*3.3.3 Adulteration*

Lee et al. (2011) have developed a sensor to detect gasoline adulteration based on the solvatochromic behavior of a polydiacetylene (PDA) conjugated polymer embedded in matrix polymers of polystyrene and polyacrylic acid in the form of fibers. When exposed to pure and adulterated gasoline, they change to different colors and also change color in the presence of potential adulterants like paint thinner, methanol, and toluene (see **Figure 16**) [57].

**Figure 16.**

*Photos after the exposure of the PDA fibers in polystyrene to commercial and adulterated gasoline, thinner, methanol, and toluene on glass (a) and on silica TLC plate (b). Adapted from Lee et al. [57].*
