the experimental data, the average recoveries for quinalphos in cherry tomato and green pepper 97.20% and 90.13%. Meanwhile, the possible mechanism was proposed.Organophosphorus pesticides are widely used in agriculture due to their high insecticidal activity[1]. They are toxic organic chemicals which can irreversibly inhibit acetylcholinesterase (AChE) which is essential for the function of the central nervous system [2,3]. As the pesticide residue is a potentially serious hazard to human health, the control and detection of pesticide residue plays a very important role in minimising risk[4]. Many methods have been developed in the last few years for the detection of organophosphorus pesticides. The most widely used methods are gas chromatography (GC) [5-7], high-performance liquid chromatography (HPLC) [8,9], gas chromatography-mass spectrometry(GC-MS) [10], immune assay and fluorescence [11,12]. These methods are accurate and selective, but they require relatively expensive instrumentation and skilled technicians.Chemiluminescence (CL) is defined as the production of electromagnetic radiation (ultraviolet, visible or infrared) observed when a chemical reaction yields an electronically excited intermediate or end product, which either luminesc


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