Redox-Reaction Based Spectrophotometric Assay of Isoniazid in Pharmaceuticals

Figure 4

(a) Effect of volume of FeCl₃ for method B (1.5 μg mL⁻¹ INH). (b) Effect of volume of ferricyanide for method B (1.5 μg mL⁻¹ INH). (c) Reaction time and stability of colored species for method B (1.5 μg mL⁻¹ INH).

(a)

(b)

(c)