Highly polar organic substances may be able to
penetrate natural and artificial barriers and are thus
mobile in the water cycle. If these mobile organic
contaminants (MOC) are persistent (PMOC)
against microbiological and chemical degradation,
their removal during waste water treatment and
drinking water purification[1] may prove difficult. If
these substances are present in high concentrations,
toxic or undergo toxication[2], problems for the aquatic
environment and human health may arise.
As a consequence of the lack of established
analytical methods for MOC, only limited
information about the occurrence fate and
distribution of these substances is available. In the
PROMOTE project, we strive to close this gap in
knowledge.
In this work, a newly developed SPE[3] method that
allows enrichment of PMOC from aqueous samples is
presented and deployed in combination with a
suitable HILIC/HRMS method to perform a non-target
screening for potential PMOC in environmental water
samples, including polluted well and ground water,
tap water and milliQ water as blank. Preliminary
results of the non-target screening are shown.
Daniel Zahn, Tobias Frömel, Thomas P. KnepperCorresponding e-mail address: [email protected]
University of Applied Sciences Fresenius, Institute for Analytical Research (IFAR), Idstein, Germany
Non-target screening of highly polar organic micropolutants in environmental
water samples
Introduction
100 mLpH 5.5
H2O
WCXGCB
MeOH
ACN/H2OWAX
HILIC/HRMS
+ 6556- 3122∑ 9678
N2
well water
tap water
ground water
t0
tap water
ground water
well water
milliQ water
m/z 215.0384rel. height 100%
m/z 216.0416rel. height 10.1% m/z 217.0340
rel. height 4.3%
Elemental composition:C9H11O4S
-
∆ = 0.4 ppm
C9H11O4S- appears to have a sufficient persistency
and mobility in the water cycle to reach drinking
water, and is thus classified as PMOC.
Structure and origin of C9H11O4S are still under
investigation.
XIC 215.0384width 5ppm
milliQ water
MS
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www.ufz.de/promote or use this QR code
XICswidth 5ppmall ground water
C8H7SO5-
∆ = -1.3 ppm
C12H15SO5-
∆ = -0.4 ppm
C13H17SO5-
∆ = -1.7 ppm
C10H11SO5-
∆ = -0.1 ppm
C9H9SO5-
∆ = 0.1 ppm
C11H13SO5-
∆ = 1.1 ppm
MS² C11H13SO5-
Conclusion and outlook
XIC 148.9526width 5ppm
milliQ water
tap water
well water
ground water
MS
m/z 148.9527rel. height 100%
m/z 149.9558rel. height 0.8%
m/z 150.9482rel. height 4.5%
Elemental composition:CF3SO3
-
∆ = 1.1 ppm
The unequivocal elemental composition for the ion
m/z 148.9526 is CF3SO3-. Only two chemically sound
structures exist for this elemental composition:
References:
[1] T.P. Knepper et al. Waste Manage. (Oxford) 1999, 19,
77-99.
[2] Schmidt, C. K.; Brauch, H.-J. Environmental Science &
Technology 2008, 42, 6340.
[3] Zahn, D.; Frömel, T.; Knepper, T. P. work in progress
Acknowledgement:
We thank the BMBF and JPI water for funding the
PROMOTE (Protecting Water Resources from Mobile
Trace Chemicals) project (FKZ: 02WU1347B).
F
F
F
S
O
O
O-
FF
F
SO
O
O-
Trifluoromethanesulfonate Trifluoromethyl sulfite
Of the two proposed structures for m/z 148.9526
Trifluoromethanesulfonate, the anion of triflic acid, is
more likely to occur in environmental water samples.
Triflic acid has a high production volume (> 100 t/a)
and is applied in various processes including
vulcanization and polymerization. A confirmation of
the proposed structure is still pending.
MS² C12H15SO5-
Indicates R-SO3H
Odd electron fragment.
Indicates increased radical
stability. Fragment is
independent of chain lengths.
Cleavage of CO2
indicates R-COOH
A supposed series of homologues was observed
during the non-target screening. The MS2 spectra
of the most abundant homologues (assuming a
similar ESI response) were compared to facilitate
structural elucidation. In addition, fractions were
collected, evaporated to dryness, reconstituted in
D2O/ACN 1:1 (v:v) and measured with HRMS by
direct infusion.
For both homologues a cleavage of CO2 as well as
an SO3●- fragment were observed, indicating the
presence of a carboxylic acid and a sulfonic acid
group respectively.
The fragment C7H6O3S●- is identical for both
homologues and violates the even electron rule,
thus indicating a position of increased radical
stability in the molecule. A benzylic position appears
to be most likely but other alternatives cannot be
ruled out by the available spectrometric information.
The mass shift of 1 Da for the deprotonated
molecule after H/D exchange is in compliance with
the proposed structure. Structural elucidation of
these substances is still ongoing.
C7H6S
O
O
OH
O
OH
(CH2)n
Area: 4.5*105
Area: 1.2*107
Area: 7.5*107
Area: 3.4*105
Area: 6.3*106
Area: 1.3*108
Area: 1.8*106
Area: 9.8*106
Area: 5.0*107
Area: 2.6*108
Area: 1.3*108
Area: 6.0*105
The preliminary screening results are a strong
indicator that PMOC may impact drinking water.
Identification of the detected substances, however is
a laborious task and prioritization is required to select
the most promising and important candidates for
structural elucidation.
A more comprehensive screening campaign with a
higher number of samples and a spatial spread over
several European countries is in preparation.
