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COMPARISON OF SPE CARTRIDGES FOR THE EXTRACTION OF
25 NEW PSYCHOACTIVE SUBSTANCES
Lorna A. Nisbet*, 1 M.Sc., Karen S. Scott2 Ph.D.
1 Forensic
Medicine & Science, University of Glasgow, Scotland, UK
2 Forensic Science, Arcadia University, Glenside, PA, USA
New psychoactive substances (NPS’s) have appeared on the
recreational drug market at an unprecedented rate, with new
compounds detected on a weekly basis [1]. As a result, forensic
toxicology laboratories can find themselves struggling to keep apace.
Method development is a costly and lengthy process, therefore it
makes more economical sense to adapt methods which are already in
existence to ensure the best chances of detection.
Sample clean-up is a critical step in toxicological analysis; not only does
it improve sensitivity and selectivity of results, but it also increases the
lifetime of the instruments used for detection [2].
Solid phase extraction (SPE) is one such clean up technique, however
with so many cartridge types available on the market it can be difficult
to determine which one is most suitable.
The aim of this study was to determine the most suitable SPE cartridge
to use for the extraction of a variety of NPS’s from a range of different
matrices, namely blood, urine, plasma and serum.
The drugs analysed in this research are shown below in Table 1.
Results – Synthetic Cathinones
Extraction methods for the SPE cartridge are shown below in Figures 1-3.
The highest recovery achieved for each synthetic cathinone in each matrix
and which cartridge this was achieved with is shown below in Table 3.
Table 3: Optimum cartridge recoveries for synthetic cathinones
Figure 1: Extraction method
for ZSDAU020, CSDAU133,
XRDAH206, XRDAH502 &
XRPCH50z cartridges.
Figure 2: Extraction method
for the XCEL1 cartridge
Figure 3: Extraction method
for the OASIS cartridge.
Internal standards (mephedrone-D3, methylone-D3, ethylone-D5, MDPV-D8
and 25I-NBOMe-D3) were added to the collection tubes prior to elution.
Post extraction, samples were evaporated using a stream of nitrogen,
derivatized using 50 µL of PFPA:Ethyl acetate at 70 oC for 40 minutes,
before being evaporated again, reconstituted in 100 µL of ethyl acetate
and analysed by GC-MS in full scan mode.
Results – Synthetic NBOMes
Table 1: Synthetic cathinones, NBOMes and miscellaneous compounds analysed.
NBOMe’s
Extraction Method
SYNTHETIC CATHINONES
MISCELLANEOUS
The highest recovery achieved for each NBOMe in each matrix and which
cartridge this was achieved with is shown below in Table 2.
25B-NBOMe
MESCALINE-NBOMe
BENZEDRONE
2-DPMP
25C-NBOMe
25N-NBOMe
BUTYLONE
3-MeO-PCE
25D-NBOMe
25P-NBOMe
ETHYLONE
5-APB
DRUG
BLOOD
URINE
PLASMA
SERUM
25E-NBOMe
25T2-NBOMe
FLEPHEDRONE
6-APB
25B-NBOMe
CSDAU (86%)
CSDAU (85%)
ZSDAU (117%)
XCEL 1 (71%)
25H-NBOMe
25T4-NBOMe
MDPV
METHIOPROPAMINE
25C-NBOMe
CSDAU (83%)
CSDAU (85%)
ZSDAU (76%)
ZSDAU (82%)
25I-NBOMe
25T7-NBOMe
MEPHEDRONE
METHOXETAMINE
25D-NBOMe
CSDAU (102%)
XRDAH 206 (109%)
ZSDAU (117%)
ZSDAU (111%)
25ENBOMe
CSDAU (110%)
CSDAU (110%)
ZSDAU (111%)
ZSDAU (108%)
25H-NBOMe
CSDAU (99%)
CSDAU (139%)
XCEL 1 (51%)
ZSDAU (81%)
25I-NBOMe
CSDAU (90%)
ZSDAU (90%)
XCEL 1 (47%)
ZSDAU (118%)
MescalineNBOMe
XCEL 1 (49%)
XCEL 1 (50%)
ZSDAU (41%)
XRDAH 502 (90%)
25N-NBOMe
ZSDAU (81%)
ZSDAU (98%)
ZSDAU (105%)
ZSDAU (118%)
25P-NBOMe
XRDAH 206 (69%)
ZSDAU (76%)
ZSDAU (63%)
ZSDAU (62%)
25T2-NBOMe
XRDAH 206 (111%)
XRDAH 206 (108%)
ZSDAU (66%)
XCEL 1 (81%)
25T4-NBOMe
CSDAU (105%)
CSDAU (105%)
ZSDAU (64%)
XCEL 1 (70%)
NAPHYRONE
Sample Preparation
Blank methanol, urine, blood, plasma and serum samples (1 mL) were
spiked with 200µL of 10 µg/mL solutions of the selected NPS’s. To each
sample, 1mL of 0.1M phosphate buffer (pH6) was added before
centrifugation for 10 minutes at 4000rpm. Samples were then
extracted using a range of solid phase extraction cartridge; UCT’s
XCEL1, ZSDAU020, CSDAU133, XRDAH206, XRDAH502, XRPCH50z as
well as Waters Oasis.
DRUG
BLOOD
URINE
PLASMA
SERUM
BENZEDRONE
XRDAH 206 (47%)
OASIS (124%)
BUTYLONE
XCEL 1 (80%)
OASIS (119%)
XCEL 1 (101%)
XCEL 1 (87%)
ETHYLONE
ZSDAU (115%)
OASIS (87%)
XCEL 1 (79%)
XCEL 1 (79%)
FLEPHEDRONE
CSDAU (65%)
CSDAU (38%)
CSDAU (67%)
CSDAU (63%)
MDPV
CSDAU (56%)
XCEL 1 (105%)
XCEL 1 (109%)
XCEL 1 (100%)
MEPHEDRONE
CSDAU (112%)
CSDAU (101%)
CSDAU (88%)
CSDAU (126%)
NAPHYRONE
XRDAH 502 (40%)
XCEL 1 (113%)
XRDAH 206 (48%) XRDAH 502 (47%)
XRDAH 502 (42%) XRDAH 502 (47%)
Results – Miscellaneous Drugs
The highest recovery achieved for each miscellaneous drug in each matrix
and which cartridge this was achieved with is shown below in Table 4.
Table 4: Optimum cartridge recoveries for miscellaneous drugs
DRUG
BLOOD
URINE
PLASMA
SERUM
2-DPMP
CSDAU (88%)
CSDAU (115%)
CSDAU (89%)
CSDAU (97%)
3-MeO-PCE
XRDAH 206 (45%)
XCEL 1 (96%)
XRDAH 206 (60%)
ZSDAU (50%)
5-APB
CSDAU (49%)
XCEL 1 (95%)
CSDAU (63%)
CSDAU (71%)
6-APB
ZSDAU (27%)
XCEL 1 (94%)
ZSDAU (45%)
CSDAU (51%)
METHIOPROPAMINE
OASIS (52%)
XCEL 1 (80%)
XCEL 1 (27%)
ZSDAU (43%)
METHOXETAMINE
XRDAH 206 (56%)
XCEL 1 (70%)
XRDAH 206 (66%)
ZSDAU (58%)
Table 2: Optimum cartridge recoveries for NBOMes
25T7-NBOMe
XCEL 1 (106%)
XCEL 1 (106%)
ZSDAU (115%)
ZSDAU (107%)
Conclusion
This study has shown that when analysing urine and blood samples the
smaller bed size of the CSDAU cartridges is preferable and when
analysing plasma and serum samples ZSDAU cartridges should be used.
XRPCH50z cartridges, using the method tested, are not recommended
for sample clean-up of NPS compounds.
Acknowledgements
The authors would like to thank United Chemical Technologies and Waters for the supply
of SPE cartridges and the Center for Forensic Science Research and Education for
supporting this research.
References
1. European Monitoring Centre for Drugs and Drug Addiction ( EMCDDA). (2014)European Drug Report 2014: Trends and developments [Online]. Available
from:http://www.thehealthwell.info/node/769814 [Accessed: 6th October 2014].
2. Moffat, A C, Osselton, M D and Widdop, B, [ed.]. Clarke's Analysis of Drugs and Poisons. 3rd. s.l. : Pharmaceutical Press, 2004. pp. 1072-1073. Vol. 2.