${\mathrm{PhNH}}_2$ and $\mathrm{PhNHMe}$ can be differentiated by :

$1^{\mathrm{o}}$ and $2^{\mathrm{o}}$ Both the isocyanide test and diazotization can be used to identify amines. ${\mathrm{PhNH}}_2$ is $1^{\mathrm{o}}$ An offensive odour is produced by the amine and positive isocyanide test while $\mathrm{PhNHMe}$ never does.