A Sensitive and Simple Method for Trace Analysis of Pesticide Residues in Plant Guttation Fluids

Analysis of pesticide residues in guttation fluids remains challenging due to the small quantity of fluids. A multimode inlet technique was utilized to increase the detectability of 12 pesticide residues in guttation fluids on Epipremnum aureum leaves collected with a pipet. A 500-μL sample of guttation fluid was vortex-extracted with an equal volume of dichloromethane. The extracts were dried over sodium sulfate anhydrous, followed by gas chromatography-tandem mass spectrometry analysis. Multiple injection mode and solvent vent mode were combined for a large-volume injection (e.g., 10 μL). The method was validated for the analysis of 12 systemic pesticides in guttation fluids for detection selectivity (no interferences), method limit of quantification (1-5 μg/L), linearity (>0.993), accuracy (70.7%-116%), precision (2.0%-17.0%), and matrix effect (-3.9%-304%). Kinetics of pesticide residues in the guttation fluids over time were monitored. This method is hopefully useful for the analysis of pesticide residues in guttation fluids.