A method for making a composite polyamide membrane comprising a porous support and a polyamide layer, including the steps of: i) applying a polar solution comprising a polyfunctional amine monomer and a non-polar solution comprising a polyfunctional acyl halide monomer to a surface of a porous support and interfacially polymerizing the monomers to form a polyamide layer; and ii) exposing the thin film polyamide layer to nitrous acid; wherein the method is characterized by at least one of: conducting the interfacial polymerization of step i) in the presence of a subject amine compound, or applying a subject amine compound to the interfacially polymerized polyamide layer prior to step ii), wherein the subject amine compound is different from the polyfunctional acyl halide and polyfunctional amine monomers.