I'm going to do immunofluorescence staining to check phage entry into cells. The protocol says cells have to be treated with 50mM ammonium chloride to quench free aldehyde groups from fixation before cell permeabilization. However, our lab do not have NH4Cl, I'm wondering if any chemical can be used to replace NH4Cl? Thank you!
Actually, I have never found this quenching step necessary in about 30 years of my experience in different tissues and antibodies. The primary factor for the "background" is the specificity of the primary antibody. If the primary antibody is good all your problems will disappear.
Besides the NH4Cl has a horrible urine like smell!
With best regards
Make up your fix and buffer wash with 0.15 M glycine. It is a rather traditional and simple way to quench background fluorescence.
Emilia - Since you apparently need a diluted solution (50 mM) of ammonium chloride I suggest the you prepare small amount of the salt directly be neutralizing hydrochloric acid with an aqueous solution of ammonia according to the attached equation. Then you can use the solution right away if you calculated the ammonium chloride content. Alternatively you can evaporate the solution to dryness to obtain solid NH4Cl. This can then be redissolved in water to give the required concentration. This is perhaps safer than trying an alternative reagent.
Just Tris-buffer may works fine, as like any source of ammonium radicals
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