Figure 4

(a) variation in CV curves as a function of dopant (Ni and Cr) in reference to pristine SnO₂, before immobilization in 1 ppm of OP. CV curves as a function of OP concentration before and after AChE immobilization for (b) pristine SnO₂, (c) Ni-SnO₂ and (d) Cr-SnO₂ and (e) Variation in the anodic peak current with OP concentration and dopants.