Open AccessPhoto-degradation dynamics of five neonicotinoids: Bamboo vinegar as a synergistic agent for improved functional duration
Author(s) -
Rui Liang,
Feng Tang,
Jin Wang,
Yongde Yue
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0223708
Subject(s) - acetamiprid , imidacloprid , chemistry , degradation (telecommunications) , pesticide , neonicotinoid , quenching (fluorescence) , bamboo , acetic acid , thiamethoxam , methanol , environmental chemistry , chromatography , organic chemistry , materials science , agronomy , computer science , composite material , fluorescence , biology , telecommunications , physics , quantum mechanics
The effects of photo-degradation on the utilization of pesticides in agricultural production has been investigated. Various influencing factors were compared, with results showing that the initial pesticide concentration, light source, water quality and pH possessed different effects on neonicotinoids photo-degradation. The initial concentration and pH were found to be most critical effects. The photo-degradation rate decreased by a factor of 2–4 when the initial concentration increased from 5 mg L -1 to 20 mg L -1 , particularly for acetamiprid and imidacloprid. The photo-degradation pathways and products of the five neonicotinoids were also investigated, with similar pathways found for each pesticide, except for acetamiprid. Degradation pathways mainly involved photo-oxidation processes, with products identified using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) found to be consistent with literature reported results. Bamboo vinegar exerted a photo-quenching effect on the neonicotinoids, with an improved efficiency at higher vinegar concentrations. The photo-quenching rates of thiamethoxam and dinotefuran were 381.58% and 310.62%, respectively, when a 30-fold dilution of vinegar was employed. The photo-degradation products in bamboo vinegar were identical to those observed in methanol, with acetic acid being the main factor influencing the observed quenching effects.