Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles

Rafaela Nita; Scott A Trammell; Gregory A Ellis; Martin H Moore; Carissa M Soto; Dagmar H Leary; Jake Fontana; Somayeh F Talebzadeh; D Andrew Knight

doi:10.1016/j.chemosphere.2015.10.036

Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles

Chemosphere. 2016 Feb:144:1916-9. doi: 10.1016/j.chemosphere.2015.10.036. Epub 2015 Nov 11.

Authors

Rafaela Nita¹, Scott A Trammell², Gregory A Ellis³, Martin H Moore², Carissa M Soto², Dagmar H Leary², Jake Fontana², Somayeh F Talebzadeh¹, D Andrew Knight⁴

Affiliations

¹ Chemistry Department, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901, USA.
² Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375, USA.
³ National Academy of Sciences, National Research Council, Postdoctoral Research Associate, Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375, USA.
⁴ Chemistry Department, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901, USA. Electronic address: [email protected].

PMID: 26547026
DOI: 10.1016/j.chemosphere.2015.10.036

Abstract

"Ligand-free" citrate-stabilized 10 nm gold nanoparticles (AuNPs) promote the hydrolysis of the thiophosphate ester methyl parathion (MeP) on the surface of gold as a function of pH and two temperature values. At 50 °C, the active surface gold atoms show catalytic turnover ∼4 times after 8 h and little turnover of gold surface atoms at 25 °C with only 40% of the total atoms being active. From Michaelis-Menten analysis, k(cat) increases between pH 8 and 9 and decreases above pH 9. A global analysis of the spectral changes confirmed the stoichiometric reaction at 25 °C and the catalytic reaction at 50 °C and mass spectrometry confirmed the identity of p-nitrophenolate (PNP) product. Additional decomposition pathways involving oxidation and hydrolysis independent of the formation of PNP were also seen at 50 °C for both catalyzed and un-catalyzed reactions. This work represents the first kinetic analysis of ligand-free AuNP catalyzed hydrolysis of a thiophosphate ester.

Keywords: Catalysis; Degradation; Gold nanoparticles; Methyl parathion.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Catalysis
Citric Acid / chemistry*
Environmental Pollutants / chemistry*
Gold / chemistry*
Hydrogen-Ion Concentration
Hydrolysis
Kinetics
Metal Nanoparticles / chemistry*
Methyl Parathion / chemistry*
Oxidation-Reduction
Particle Size*
Temperature

Substances

Environmental Pollutants
Citric Acid
Methyl Parathion
Gold