Periodic Reporting for period 1 - ChiPyrNMR (Better tools for combating insect borne diseases by understanding influences on the fate of common pesticides in paint formulations)
Período documentado: 2017-09-01 hasta 2019-08-31
Insecticidal paints were shown to have comparable performances with respect to other forms of effective vector control, with advantages from several points of view, such as economic, practical and environmental.iv The active ingredients of all WHO-recommended vector controls come from only four classes of insecticides: pyrethroids, organochlorines, organophosphates and carbamates.v We selected pyrethroids as our test insecticide because these compounds are the safest for public health use from both a human and an environmental point of view.vi,vii
The topic of the ChiPyrNMR project has been the analysis of chiral pyrethroids aiming at understanding, controlling and improving their stability in complex matrices like paint. NMR spectroscopy was selected as main analytical technique because it allows to investigate in-situ interaction and degradation phenomena at a molecular levelviii and it is already largely employed in paint characterization.ix
The second part of the project was instead dedicated to method development. Among the NMR pulse sequences available and used for analysis of small molecules in complex matrices, the CPMG (Carr-Purcell-Meiboom-Gill) one was chosen as a tool for “filtering” the NMR spectra of complex mixtures by exploiting the differences in relaxation between small molecules and polymers. A multivariate approach (design of experiment) was adopted in order to find a correlation between the acquisition parameters, the experimental ones and the efficiency of the filter, with particular effort in preserving the possibility to perform quantitative analysis.
A tailored analytical method for handling and analysing paint samples containing pyrethroids was then developed, guaranteeing the identification and quantification of the insecticide and the related by-products present in the matrix.
The results of these investigations were presented at different scientific conferences (MCAA 2018, EUROMAR 2018 and SMASH 2018) and two scientific papers are going to be submitted to peer review journals for publication.
iv K. L. Schiøler, M. Alifrangis, U. Kitron et al., PLoS Negl. Trop. Dis. 2016, 10, e0004518 (and references therein).
vi United States President’s Malaria Initiative. PMI guidelines for entomological monitoring and insecticide resistance management. Washington DC, 2010.
vii M. M. Sibanda, W. W. Focke, F. J. W. J. Labuschagne et al., Malar. J. 2011, 10, 307.
viii A. Martinez-Yusta, E. Goicoechea, M. D. Guillen, Nuclear Magnetic Resonance (NMR) 2014, D. K. Rao, ed.; Nova Science Publishers, Inc. Hauppauge, N. Y., 221.
ix A. Szczygiel, Nucl. Magn. Reson. 2016, 45, 142.
ActiveinsectideImpurities MethoddevelopmentforNMR analysisofpyrethroidsin complexmatrices