Science and Justice xxx (2014) xxx–xxx

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Isotopic profiling of seized benzylpiperazine andtrifluoromethylphenylpiperazine tablets using δ13Cand δ15N stable isotopes

Nicola M. Beckett a,b,⁎, Sarah L. Cresswell a,2, Darren I. Grice b,c,1,3, James F. Carter d,4

a School of Natural Sciences, Griffith University, Nathan campus, Queensland, Australiab Institute for Glycomics, Griffith University, Gold Coast campus, Queensland, Australiac School of Medical Science, Griffith University, Gold Coast campus, Queensland, Australiad Queensland Health Forensic and Scientific Services, Coopers Plains, Queensland, Australia

⁎ Corresponding author at: Institute for Glycomics, GrifGold Coast campus, Queensland, Australia. Tel.: +61 7 55

E-mail addresses: n.beckett@griffithuni.edu.au (N.M. Bs.cresswell@griffith.edu.au (S.L. Cresswell), d.grice@griffitJim_Carter@health.qld.gov.au (J.F. Carter).

URL:E-mail addresses:E-mail address: https://www.gri(D.I. Grice).

1 Institute for Glycomics, Griffith University, Gold CoAustralia. Tel.: +61 7 55527027.

2 Forensic Science Research and Innovation Centre, SchUniversity, Nathan campus, Queensland 4111, Australia. T

3 School of Medical Science, Griffith University, Gold CAustralia. Tel.: +61 7 55527027.

4 Forensic and Scientific Services, Queensland Health, CAustralia. Tel.: +61 7 32749228.

http://dx.doi.org/10.1016/j.scijus.2014.08.0031355-0306/© 2014 Forensic Science Society. Published by

Please cite this article as: N.M. Beckett, et al.,and δ15N stable isotopes, Sci. Justice (2014),

a b s t r a c t

a r t i c l e i n f o

Article history:Received 14 January 2014Received in revised form 29 May 2014Accepted 26 August 2014Available online xxxx

Keywords:Designer drugsIsotopic profilingIRMSBenzylpiperazineTrifluoromethylphenylpiperazineSeized tablets

This paper demonstrates the use of isotopic analysis of 23 benzylpiperazine (BZP) and trifluoromethylphenylpi-perazine (TFMPP) containing tablets seized on two independent occasions by the Northern Territory (NT) Police,Australia. Isolation (High Performance Liquid Chromatography (HPLC)) of BZP and TFMPP followed by IsotopeRatio Mass Spectrometry (IRMS) (carbon and nitrogen stable isotopes) analysis was performed. Results are pre-sented for δ13C and δ15N values of the respective piperazine analogues. The isotopic data and statistical analysissuggest a common source ofmanufacture for the BZP samples but suggest different sources for the TFMPP isolat-ed from the corresponding BZP containing tablets investigated. The use of IRMS in this case study demonstratedthe ability to obtain information regarding the BZP/TFMPP sources unattainable via conventional chemicalanalysis.

© 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

1. Introduction

A goal within forensic drug investigations is to establish intelligenceregarding possible links, or discriminating samples, between drug cases.Traditionally, intelligence is established through chemical profiling,such as impurity profiling via combined Gas Chromatography–MassSpectrometry (GCMS) [1]. Traditional chemical profiling of high profiledrugs such as 3,4-methylenedioxymethamphetamine (MDMA) andmethamphetamine (MA) has demonstrated the ability to provide infor-mation on the synthetic route employed in addition to identifying the

fith University, Parklands Drive,527027.eckett),h.edu.au (D.I. Grice),

ffith.edu.au/glycomics

ast campus, Queensland 4222,

ool of Natural Sciences,, Griffithel.: +61 7 3735 7824.oast campus, Queensland 4222,

oopers Plain, Queensland 4108,

Elsevier Ireland Ltd. All rights reserv

Isotopic profiling of seized benhttp://dx.doi.org/10.1016/j.sc

precursor chemicals used in a drug's preparation by identifyingtraces of precursors and by-products [2–9]. Other profiling methodsare available and one that has gained interest as a tool for discrimi-nating between different precursor sources/preparative methods,[10–16] and linking drug seizures [17–20] for natural, syntheticand semi-synthetic drugs is isotopic profiling via Isotope RatioMass Spectrometry (IRMS).

IRMS has emerged as a powerful technique for the profiling ofnumerous sample types relevant to forensic investigation, in partic-ular illicit drugs. Profiling of seized and authentic drug samples forinvestigating sources, linkage (between sample groups, precursor–product relationships, etc.) or discrimination purposes has beendemonstrated for numerous synthetic substances including MDMA[21–23], MA [10–13,15,19,24,25] and more recently the designerdrug mephedrone [16].

It has been suggested that each batch of synthetic drugs has a uniqueisotopic profile which forms the basis for discriminating/linking via isoto-pic analysis. Carter et al. [26], reported that throughmultivariable isotopicanalysis the clustering ofMDMA sampleswas identified, reflecting specif-ic production batches. The isotopic composition of phenylethylamine an-alogues and other synthetic compounds including the designer drugsbenzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP)reflects both the characteristics of the startingmaterials used and the syn-thetic processes employed [18,27]. By determining the abundances of 13C

ed.

zylpiperazine and trifluoromethylphenylpiperazine tablets using δ13Cijus.2014.08.003

2 N.M. Beckett et al. / Science and Justice xxx (2014) xxx–xxx

and 15N isotopes within these drug molecules information regarding thesynthetic origins of these substances can be elucidated. This isotopic com-position relates to the isotopic composition of the precursors used to syn-thesize the drug products and depends on their origin and fractionationprocesses these compounds undergo [11,28]. Once a drug compound isformed, itwill retain its natural stable isotope abundance until it degrades[29]. Therefore, differences in the stable isotope abundances in the pre-cursors, originating from different sources, will allow discrimination be-tween the different products via IRMS analysis. Iwata et al. [19] hasused 15N isotope analysis in conjunction with impurity profiling to dis-criminate between MA crystals from three individual packages seized si-multaneously. The 15N composition discriminated two major groups andfurther subgroups of the MA crystals. Iwata et al. suggested multiple pre-cursor sources were used to synthesize the MA, which was subsequentlymixed and dispersed between the packages.

BZP and TFMPP (Fig. 1), belong to a class of psychoactive designerdrugs currently available on the illicit market, which are easily syn-thesized from the parent drug piperazine [30]. The popularity ofthese ‘party pills’ or ‘herbal pills’ grew exponentially in countriessuch as New Zealand, before becoming controlled in 2008 [31]. Thepopularity of piperazine analogues in some areas reflects their useas mimics to or substitutes for already scheduled illegal drugs suchas MDMA [32].

This paper describes the use of IRMS for the analysis of 23 seizedtablets containing both BZP and TFMPP piperazine analogues fromtwo separate cases provided by the Northern Territories (NT) Police,Australia. The nature of the piperazine analogues was established viaGCMS (conducted by the police) prior to IRMS analysis. No informa-tion regarding source of these compounds could be obtained fromGCMS analysis and, hence isotope analysis was employed. Thestudy used High Performance Liquid Chromatography (HPLC) to iso-late BZP and TFMPP from each tablet. Subsamples of the isolatedcompounds were characterised via 1H and 13C Nuclear Magnetic Res-onance (NMR), followed by IRMS (carbon and nitrogen isotopes)analysis of the remaining respective drugs. The isotopic data setswere compared to establish if any linkage/grouping was evidentwhichmight suggest a common source of manufacture and ultimate-ly providing insight into the designer drug network within the NTregion.

2. Materials and methods

2.1. Materials

Piperazine-containing tablets (tablet mass range of 260–300 mg)were individually homogenized (mortar and pestle) and dissolved inde-ionized water (DI) (1 mL) before being frozen with liquid nitrogenand freeze-dried overnight.

2.2. HPLC isolation

Chromatographic separations were performed using an Agilent1100 LC series HPLC with UV detection at 208 nm (Agilent Technol-ogies, Forest Hill, Australia). Data were acquired using ChemstationSoftware (Agilent Technologies). All separations were accomplishedusing a Synergi Hydro-RP Phenomenex column of dimension

Fig. 1. Structures of psychoactive designe

Please cite this article as: N.M. Beckett, et al., Isotopic profiling of seized benand δ15N stable isotopes, Sci. Justice (2014), http://dx.doi.org/10.1016/j.sc

250 mm × 10 mm (Phenomenex, Sydney, Australia) with reversed-phase mode and a mobile phase gradient. The components of themobile phase were: a mixture of water with addition of 0.05% aque-ous trifluoroacetic acid (TFA) (A) and 100% acetonitrile (B). The flowrate of the mobile phase was 3 mL min−1. The total analysis timewas 17.6 min. The elution proceeded with the following gradient:0–6.8 min 86% A/14% B, 6.8–12 min 65% A/35% B, 12–17.6 min 86%A/14% B. Cutting times of target isolate collections were BZP; 4.95–5.33 min and TFMPP; 13.25–15.00 min. The column temperaturewas 36 °C. Following collection of the isolates, the mobile phasewas removed from the sample fractions via rotary evaporation inaddition to two lots of water addition/rotary evaporation toremove any TFA. Samples were dissolved in 1 mL of DI before freez-ing in liquid nitrogen and freeze-dried overnight. All samples (fromboth Cases 1 and 2) were treated identically throughout all steps ofpreparation, treatment, HPLC methodology and analysis.

2.3. Nuclear Magnetic Resonance Spectroscopy

1H and 13C NMR spectra were obtained using a Bruker Biospin300 MHz spectrometer (Bruker Biospin AG, Switzerland) operating at75.5 and 300 MHz, respectively.

2.4. Gas Chromatography–Mass Spectrometry

Combined GCMS analyses were performed by the NT police prior tothe samples via an Agilent GCMS Instrument (7890A GC with 5975CMSD Series with a Triple-Axis Detector) coupled via a heated transferline,maintained at 280 °C. TheGCwas equippedwith a temperature pro-grammable split/splitless (PSS) injector which was programmed from100 to 300 °C at a rate of 40 °C min−1 and maintained at that tempera-ture for 9.3min. Onemicroliter aliquots of samplewas injected and chro-matographic separation performed using a DB1-ms (Agilent J&Wsupplied by Thames Restek UK Ltd., Saunderton, UK) column; 15 m inlength, 0.25 mm in diameter with a 0.25 pm film thickness. The ovenwas maintained at 100 °C for 1 min, heated at a rate from 40 °C min−1

to 300 °C and maintained at that temperature for 3 min. Helium carriergas was operated at a constant flow rate of 2 mL min−1. The ion sourcewas maintained at a temperature of 280 °C with an electron energy of70 eV and an emission current of 60 µA. Data were acquired over arange mlz 35–500 at a rate of two scans per second using a Turbomass4.5 data system.

2.5. Isotope Ratio Mass Spectrometry

2.5.1. Bulk 13C and 15N isotope analysisBZP and TFMPP fromeach tabletwere analyzed for carbon andnitro-

gen isotopic composition in triplicate. Samples were weighed (0.05–0.15 mg) into tin capsules and palletized. Isotope data were acquiredby combusting samples at 1050 °C in a Sercon Europa EA-GSL elementalanalyzer. The CO2, NOx and H2O produced during the combustion werecarried in a He flow through a reduction reactor filled with copper at650 °C to reduce NOx to N2 then through an Anhydrone® magnesiumperchlorate trap to remove water. CO2 and N2 gases were chromato-graphically separated and fed into a Sercon Hydra 20–22 isotopemass spectrometer. The ratios of 13C/12C and 15N/14N from the solid

r drugs; BZP and TFMPP plus MDMA.

zylpiperazine and trifluoromethylphenylpiperazine tablets using δ13Cijus.2014.08.003

3N.M. Beckett et al. / Science and Justice xxx (2014) xxx–xxx

samples were obtained. Measured isotope abundance values were scalecalibrated to Vienna Pee Dee Belemnite (VPDB) (13C) and Air (15N)based on 2-point end-member normalization using contemporaneouslyanalyzed international referencematerials (RMs) obtained from the In-ternational Atomic Energy Agency (IAEA, Vienna, Austria): IAEA-CH-6(δ13CVPDB = −10.45‰) and IAEA-CH-71 (δ13CVPDB = −32.15‰) forcarbon and IAEA-N1 (δ15NAIR = +0.43‰) and IAEA-N2 (δ15NAIR =+20.35‰) for nitrogen. In addition, in-house standards sucrose andammonium sulfate were analyzed in duplicate throughout the analyti-cal sequence as quality control checks.

3. Results and discussion

An examination into the potential of IRMS as an investigative toolthrough the isotopic analysis of 13C and 15N composition of 23 tabletscontaining both BZP and TFMPP was conducted. Northern Territory po-lice seized the tablets on separate occasions from the NT district,Australia in 2012 (Case 1: 16 tablets and Case 2: 7 tablets). The identityof the active pharmaceutical ingredients (BZP and TFMPP) was deter-mined by GCMS analysis (performed by the police prior to the authorsreceiving the samples) ofwhich the chromatograms appeared very sim-ilar other than the inclusion of caffeine in Case 1 tablets. No suspectedlink between the two seizures was suggested. Physically the pills werevery similar; light pink/red in color and some were poorly tabletedand suggestive of having being ‘home-made’ as opposed to profession-ally tableted. No definitive or complete logoswere evident on any of thetablets, a vitamin-like odor and hydroscopic nature were observed fromall of the tablets. BZP and TFMPP were isolated (HPLC) from each indi-vidual tablet and an investigation into the detection of differences orsimilarities in the isotopic signatures of BZP and TFMPP was conducted[33]. To ensure reliability of the isolation method and integrity of thesamples under investigation, potential fractionation as a result of theHPLC isolation method was investigated. The 13C and 15N isotopic com-position of BZP and TFMPP standards were acquired from samples pre-and post-isolation. Standard sampleswere subjected to the exactmeth-od and workup by which the case samples were isolated from. Theresulting isotopic data are presented in Fig. 2. A two-sample t-test wasperformed to compare means of each sample group (BZP Standard:BZPHPLC, TFMPP Standard: TFMPPHPLC). A small but significant differ-ence was identified for both pre- and post-carbon and nitrogen samplesat the 95% confidence level (mean difference BZP: δ13CVPDB × 103 =0.200, δ15NAIR × 103 = 0.900 and TFMPP: δ13CVPDB × 103 = 0.367,δ15NAIR × 103 = 0.400). This slight difference can likely be explained

Fig. 2. a) Two-sample t-test of δ13C values fromBZP standard (×) (prior toHPLC) and BZPHPLC (Oand BZP HPLC (O) (post HPLC).

Please cite this article as: N.M. Beckett, et al., Isotopic profiling of seized benand δ15N stable isotopes, Sci. Justice (2014), http://dx.doi.org/10.1016/j.sc

by residue impurities present in the standards (1,4-dibenzylpiperazinein BZP for example). The values obtained for the standards showedgreater within variation, likely due to the impurities. The HPLC sampleshad been ‘cleaned up’ and reveal more constrained δ-values that fellwithin the range of the standards pre-HPLC. The same was apparentfor the TFMPP standards.

The results of carbon and nitrogen isotope analysis of BZP andTFMPP from the tablets are summarized in Table 1. Each data pointrepresents the mean of triplicate analyses (uncertainty is the standarddeviation from triplicate measurements). For BZP δ13C values varied ina narrow range between −27.8 and −28.5‰ and a larger range forδ15N between 0.2 and 3.1‰. Mean and standard deviation values forCases 1 and 2 were; δ13CVPDB = −28.1 ± 0.2 and δ15NAIR = 1.5 ±1.1‰ and δ13CVPDB = −28.2 ± 0.1 and δ15NAIR = 1.4 ± 0.7‰, respec-tively. The δ13C and δ15N values obtained for TFMPP varied between−26.8 and −28.9‰ and between −2.0 and −6.5‰, respectively.Mean and standard deviation TFMPP values for Cases 1 and 2 were;δ13CVPDB = −27.1 ± 0.2 and δ15NAIR = −7.45 ± 0.5‰ andδ13CVPDB = −28.7 ± 0.1 and δ15NAIR = −2.56 ± 0.4‰, respectively.

The BZP and TFMPP isolated from each tablet were structurally iden-tical (for the respective molecules (Fig. 1)) and it is the isotopic compo-sition of these molecules that may show variability between thecorresponding piperazine analogue samples. BZP is typically synthe-sized from piperazine and an aromatic moiety such as a benzyl deriva-tive, commonly benzyl chloride (Fig. 3) [34]. Depending on the originof the precursors (Precursor's X and Y for example) contributing theatoms composing the piperazine analogues (and provided syntheticfractionation effects are reproducible) the 13C and 15N compositionmay be suggestive of a common origin or allow discrimination betweencase group ormore specifically production batch. For the purpose of thispaper a distinction is made with regard to ‘production batch’ versus‘tableting batch’. Both provide important forensic information howeverthe isotopic data discussed refers to the potential linking or discriminat-ing of ‘production batches’ of the individual piperazine analogues. Thereare numerous scenarios or propositions that can be alluded to with re-spect to the ‘tableting batches’ however these would be speculativeand will not be discussed further.

Billault et al. [11] demonstrated that 13C and 15N analysis of 45 au-thentic MDMA samples synthesized via various clandestine methodsand reaction conditions, could discriminate between the samples.Based on the 15N composition of MDMA and the 13C and 15N of N-precursors, Billault et al. [11] showed grouping of the samples, reflectingreaction conditions.Work by Buchanan et al. [21] investigated the use of

) (post HPLC) and b) Two-sample t-test of δ15N values fromBZP Standard (×) (prior toHPLC)

zylpiperazine and trifluoromethylphenylpiperazine tablets using δ13Cijus.2014.08.003

Table 1δ13C and δ15N values for the BZP and TFMPP isolated from the tablets. Mean values of trip-licate analysis.

BZP TFMPP

Sample δ13C (‰) δ15N (‰) Sample δ13C (‰) δ15N (‰)

1 −27.79 1.98 1 −27.24 −8.252 −28.06 1.51 2 −26.81 −7.413 −27.90 2.80 3 −27.07 −8.054 −27.95 3.07 4 −27.50 −7.835 −28.22 3.10 5 −26.96 −8.206 −28.19 2.53 6 −27.29 −7.607 −28.03 2.34 7 −26.81 −7.778 −28.11 0.25 8 −27.01 −7.629 −28.14 0.60 9 −27.12 −6.9110 −27.85 0.82 10 −27.06 −6.7311 −27.98 0.99 11 −27.16 −7.1012 −28.19 1.36 12 −27.03 −7.1113 −28.43 0.58 13 −27.06 −7.0514 −28.54 0.20 14 −27.08 −6.9115 −28.05 0.48 15 −28.59 −2.7716 −28.02 1.29 16 −28.64 −2.1917 −28.07 0.81 17 −28.62 −2.3018 −28.16 2.72 18 −28.78 −2.6219 −28.38 1.28 19 −28.88 −3.0720 −28.28 0.96 20 −28.81 −2.3821 −28.13 1.35 21 − –

4 N.M. Beckett et al. / Science and Justice xxx (2014) xxx–xxx

IRMS as ameans to discriminate 18 batches of authenticMDMA synthe-sized via three different preparativemethods from a common precursorsource. The authors concluded that the analysis of the δ2H data alonewas powerful enough to accurately discriminate between the threeroutes employed. They do however acknowledge the discriminatingpower observed in their studymaynot extrapolate to clandestinely syn-thesized MDMA and further research is required. Iwata et al. [18] de-scribed a method for linking MA seizures using 13C and 15N isotopiccomposition based on a pooled standard deviation (sp) criterion beingless than ‘6sp square’. A bivariate analysis classified samples from 10cases into 7 clusters, presumably representing different origins. Threeof the clusters represented two independent seizures and therefore sup-ported the suspected links initially established through impurity profil-ing and prior investigative information.

Palhol et al. [35] analyzed the 15N composition of 43MDMA samplesoriginating from numerous seizures (a large range between −16 and19‰ was observed). A correlation between δ15N values and certainphysical features of the tablets including tablet logos was reported.The large variation in δ15N values and physical correlations enabled

Fig. 3. Production of BZP synthesis before tableting

Please cite this article as: N.M. Beckett, et al., Isotopic profiling of seized benand δ15N stable isotopes, Sci. Justice (2014), http://dx.doi.org/10.1016/j.sc

Palhol et al. [35] to make the assumption that tablets from different sei-zures probably originated from the same clandestine manufacturingsource.

Comparing the δ-values obtained within the BZP from the two sepa-rate cases, no statistical difference could be determined between thecase samples based on a bivariate analysis of carbon and nitrogen data(Fig. 4). Overlapping and close clustering of data points between thetwo cases is evident. Thus these data sets cannot be discriminated bycase, suggesting a common source of manufacture or ‘productionbatch’. Canonical Discriminant Analysis (CDA) demonstrated that ap-proximately 50% of the samples were mis-classified as the other case,again reinforcing the likelihood of a common manufacturing origin.Compared with authentic BZP samples from various precursor sources(Fig. 4), discrimination between the cases and authentic BZP was evi-dent. Fig. 4 shows that Cases 1 and 2 are clustered together and separatefrom the four authentic sources thus providing evidence of a commonmanufacturing origin.

BZPwas legal inmost countries until 2008 andflooded themarket asa ‘natural and safe alternative’ to common party drugs such as MDMAand MA [31]. Since BZP was controlled it is probable that there are sup-plies ofwhatwere once legitimate tablets still circulating andnowavail-able for illegal purchase. If this is the case, it is possible to speculate thatthe BZP examined in this study originated from the same source i.e. lab-oratory or even the same synthetic batch of BZP tablets. Alternatively, ifthe BZP was synthesized in a clandestine laboratory or imported, theisotopic composition again supports the possibility of a commonmanufacturing source or synthetic batch.

Prior to being made illegal, TFMPP was available for purchasefrom a variety of sources and commonly tableted with BZP as anoth-er ‘legal high’ alternative and marketed as A2 or Frenzy [36]. Thelegal status of TFMPP now varies throughout the world. AlthoughTFMPP is not scheduled under Australian federal law, many coun-tries such as the UK, Canada, Japan and New Zealand have scheduledTFMPP as an illicit/dangerous substance [37]. The presence of TFMPPwithin MDMA tablets and other illegal formulations appears to becommon [38].

Of note, statistical analysis of the TFMPP isotopic data revealed a sig-nificant difference between the cases based on the bivariate analysis ofcarbon and nitrogen. The bivariate scatter plot (Fig. 5) clearly revealedvisual discrimination of the samples based on case grouping and 100%correct classification was demonstrated through CDA. The δ-valuesshow a large variation between cases but appear to be homogenouswithin a grouping, exhibiting small δ-value ranges (Table 1). As men-tioned earlier the isotopic data provides information on the ‘production

with TFMPP, caffeine and other excipients [1].

zylpiperazine and trifluoromethylphenylpiperazine tablets using δ13Cijus.2014.08.003

Fig. 4. Bivariate plot displaying δ13C and δ15N results for BZP from Cases (♦) 1 and (●) 2,authentic BZP synthesized from sources (×) Alfa Aesar; (+) Sigma; (▼) MP Biomedicaland (■) BZP standard. No visual discrimination is evident between Cases 1 and 2.

5N.M. Beckett et al. / Science and Justice xxx (2014) xxx–xxx

batch’more so than the ‘tableting batch’ and therefore the data are sug-gestive of different sources of manufacture or ‘production batches’.These data does not necessarily transpose to reflecting different‘tableting batches’ and consequently provides no further informationon establishing a link or discriminating between the two cases basedon the TFMPP data. Compared with authentic TFMPP samples (Fig. 5),discrimination between Cases 1 and 2 and authentic TFMPP was ob-served and again this may support a proposition that the samples orig-inated from different ‘production batches’.

Fig. 5. Bivariate plot displaying δ13C and δ15N results for TFMPP from Cases (●) 1 and (▼)2, authentic TFMPP synthesized from sources (×) 1) Alfa Aesar; (+) 2) Sigma; and TFMPP(♦) standard. Visual discrimination is evident between all TFMPP groups.

Please cite this article as: N.M. Beckett, et al., Isotopic profiling of seized benand δ15N stable isotopes, Sci. Justice (2014), http://dx.doi.org/10.1016/j.sc

The δ15N values within each TFMPP grouping showed small vari-ances (Case 1: δ15NAIR = −7.5 ± 0.5‰, Case 2: δ15NAIR = −2.6 ±0.3‰). Casale et al. [39] highlighted that synthetic methods can causevariation in 15N values due to fractionation as apposed to the 15N com-position of the precursors. Given that the δ15N values are relativelyconstrained within a group it seems reasonable to assume that whatev-er fractionation occurred it did so in a reproducible manner. The sepa-rate clusters evident in Fig. 5 therefore reflect the isotopic differencesoriginating from the different precursor sources. Nic Daeid et al. [16]showed discrimination ofmephedrone batches synthesized fromdiffer-ent sources (using the same preparative method) by carbon and hydro-gen isotopic composition. Although their aims were to determinelinkage relationships of ‘precursor–product’, their study demonstratedthe ability to discriminate between the two precursor supplier sourcesbased on the different δ-values of the products (Sources 1 (S) and 2(A): δ13CVPDB = −23.21 ± 0.11, δ2HVSMOW = 55.2 ± 2.2‰ andδ13CVPDB = −29.41 ± 0.24, δ2HVSMOW = 29.4 ± 1.3‰, respectively.).

The difference in the nature of the isotopic data obtained for BZP andTFMPP is interesting. For the BZP examined in this study the isotopiccompositiondoes not provide ameans todiscriminate between sampleswhereas the data obtained for TFMPP reflect the case grouping. Thereare numerous possibilities that may explain the different nature of thedata following the likely scenario of different/same sources, such asthe tableting process (addition of multiple TFMPP pills, batches orsources to the BZP tablets), multiple supply sources of compounds, de-pletion and/or blending of a variety of compounds, different clandestinelaboratories, and different TFMPP preparative methods. Given that thetablets were very similar physically (appearance, composition, color,odor), it is reasonableto suggest that there may be a link between thetwo cases based on the similar BZP isotopic content. However it is notpossible to determine or support the proposed link due to the uncer-tainty surrounding the TFMPP sources.

4. Conclusions

The ability to discriminate between sources and/or identify the ori-gins of illicit drugs is a goal of forensic scientists. Although not routinelyused for illicit drug investigations, IRMS information has been obtainedand its application demonstrated utilizing the stable isotopes of carbonand nitrogen. This case study presents an insight into the potential ofIRMS to acquire information that other more routinely used analyticaltechniques such as GCMS fail to provide.

Analysis of the 13C and 15N isotopic composition of seized BZP andTFMPP containing tablets reveal findings that are consistent with atleast two possible scenarios. First, the two seizures/cases are not linkedalthough a common source or ‘production batch’ of BZP cannot be ex-cluded; second, the two seizures/cases are linked with the differencein TFMPP signatures being due to two different ‘production batches’ ofTFMPP being used for tableting with a single batch of BZP. The interest-ing and conflictingdata highlights a need for cautionwhen investigatingmultiple compounds tableted together with reference for intelligencepurposes. The application of this type of preliminary isotopic researchinto unauthentic, clandestinely synthesized or sourced BZP/TFMPP ispromising and work within the area is ongoing.

Acknowledgments

We are grateful for an Australian Postgraduate Award scholarship(N.B.) that allowed this research to be conducted. Additionally, the Insti-tute for Glycomics, Gold Coast campus and the School of Natural Sci-ences, Nathan campus, Griffith University are acknowledged for theirfinancial support. Finally, Matt Hickson from the Northern Territory Po-lice is acknowledged for providing the samples analyzed within thisstudy and Faith J. Rose for her HPLC analysis of the samples.

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6 N.M. Beckett et al. / Science and Justice xxx (2014) xxx–xxx

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zylpiperazine and trifluoromethylphenylpiperazine tablets using δ13Cijus.2014.08.003