A passive solid sensor for in-situ colorimetric estimation of the presence of ketamine in illicit drug samples

• DOI: 10.1016/j.snb.2017.07.183
• Publication Date: 2017-07-26T19:17:30Z
• Authors: A. Argente-García; N. Jornet-Martínez; R. Herráez-Hernández; P. Campíns-Falcó
• Keywords: Polydimethylsiloxane; Absorbance; Attenuated total reflection

Abstract A colorimetric sensor has been developed for the presumptive detection of ketamine in illicit drug samples. The sensor has been prepared by immobilized the reagent Co(SCN) 2 into polydimethylsiloxane (PDMS). When exposed to solutions of ketamine at a basic pH, the sensor color changes from brown to blue-purple due to the diffusion of the analyte molecules to the polymeric matrix and subsequent interaction with the reagent particles. The sensor enables the visual identification of amounts of drug as low as 30 μg in a few minutes. Quantification of ketamine is also possible through the measurement of the absorbance in diffuse reflectance mode. Under the proposed conditions, linear response was obtained up to concentrations of the ketamine of 1000 μg/mL (4.21 mM) with satisfactory precision (relative standard deviations, RDSs