The adulteration of fuels is a world-wide problem as it promises easy and fast profit. However, if for instance gasoline is adulterated with cheap alcohol or hydrocarbons such as kerosene, not only motors and vehicles are damaged, but also the environment. If customers or law enforcement officers could be equipped with a simple test to detect such fraud directly on site, the possibility to uncover these illicit actions would increase. Recently, such a test that combines specifically tailored fluorescent test strips with mobile-device readout was developed at BAM. An important factor for success was the dedicated optimization of the materials properties of the paper strips. First, the cellulose was coated with a thin layer of silica, then functionalized with an indicator that changes its fluorescence color as a function of the polarity of the solution it is dipped in, and finally the remaining silica surface of the coating was passivated. The brightly fluorescent test strips allow for the reliable quantitation of fuel adulteration, while data are recorded and analyzed by a conventional smartphone. The assays are characterized by a good reproducibility and accuracy so that not only the uncovering of fraud is possible, but also the quality control of commercial fuels (e.g., gasoline E10) directly at the point of need.
Tailored fluorescent solvatochromic test strips for quantitative on-site detection of gasoline fuel adulteration
Raúl Gotor, Jérémy Bell, Knut Rurack
Journal of Materials Chemistry C, Vol. 7, Issue 8, pages 2250 - 2256
BAM, Chemical and Optical Sensing division