Synthesis of heterotelechelic poly(ethylene glycol)s and their characterization by MALDI-TOF-MS

Departamento de Ingenieri´a Qui´mica, Universidad Polite´cnica de Catalun˜a,E. T. S. de Ingenieros Industriales, Diagonal 647, 08028 Barcelona, Spain(Received: October 2, 1998; revised: November 26, 1998)SUMMARY: Two heterotelechelic poly(ethylene glycol)s were synthezised by end group modification of a-hydro-x-hydroxy-poly(oxyethylene) (PEG). The first reaction route starts from heterobifunctionala-hydro-x-octadecanoyloxy-poly(oxyethylene) (400) and comprises the synthesis ofa-hydro-x-carboxymethoxy-poly(oxyethylene). The second pathway starts from homotelechelic PEG(400) and leads to a-(2-propenyl)-x-carboxymethylthio-poly(oxyethylene). Purification of the desired products was accomplished by means ofion exchange chromatography on DEAE Sephadex. PEG derivatives were characterized by means of NMR,IR, HPLC and GPC. MALDI-TOF-MS recorded in the reflectron mode served as a fine method that providesinformation on chemical composition as well as molecular weight.