Issue 47, 2020

Cocaine by-product detection with metal oxide semiconductor sensor arrays


A range of n-type and p-type metal oxide semiconductor gas sensors based on SnO2 and Cr2O3 materials have been modified with zeolites H-ZSM-5, Na-A and H–Y to create a gas sensor array able to successfully detect a cocaine by-product, methyl benzoate, which is commonly targeted by detection dogs. Exposure to vapours was carried out with eleven sensors. Upon data analysis, four of these that offered promising qualities for detection were subsequently selected to understand whether machine learning methods would enable successful and accurate classification of gases. The capability of discrimination of the four sensor array was assessed against nine different vapours of interest; methyl benzoate, ethane, ethanol, nitrogen dioxide, ammonia, acetone, propane, butane, and toluene. When using the polykernel function (C = 200) in the Weka software – and just five seconds into the gas injection – the model was 94.1% accurate in successfully classifying the data. Although further work is necessary to bring the sensors to a standard of detection that is competitive with that of dogs, these results are very encouraging because they show the potential of metal oxide semiconductor sensors to rapidly detect a cocaine by-product in an inexpensive way.

Graphical abstract: Cocaine by-product detection with metal oxide semiconductor sensor arrays

Supplementary files

Article information

Article type
24 Apr 2020
19 Jul 2020
First published
04 Aug 2020
This article is Open Access
Creative Commons BY license

RSC Adv., 2020,10, 28464-28477

Cocaine by-product detection with metal oxide semiconductor sensor arrays

P. Tarttelin Hernández, S. M. V. Hailes and I. P. Parkin, RSC Adv., 2020, 10, 28464 DOI: 10.1039/D0RA03687K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity