Synthesis and analysis of zinc-methionine, zinc-tryptophan, copper-lysine, and copper-isoleucine complexes using atomic absorption spectrophotometry

Objective: This study aimed to synthesize an organic form of Zn and Cu to then produce metal complexes with amino acids, as well as to analyze the free and bound metal content of the complexes. Methods: In this study, the synthesis methods for zinc-methionine (Zn(Met)₂), zinc-tryptophan (ZnTrp), copper-lysine (Cu(Lys)₂), and copperisoleucine (Cu(Ile)₂) complexes were based on previous studies. Sample verification was conducted using Fourier transform infrared spectroscopy, which can determine the stretched spectra produced by the complexes. In addition, atomic absorption spectrophotometry was used to analyze the metal content of the complexes. Results: The yields gained from the synthesis of Zn(Met)₂, ZnTrp, Cu(Lys)₂, and Cu(Ile)₂ complexes were 95.99%, 94.18%, 91.89%, and 95.73%, respectively, with a maximum metal content of 199.51, 246.98, 176.99, and 189.75 mg/g, respectively. Conclusion: The mineral concentration of each complex differed, depending on the type of mineral and ligand.