mdma.impurity.extraction.optimization.pdf

Forensic Science International 132 (2003) 182–194

Optimization of extraction parameters for the chemical proﬁling of

3,4-methylenedioxymethamphetamine (MDMA) tablets

Pascal Gimeno, Fabrice Besacier * ,

Huguette Chaudron-Thozet

Laboratoire de Police Scientiﬁque de Lyon, 31 Avenue Franklin Roosevelt, 69134 Ecully, France

Received 9 October 2002; received in revised form 6 January 2003; accepted 10 January 2003

Abstract

The extraction of impurities from illegally produced 3,4-methylenedioxymethamphetamine (MDMA) has been studied in

order to optimize the parameters. Two different MDMA samples were used. Particular attention was paid to the inﬂuence of the

pH, the evaporation step, and the sample storage. The method used was an extraction of impurities by diethyl ether from a buffer

solution at pH 11.5, followed by gas chromatography (GC) mass spectrometric (MS) analyses after a dryness concentration

under monitored conditions of the ethereal extract. Repeat extractions of the same sample gave an average relative standard

deviation (RSD) of less than 8.5% within day and less than 10.5% between days.

Keywords: 3,4-Methylenedioxymethamphetamine (MDMA); Impurities; Gas chromatography; Mass spectrometry; Proﬁling

1. Introduction

amphetamine or methamphetamine samples like the paper

of Sten et al. [3] , only few articles are concerned with

MDMA [4–7] . More authors prefer to focus on the identi-

ﬁcation of impurities in freshly prepared MDMA samples

via different synthesis routes and give us analytical data of

precursors, intermediates and reaction by products [8–18] .

Among published extraction processes, one consists in

dissolving 5 mg of crushed MDMA tablets into 1 ml of

redistilled diethyl ether [4] . The supernatant is then taken

off and evaporated to dryness before adding 0.1 ml of

methyl alcohol for GC–MS analyses. Another paper pre-

sents the impurities found in MDMA and MDEA street

samples [5] . The extraction method used consists in dis-

solving 150–300 mg of each sample into 5 ml of phosphate

buffer (pH ¼ 7), in order to have about 80 mg of active

substance, the extraction being carried out with 1 ml of

diethyl ether containing heneicosane (C21) as internal

standard. Other authors also use a phosphate buffer

(pH ¼ 6 [6] or pH ¼ 9 [7] ) to dissolve MDMA powders

whereas organic impurities are extracted, respectively by

dichloromethane [6] and ethyl acetate [7] . In that last study,

comparison between liquid–liquid extraction (LLE) and

solid phase extraction (SPE) for the proﬁling of ecstasy

tablets is also discussed.

3,4-Methylenedioxymethamphetamine (MDMA) is an

illicit synthetic, psychoactive substance possessing stimu-

lant and mild hallucinogenic properties. According to Euro-

pol, in 2000, 17.4 millions of ecstasy tablets were seized in

the member states of the European Union, corresponding to

an increase of almost 50% compared with 1999. Signiﬁcant

increases were observed in Austria (420%), Finland (394%),

Greece (1803%), Ireland (163%), Italy (86%), The Nether-

lands (50%), Spain (64%) and Sweden (152%) [1] .

In order to know synthesis schemes used by clandestine

laboratories, an analytical method has been developed in

order to identify by gas chromatography–mass spectrometry

(GC–MS) the various impurities present in ecstasy samples

[2] . Nevertheless, several extraction parameters needed to be

optimized in order to improve the reproducibility of the

method suggested.

As a matter of fact, if many publications deal with a

detailed impurity extraction process for the proﬁling of

Corresponding author. Tel.: þ 33-47-286-8982.

E-mail address: fabrice.besacier@interieur.gouv.fr (F. Besacier).

doi:10.1016/S0379-0738(03)00019-7

P. Gimeno et al. / Forensic Science International 132 (2003) 182–194

183

2. Materials and methods

were evaporated to dryness under a low nitrogen ﬂow rate).

Five hundred microliter of diethylether containing n-dode-

cane as ISTD at 0.113 ppm were added to the tube, shaken for

a few seconds, and transferred to a micro-vial for proﬁle

analysis. In order to avoid impurity degradation, the extracts

were injected the same day they were prepared.

2.1. Gas chromatography and mass spectrometry

All analyses were carried out on a Thermoﬁnnigan GC

trace 2000 gas chromatograph interfaced with an ion trap

Polaris mass spectrometer. Two microliters of each extract

were injected according to the splitless mode using a Thermo-

ﬁnnigan AS 2000 autosampler. The column was a Supelco

PTA5 capillary column (cross-linked poly 5% diphenyl/95%

dimethylsiloxane); 30 m 0 : 32 mm ð i : d : Þ 0 : 5 mm ﬁlm

thickness. The oven temperature was programmed as follows:

50 8Cfor1min,58Cmin 1 to 150 8C for 12 min, and

15 8Cmin 1 to 300 8C for 10 min. The injection port and

transfer line temperatures were, respectively 280 and 275 8C.

The ion source temperature was set at 200 8C, and the helium

carrier gas ﬂow rate was ﬁxed at 1 ml min 1 . The mass

spectrometer was tuned on electron impact ionization (Ei)

for low-mass analysis for detection of each impurity. For the

reproducibility and the optimization studies, selected ion

monitoring (SIM) was used on the most intense impurity

mass fragments. In order to preserve the MS ﬁlament life, the

mass spectrometer was switched-off during elution of the

major compounds.

3. Results and discussion

3.1. Identiﬁcation of impurities

The chromatographic proﬁles of samples RefA and RefB

are shown in Figs. 1 and 2 , respectively. Table 1 gives peak

identity and mass spectral data for impurities used in this

study. Target ions used in the SIM mode are bold typed in the

table.

3.2. Overall reproducibility of the method

Results were expressed giving relative standard deviation

(RSD) of each peak area, acquired according to SIM mode

and after normalization, i.e. dividing all areas in a run by the

peaks sum. Peaks used for this study were peaks 1–10, for

both samples RefA and RefB ( Figs. 1 and 2 ). However,

impurity 6 is not present in sample RefB.

2.2. MDMA materials

Two different MDMA samples (RefA and RefB) have been

used for the optimization of extraction parameters. These

samples consisted of 35% MDMA Phosphate diluted with

lactose (RefA), and of 99% MDMA hydrochloride (RefB).

3.2.1. Gas chromatography repeatability

Five injections of the same extract from sample RefA

gave a minimum relative standard deviation of 1.8% to a

maximum of 7.0%, the average value being 4.9%. The same

study on sample RefB gave a minimum relative standard

deviation of 0.9% to a maximum of 9.3%, the average value

being 6.1%.

2.3. Standard extraction method

An amount of sample equivalent to 10 mg of pure MDMA

hydrochloride was weighed and dissolved into 2 ml of a buffer

solution at pH 11.5 and shaken for 10 min at 1800 rpm. The

extraction was performed adding 3 ml of diethylether and

shaking for another 10 min. After centrifugation, the organic

layer was transferred to a conic tube and evaporated to dryness

under monitored conditions at room temperature (extracts

3.2.2. Overall reproducibility (extraction and gas

chromatography)

3.2.2.1. Within day. Four extractions by day during 4 days

were made from samples RefA and RefB and analyzed. The

relative standard deviations for RefA sample varied from 3.5

Table 1

Target impurities in MDMA samples

Impurity name

Ei mass spectral data

Peak no.

1,3-Benzodioxole C 7 H 6 O 2 ; MW 122

121/122, 63/64

3,4-Methylenedioxytoluene C 8 H 8 O 2 ; MW 136

135/136, 78/77, 51

Safrole C 10 H 10 O 2 ; MW 162

162, 104, 131, 77, 51

Piperonal C 8 H 6 O 3 ; MW 150

149/150, 121, 63, 91

Isosafrole C 10 H 10 O 2 ; MW 162

162, 104, 131, 77, 51

3,4-Methylenedioxy-N-methylbenzylamine C 9 H 11 NO 2 ; MW 165

135/136, 164/165, 44, 77

p-Methoxymethamphetamine (pMMA) C 11 H 17 NO; MW 179

58, 121, 78, 91

1,2-Methylenedioxy-4-(2-N-methyliminopropyl)benzene C 11 H 13 NO 2 ; MW 191

56, 191, 135, 77

N,N-Dimethyl-(1,2-methylenedioxy)-4-(2-aminopropyl)benzene C 12 H 17 NO 2 ; MW 207

72, 56, 44, 73, 58, 70

N-Methyl-(1,2-methylenedioxy)-4-(1-ethyl-2-aminopropyl)benzene C 13 H 19 NO 2 ; MW 221

58, 162, 77, 135, 194

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P. Gimeno et al. / Forensic Science International 132 (2003) 182–194

Table 2

Within day repeatability (RSD%)

Sample/peak

Average

RefA

9.2

6.4

7.1

13.3

8.7

3.5

5.4

9.4

7.8

6.3

7.7

RefB

10.3

8.1

11.0

10.3

7.5

6.9

4.6

8.7

5.7

8.1

Table 3

Between days reproducibility (RSD%)

Sample/peak

Average

RefA

12.3

8.4

6.6

16.3

10.9

6.9

7.2

12.4

13.0

7.4

10.2

RefB

12.1

9.9

10.9

10.6

10.5

8.9

7.2

11.1

8.2

9.9

to 13.3% with an average of 7.7%, and similar results were

obtained for RefB sample with a minimum relative standard

deviation of 4.6% to a maximum of 11.0% and an average of

8.1%. Table 2 gives the results obtained for each target

impurity.

from 7.2 to 12.1% with an average of 9.9%. Table 3 gives the

results obtained for each target impurity.

3.3. Optimization of extraction parameters

3.3.1. Inﬂuence of the pH

A buffer solution of glycocoll–NaCl/NaOH was used for

the pH study. The pH was changed from 8.4 to 12.6 in

increments of 0.2. Results point out that almost all target

impurities were strongly inﬂuenced by the buffer pH. The

extracted impurity amounts increased with the pH from 8.4

3.2.2.2. Between days. Four extractions by day during four

days were made from samples RefA and RefB and analyzed.

If we consider sample RefA, the relative standard deviations

varied from 6.6 to 16.3% depending on the impurity, with an

average value of 10.2%. For RefB sample, values varied

Fig. 3. Inﬂuence of pH on impurity 3.

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