AccuTOF TM with DART TM
Rapid Detection of Fungicide in Orange Peel
Thiabendazole is an anthelmintic and a highly persistent
systematic benzimidazole fungicide that is widely used
for controlling spoilage in citrus fruit. It is considered a
General Use Pesticide (GUP) in EPA Toxicity Class III –
Slight Toxicity.
A small piece of orange peel (a few square
millimeters in size) from a Florida orange was placed in
the DART sampling region. Compounds present in the
peel were detected within seconds. Among these were
the familiar orange-oil flavor components such as
limonene and sinensal as well as polymethoxylated
flavones that are attributed with antioxidant and
cholesterol-reducing properties.
Polymethoxyflavones
n=6
Limonene
n=5
n=4
n=7
Sinensal
100
150
200
250
300
350
400
450
m/z
An enlarged view of the region near m/z 202 is shown
below. The large peak at m/z 205.1949 has the
elemental composition C15H24, assigned as the [M+H]+
for farnesene. Residual thiabendazole was detected as
[M+H]+ at m/z 202.0444, which differs by only 0.0005
from the theoretical m/z of 202.0439.
N
Thiabendazole
MH+
N
N
H
S
Thiabendazole
190
195
200 205
m/z
210
215
C10H7N3S
Measured: 202.0444 Da
Calculated: 202.0439 Da
Difference: 0.0005 Da
Conclusion: DART was used for the rapid detection of trace pesticides on fruit.
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