Melamine s high rich nitrogen content is about

Melamine’s high-rich nitrogen content is about 66% by mass. When, it is illegally added into dairy products by unethical company to obtain incorrectly high readout of apparent protein content, it is measured by the conventional standard Kjeldahl test [6]. In March 2007, melamine came to public attention in North America when there are two cases reported involving the addition of melamine and its analogues in pet foods. Consequently, a pet food manufacturer alerted the US Food and Drug administration to animal deaths associated with the deaths of dogs and cats in the US that appeared in certain batches of their pet food. In the following months, consumers and veterinarians again reported more illnesses and deaths potentially associated with pet food [7–9]. In early September 2008, about 294,000 children from China are diagnosed with urinary tract stone with 50,000 infants being hospitalised and resulting in six babies’ death due to the melamine contamination in milk products [10,11]. High concentration ingestion of melamine has proven to be toxic to humans and found in the formation of insoluble melamine cyanurate crystals in kidneys causing renal failure. For this reason, there is increasing demand to find effective and reliable method for the analysis of melamine in milk and other food products. During the past decades, several analytical methods have been applied for the determination of melamine in food products such as high-performance liquid chromatography (HPLC) [12,13], gas chromatography–mass chromatography (GC–MS) and liquid chromatography–tandem mass chromatography (LC–MS–MS) [14–16]. However, most of these methods are complicated preconcentration, time-consuming steps and required expensive instruments. Advances in chemistry, physics, ambroxol hydrochloride and molecular biology have led to the development of an electrochemical sensor, which can able to detect a wide range of biological elements due to their simplicity, low cost, sensitivity, selectivity, and possibility for miniaturization, portability and integration in automated devices [17]. Thus, nanomaterials and nanocomposite membrane based developed-electrochemical biosensor are needed in a small amount of sample for rapid detection of melamine. Chitosan (CHIT) is an interesting natural biopolymer that contains reactive amino and hydroxyl functional groups. It has been widely used for immobilization due to high ease of use and absorption, excellent film-forming ability, high permeability, high heat-stability, mechanical strength, non-toxicity, biocompatibility, low cost and easy availability. Moreover, chemical modification of the amino groups of CHIT has provided hydrophilic environment for the biomolecules. It is soluble in diverse acids that the interaction with polyanions to form complexes and gels [18–21]. However, hybrid materials based on CHIT have been used in development of conducting polymers, carbon nanotubes, redox mediators, metal nanoparticles and oxide agents, due to excellent properties of individual components and outstanding synergistic effects simultaneously for electrochemical biosensing platforms [22,23]. With advent of nanotechnology, nanoparticles (NPs) have attracted much attention due to their novel optical, electrical, and mechanical properties. Amongst various NPs, calcium oxide nanoparticles (CaONPs) have obtained considerable attention because they are non-corrosive, non-explosive, non-volatile, high basicity and eco-friendly. CaONPs have only required mild reaction conditions to produce high yields of products in short reaction times when compared to traditional catalysts [24–27]. Ionic liquids (ILs) are salts with melting point below 100°C. they have been used during the past decade due to their unique properties, such as high chemical and thermal stability, relatively high ionic conductivity, low vapour pressure, wide liquid range and large electrochemical windows [28,29]. ILs are usually used in homogeneous catalytic reactions because they high catalytic activity and good selectivity. It is not only used for supporting electrolyte, but also used as the modifier in chemically modified electrodes in the biosensor field [30].