Figure 4From: Reaction of 2,6-dichloroquinone-4-chloroimide (Gibbs reagent) with permethrin – an optical sensor for rapid detection of permethrin in treated woodEffects of the nafion/sol–gel silicate ratio towards chemical sensor response. Permethrin concentration: 50.0 μM; concentration of Gibbs reagent: 1.0 M; pH: 9.0.Back to article page