Development of analytical protocol for the investigation of transformation products of pre-harvest fungicides in fruits using LC-MS/MS methods

ABSTRACT

Chemical protection of plants is critical to permit all-year-long availability of plant products. These chemical agents are transformed both biotically and abiotically after spraying. Our purpose was to develop a workflow which is suitable to investigate those transformation products from plant matrices. Two field trials were set up in two years in two different plant matrices (apples, cherries) to develop a workflow to map the transformation products (TP) of three selected pre-harvest fungicides (boscalid, fluopyram, pyraclostrobin) in the fruits. Modified QuEChERS extraction method was applied for the extraction of TPs from the fruit matrices. We used liquid chromatograph-mass spectrometers to identify and confirm the transformation products of fungicides. LC-QTOF-MS method was suitable to map the key fragmentation routes of parent fungicides. Based on fragmentation pathways, MRM (multiple-reaction monitoring) transitions of fungicide-metabolites mentioned in the literature were predicted. HPLC-QTRAP-MS in target mode was successfully applied to monitor trace level of metabolites and in some cases their isomers. For confirmation of the identified metabolites, LC-QTOF-MS was used. Five earlier-documented as well as one novel transformation product (deschloro-FLP) were found in the investigated fruit samples, the latter has not been reported in plant matrices so far. Area-normalisation method was used to follow the relative concentration of the transformation products in the fruits as a function of time.

KEYWORDS:

• Metabolomical research
• pesticide transformation products
• mass spectrometry

Acknowledgments

The authors would like to acknowledge the financial support of the European Union and the co-financing provided by the European Social Fund (grant agreement no. EFOP3.6.3-VEKOP-16-2017-00005) and the ÚNKP-18-1-I-SZIE-4 New National Excellence Program of the Ministry of Human Capacities.

Declaration of interest

The authors declare that they have no conflict of interest.

Supplementary material

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