Neßler's<unk>  is a<unk>  named after Julius Neßler and is used to detect small amounts of ammonia. It is a 0.09 mol/L solution of potassium tetraiodomercurate(II) (K2[HgI4]) in 2.5 mol/L potassium hydroxide. A yellow coloration indicates the presence of ammonia: at higher concentrations, a brown precipitate may form. The sensitivity as a spot test is about 0.3 μg NH3 in 2 μL.
Nessler's reagent
Trypan Blue
Trifoliate orange
Polynoxylin
Hemocyanin
Silver stain
Phenol red
AT-10 resin