Neonicotinoid pesticides are often viewed as less toxic than other classes of pesticides, and so have seen widespread adoption for the insecticidal treatment of food crops. Given their solubility, they have even been added to irrigation water to facilitate easy and targeted application. Nevertheless, these pesticides also persist in the environment and have been implicated in the collapse of honey bee colonies and declines in insect-eating bird populations. While there is evidence for these associations, more extensive environmental monitoring campaigns are needed to better assess their occurrence and fate, particularly at locations farther removed from application sites. Currently, the neonicotinoids are routinely analyzed by solid phase extraction with high performance liquid chromatography-mass spectrometry (SPE-HPLC-MS). Though analytical advances (e.g. ultra-HPLC) have increased throughput for analyses, SPE is usually needed to concentrate the target compounds and minimize matrix interferences. SPE can be time-consuming and use substantial amounts of solvent. To increase the throughput of analysis in water and liquid matrices, we have fabricated thin-film molecularly imprinted polymers (MIPs) for selective analyte uptake of analytes in situ or in a controlled environment. In the film format, the analytes bound in the MIPs can be analyzed directly by desorption electrospray ionization (DESI)-MS. MIPs rely on a simple mode of molecular recognition that occurs in cavities formed through polymerization of functional monomer(s) and crosslinker(s) in the presence of the template (usually the target analyte). For an optimal MIP system, several aspects of polymer fabrication and composition must be considered, including: choice of template and functional monomer, ratio of polymer components, nature and amount of the porogen, etc. The sensitivity of DESI-MS, like electrospray ionization, also depends on a careful selection of conditions, but with geometric parameters also playing key roles. Results of the optimization efforts for the neonicotinoid MIPs, and data from method development studies with DESI-MS will be presented. Suitability for the analysis of neonicotinoids in water will also be discussed.

Molecularly imprinted polymers with desorption electrospray ionization mass spectrometry for high throughput analysis of neonicotinoids pesticides in water and food

251st National Meeting (2016)

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