The Application of Ion Selective Electrode Modified with Molecularly Imprinted Polymer based on Liquid Membrane for the Determination ofMethylmercury in Real Samples

Recent years have seen increased interest in molecular imprinting technology. Molecular imprinted polymers (MIPs) have become an important tool in the preparation of artificial and robust recognition materials capable of mimicking natural systems [1].Molecular imprinted polymers (MIPs), described as artificial locks for molecular keys , have the ability to recognize the used template from a mixture of closely related compounds. Due to the molecularrecognition ability, MIPs have been proposed for promising applications in a wide variety of fields, such as chemical/biological sensors, chiral separation, catalyst, and solid-phase extraction [2].Mercury is considered to be a major environmental pollutant on a global scale.Environmental and health risks for mercury are caused by methyl mercury that is formed by bio methylation of mercury (II) which is carried out by microorganisms in sediment and soil. Methylmercury concentrations, however, usually does not exceed 1.5% of the total mercury content in sediments. Methyl mercury binds strongly with biological ligands containing sulfhydryl groups affecting the function of enzymes and interfering with protein synthesis. It is a neurotoxin thatreadily crosses bio- logical membranes and accumulates to harmful concentrations in organisms and biomagnifies in aquatic food webs to concentrations of toxicological concern [3]. Until now methods such as using cold vapor atomic absorption, thermal analysis, and absorption of X-rayshave been used to measure methyl mercury. In this study a membrane electrode based on molecularly imprinted polymer were designed and prepared. The best response characteristics were obtained using the composition: 20%molecularly imprinted polymer as ionophore, 50% dibutyl phthalate as plasticizer and 30% polyvinyl chloride.The electrode exhibited a near Nernstian response of 60 mV/decade over the activity range 1×10-2 to 1 × 10-5 M.The operational pH range of the sensor is 4.0–8.0. The electrode shows a response time of 20 s and can be used for at least five weeks without any considerable divergence in potentials. It exhibits very good selectivity relative to a wide varietyof alkali, alkaline earth, transition and heavy metal ions. The proposed electrode used as determining methylmercury in real examples like canned tuna, cow milk and wastewater based on calibration graph

کلیدواژه ها:

Mercury ، Molecular imprinted polymers ، Molecular keys ، Biological sensors