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Productivity and Utilization of DART
Chemical terrorism involving contamination of drinking
water and/or food targeting a non-specific group creates
the need to develop appropriate countermeasures. To
confirm the contaminating compound using the
conventional microanalysis method on five samples, for
example, would require approximately 0.5 to 1 L of
sample and take 2.5 to 3 hours for filtration and liquid-
liquid extraction (LLE) or solid-phase extraction (SPE)
and 1.2 hours for instrumental analysis. On the other
hand, the method described here would require only 5 to
10 µL of sample and only 0.5 minutes of analysis time.
Thus, DART provides speed in comparison to the
conventional method.
Although it was not reviewed in this study, quantitation
review cases on the application of the DART-high-
resolution mass spectrometry (HRMS) method have been
reported.
10,11
If the injection method was to be automated,
this method could be especially useful in the fields of
water, food, and soil quality control, as it could be used to
identify the contaminating compound and confirm its
concentration at the same time. Also, desorption
ionization methods including DART have a simple
ionization mechanism. This reduces the time necessary for
optimization and the cost related to the solvent, column,
and condition establishment time, etc., necessary when
using HPLC. As such, this method is expected to have
diverse applicability in environmental analysis including
quantitation.
Conclusion
In this study, DART, a direct analysis technique that has
been introduced for rapid response to water contamination
accidents, was combined with Exactive Orbitrap HRAM
MS. Its performance as a microanalysis method for trace
amounts of contaminants in water was reviewed. Based
on the results, the following conclusions were reached:
• An analysis of agricultural pesticides using
DART-Orbitrap MS showed that it was possible to
produce accurate identification with a mass accuracy
within 1 ppm in a very short period of time without any
sample pre-treatment.
• This method demonstrated a detection limit of 1 ng/mL
in a sensitivity test using acetochlor, without prior
extraction or sample concentration, showing the
possibility of using it as a method to detect trace amounts
of target compounds.
• The DART method was observed to significantly reduce
the analysis time and labor necessary. The speed of the
method could also be an advantage if an urgent analysis
is needed in the event of an accident that could
potentially have a negative impact on the environment.
It is also a simple, environmentally-conscious analysis
technique, as it does not require large amounts of
solvent.