Abiotic Degradation of Glyphosate into Aminomethylphosphonic Acid in the Presence of Metals

J. ASCOLANI YAEL; J. D. FUHR; G. A. BOCAN; A. DAZA MILLONE; N. TOGNALLI; M. DOS SANTOS AFONSO; M. L. MARTIARENA

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 62 p. 9651 - 9656

0021-8561

Glyphosate [N-phosphono-methylglycine (PMG)] is the most used herbicide worldwide, particularly since thedevelopment of transgenic glyphosate-resistant (GR) crops. Aminomethylphosphonic acid (AMPA) is the main glyphosatemetabolite, and it may be responsible for GR crop damage upon PMG application. PMG degradation into AMPA has hithertobeen reckoned mainly as a biological process, produced by soil microorganisms (bacteria and fungi) and plants. In this work, weuse density functional calculations to identify the vibrational bands of PMG and AMPA in surface-enhanced Raman spectroscopy(SERS) and attenuated total reflectance Fourier transform infrared (ATR−FTIR) spectra experiments. SERS shows the presenceof AMPA after glyphosate is deposited from aqueous solution on different metallic surfaces. AMPA is also detected in ATR−FTIR experiments when PMG interacts with metallic ions in aqueous solution. These results reveal an abiotic degradationprocess of glyphosate into AMPA, where metals play a crucial role.