Biosensor Construction. A mixture of enzyme, substrate, chromophore, and stabilizer solution was prepared for the indicated final concentrations in each experiment. For preparing biosensor strips, Munktell filter paper discs were prepared in 1 × 1 cm pieces and autoclaved at 120∘C for 25 minutes prior to use (Figure 1(a)). Filter papers were then fixed via two-sided plaster on plastic supports (Figure 1(b)). A mixture of AChE and DTNB solution of 15