Natural peptide products isolated from various organisms often contain N-methylated backbones. Such a modification of backbone of the peptide changes its conformational rigidity. This modification improves the biological properties of the peptide, such as improved target affinity, proteolytic stability or membrane permeability. Therefore synthesis of N-methylated peptide libraries is valuable in screening for drug-like peptides suitable for therapeutic uses. Protein synthesis using recombinant elements (PURE) and Flexizyme were used in order to reassign specific codons to N-methyl amino acids. mRNA-dependent translation system enable us to make our desired peptides with N-methyl amino acids. This technology is a convenient tool for the construction of N-methyl peptide libraries. Using Flexizyme in order to make library of N-methyl peptides requires significant amount of tRNA. Therefore developing a simple and rapid method for purification of specific tRNA from fully modified E. coli total tRNA would be advantageous Here we reported a new technique in purification of individual tRNAs using fluorous affinity tag. From total tRNA, desired tRNA could be charged with related amino acid and tagged with fluorous molecule through reductive amination.