C) Sulfanilamide solution (2%): 2 g Sulfanilamide (p.a., Merck) was dissolved in 100 mL 10% (v/v) HCl.
D) NOx reagent (Griess + reduction reagent): 5 parts A + 1 part B + 1 part C.
E) Nitrite reagent (Griess reagent): 1 part B + 1 part C.
F) Sulfamic acid (60 mM): 583 mg Sulfamic acid (p.a., Merck) was
dissolved in 100 mL ultrapure water.