Designing and construction of polymer and polymer based composite materials as an electrochemical interface becoming the promising area of research in the era of electro and electroanalytical chemistry [1–4]. Many polymers have been used for the construction of polymer based electrochemical interfaces which includes polyaniline, polypyrrole, polyindol, polythiophene, poly (o-toluidine), para phenylene diamine etc.. The extended interest on these polymers is owing to its porous surface structure, large surface area, good adsorption capacity, electrical, corrosion, electrochemical and electrocatalytic properties [5–7].
The polymer modified electrodes have been extensively used in the fabrication of energy storage devices, computer chips, sensors, biosensors, screen printed electrodes [3, 5 & 6]. Among the various applications, the development of sensors and bio sensors have been studied extensively due to easy of its fabrication. Even though, these electrodes can sense many analytes at reliable concentration levels but suffers from high overpotential and low detection limits due to lack of interacting ability of polymer and analyte molecules [8]. In order to improve these drawbacks, efforts have put forword to achieve low over potential and very low detection limits by modifying the surface structure of polymers with metal particles like Au, Pt, Pd, Cu, Co, Ni, Sn, Zn etc.. through various synthetic routes. This modification improvises the electrode performance and is attributed due to the uniform dispersion of metal particles on the large surface area of polymer matrices [9]. Out of many metals, Sn particles have attained gaint industrial applications due to its good adherence, uniform and smooth deposition on the surfaces, corrosion resistance property and appreciable electrochemical behaviour [10]. Among polymers, PANI has gained lots of interest due to pi - conjugation, its diverse electrical, structural, optical properties and more importantly ease of deposition onto any surface [11]. The existing methodologies for the synthesis of polymer - metal composites involves extended chemical procedures, prolonged time and the use of highly hazardous and toxic chemicals as oxidising and reducing agents [12 & 13]. Hence, there is a substantial need for the development of an easy and environmental friendly method for its synthesis.
Hydrazine is considered as one of the good efficient fuel in rocket system. Now a days, in addition to its fuel application it has been widely used in various fields such as industrial, agriculture, pharmacological, military, aerospace spaces, pesticides, pharmaceutical intermediates, metal film manufactures, photographic chemical, reducing agent, flowing agent, corrosion inhibitor and so on [14]. Hydrazine is well known to be highly toxic and hence it its prolonged exposure even at trace concentration levels may pose adverse health effect such as liver, brain, DNA damage, creation of blood abnormalities, and irreversible deterioration of nervous system. In addition to this, it has been listed as one of the carcinogenic materials by the U.S. Environmental Protecting Agency [15]. As a result of this, its determination at low concentration level plays a very important role in the area of environmental and also in electroanalytical chemistry.
In view of this, many methods have been developed for the analytical quantification of hydrazine which includes luminescence, spectrophotometry, capillary electrophoresis, spectro-fluorimetry, high performance liquid chromatography (HPLC), flow-injection analysis and gas chromatography. Even though these methods have been proven to be highly sensitive and accurate but are laboratory based, require expert to operate, day to day maintenance cost, prolonged sample preparation. Hence, there is a pressing need for the a method which should be very simple, affordable, selective, sensitive, rapid and mainly field applicable. One such method is electrochemical method, which has widespread utilization in analytical chemistry and it offers the above said advantages [16–20].
Therefore, in the present work we developed a green methodology for the synthesis of polymer - metal composite material at ambient conditions without using any external oxidizing agents and any prolonged and harsh experimental conditions. Further, it has been used in the amperometric determination of hydrazine at trace concentration levels. The electrochemical studies revealed that the proposed new electrochemical sensor showed excellent electrocatalytic activity towards to oxidize hydrazine electrocatalytically with considerable advantages like operational simplicity, higher sensitivity, prolonged stability, good reproducibility. Furthermore, the introduced electrochemical interface has been substantially employed in the detection of hydrazine from tap water. From the survey of literature this methodology for the fabrication of PANI - Sn composite and its subsequent application towards N2H4 detection has not been reported elsewhere this in turn leads to the novelty of present work.