Synthesis of a heptapeptide and its application in the detection of mercury(II) ion

A new heptapeptide, Cys-Pro-Gly-Cys-Pro-Gly-Cys-CONH 2 (P7), was prepared via Fmoc solid-phase peptide synthesis, purified by high performance liquid chromatography(HPLC) and characterized by mass spectro-metry(MS). The interactions of P7 with metal ions were also investigated by spectroscopy and the results show that P7 has highly selective binding affinity to Hg(II). Based on this specific character, a simple, rapid and sensitive detection method for Hg(II) was developed. When the mixture solution of P7 and Hg(II) was added to colloidal gold nanoparticles(GNP), the color of GNP changed from red to blue. On the contrary, the color of GNP remained unchanged when the mixture solutions of P7 and other metal ions were added.