Vol.:(0123456789) 1 3 Journal of the Iranian Chemical Society https://doi.org/10.1007/s13738-018-1459-z ORIGINAL PAPER Imprinted Azorubine electrochemical sensor based upon composition of MnO 2 and 1-naphthylamine on graphite nanopowder Somayyeh Piri 1  · Farideh Piri 1  · Mohammad Reza Yaftian 1  · Abbasali Zamani 2 Received: 10 April 2018 / Accepted: 26 July 2018 © Iranian Chemical Society 2018 Abstract A new sensitive and selective molecularly imprinted electrochemical sensor was developed for Azorubine determination. This sensor was based on molecularly imprinted polymer composed of poly(1-naphthylamine), triphenylamine (as cross-linkers) and dispersed MnO 2 nanorod particles on graphite nanopowders. The structure of the prepared nanocomposite was char- acterized by X-ray powder difraction, energy-dispersive X-ray spectroscopy, feld emission scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. Calibration curve of the imprinted sensor was linear in the concentration range 1–12 mg L − 1 with a detection limit of 0.57 mg L − 1 . The application of the sensor was checked by the determination of Azorubine in a water sample. Keywords Poly(1-naphthylamine) · Nanomanganese oxide · Graphite nanopowder · Molecularly imprinted nanocomposite · Electrochemical sensor · Azorubine Introduction Natural and synthetic colors are extensively used in various food and cosmetic industries. Since natural food colors are relatively unstable and are more expensive than synthetic ones [1], a great amount of synthetic dyes are currently con- sumed in a variety of foods, drinks, candies, and sweets [2]. Although azo dyes are the largest group of dyes used in more than half of the global dye productions [3], some of them have been confrmed to be genetically toxic [4]. The permitted amount of these dyes is strictly regulated because of their potential risk to human health. The lists of permitted food colors vary from country to country [5]. Thus, monitor- ing and controlling the levels of dyes in food stufs are of paramount importance [6, 7]. A great number of analytical techniques have frequently been used for the determination of food colorings [8–16]. These techniques include spectrophotometric methods [8, 9], thin-layer chromatography [10], voltammetry [11], polar- ography [12], capillary electrophoresis [13], ion chromatog- raphy [14], and high-performance liquid chromatography [15, 16]. However, some of these methods lack selectivity, need to complicated pretreatment and/or require relatively expensive apparatus. The selective attitude of molecularly imprinted poly- mers (MIPs) allowed these materials to have recently been accepted widely as new prominent molecular recognition materials for preparing chemical sensors [17–22]. Their advantages such as stability, low cost and easy producibility relative to the similar biological species used in biosensors including antibodies and enzymes are among the highlighted characteristics of MIP-based sensors [20, 23, 24]. Various chemical sensors have been prepared using MIPs for molecular recognition followed by appropriate signal transductions such as impedimetric [25], potentiometric [26], voltammetry [27] and quartz crystal microbalance [28] techniques. Since electrochemical techniques allow sensitive, simple and inexpensive detection of a variety of analytes, it would be a promising alternative for dye analysis in food samples [12, 29–32]. Azorubine (disodium 4-hydroxy-3-(4-sulfonato- 1-naphthylazo)-1-naphthalenesulfonate), named also Car- moisine, is an authorized food color, often used in European countries, but it is considered a violation in Norway, Sweden * Mohammad Reza Yaftian yaftian@znu.ac.ir 1 Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Islamic Republic of Iran 2 Department of Environmental Science, Faculty of Science, University of Zanjan, Zanjan 45371-38791, Islamic Republic of Iran