There is an increasing need for developing a strategy
to analyze
the penetration of pesticides in cultures during postharvest control
with minimal or no sample preparation. This study explores the combined
use of laser ablation electrospray ionization mass spectrometry imaging
(LAESI imaging) and tissue spray ionization mass spectrometry (TSI-MS)
to investigate the penetration of thiabendazole (TBZ) in fruits, simulating
a postharvest procedure. Slices of guava and apple were prepared,
and an infrared laser beam was used, resulting in the ablation of
TBZ directly ionized by electrospray and analyzed by mass spectrometry.
The experiments were conducted for 5 days of fruit storage after TBZ
administration to simulate a postharvest treatment. During postharvest
treatment, TBZ is applied directly to the fruit peel after harvesting.
Consequently, TBZ residues may remain on the peel if the consumer
does not wash the fruit properly before its consumption. To evaluate
the effectiveness of household washing procedures, TSI-MS was employed
as a rapid and straightforward technique to monitor the remaining
amount of TBZ in guava and apple peels following fruit washing. This
study highlights the advantages of LAESI imaging for evaluating TBZ
penetration in fruits. Moreover, the powerful capabilities of TSI-MS
are demonstrated in monitoring and estimating TBZ residues after pesticide
application, enabling the comprehensive unveiling of pesticide contaminants
in fruits.