Fig. 9

(a) Linear plot of Benesi-Hildebrand method absorbance at 361 nm, (b) MPTP detection limit for Fe3+ at 50µM absorbance at 361 nm, (c) pH impact on MPTP and MPTP-Fe3+ absorbance at 361 nm, and (d) Visual response of MPTP-loaded test strips upon exposure to increasing concentrations of Fe3+ (50µM, 100µM, 200µM).