ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Graphite-on-paper-based resistive sensing device for aqueous chemical identification

Reza Rashidi, Jasem Alenezi, Jennifer Czechowski, Justin Niver, and Sulaiman Mohammad

State University of New York, Alfred, USA

E-mail: rashidr@alfredstate.edu

Abstract: This article exhibits an innovative, low-cost, and environmentally friendly sensor for identifying aqueous chemicals. The sensor is able to distinguish between different varieties of chemicals including acids, bases, deionized water, and solvents. The sensing device can be used in a wide range of industrial applications that require low-cost, accurate methods of chemical detection. The device can identify different chemicals based on changes in the electrical resistance of graphite which is used as a sensing element. A graphite line was drawn on a sheet of paper using a pencil that was used as the test strip and placed in a custom-made test fixture, providing a controlled environment once the graphite test strip was in contact with electrical contacts mounted in the fixture. The electrical contacts of the fixture were connected to a data acquisition device which measured and recorded voltage outputs using LabVIEW software. The data collected were then used to compute the electrical resistance. The solvent analysed in this research was isopropyl alcohol. The acids analysed were nitric acid, sulphuric acid, hydrochloric acid, and hydrogen peroxide. The base analysed was ammonium hydroxide. Tests were performed by placing two droplets of each chemical onto the paper through an inlet hole located at the top of the test fixture. All tests were performed at a constant temperature. The electrical voltage was recorded every millisecond once the chemical was dropped onto the test strip through the hole in the test fixture. Electrical resistance versus time plots displayed a unique curve for each chemical analysed which may be used for chemical identification.

Keywords: Chemical sensing device ; Chemical sensor ; Instrumentation ; Graphite-on-paper ; Chemical identification ; Chemical detection 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00836-4

Chemical Papers 73 (11) 2845–2855 (2019)