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September 10, 2011

Identification of Phenethylamines and Methylenedioxyamphetamines Using Liquid Chromatography Atmospheric Pressure Electrospray Ionization Mass Spectrometry

Identification of Phenethylamines and Methylenedioxyamphetamines
Using Liquid Chromatography Atmospheric Pressure
Electrospray Ionization Mass Spectrometry

Adrian S. Krawczeniuk
U.S. Department of Justice
Drug Enforcement Administration
Northeast Laboratory
99 - 10th Avenue, Suite 721
New York, NY 10011
[email: Adrian.S.Krawczeniuk -at- usdoj.gov ]

ABSTRACT: A liquid chromatography - mass spectrometric (LC/MS) procedure utilizing atmospheric pressure electrospray ionization (API-ES) was developed for the identification of phenethylamines, methylenedioxyamphetamine analogs, and other related compounds of forensic interest. An evaluation of three Phenomenex Synergi C-18 columns (Hydro-RP, Polar-RP, Fusion-RP) was performed using 22 compounds of interest to determine optimum selectivity. The method utilizes an isocratic buffered system of 10 mM ammonium formate pH 3.7 - acetonitrile along with diode array detection at 280 nm and 210 nm. Ionization is effected via electrospray in positive mode, resulting in a protonated pseudomolecular ion for the compounds of interest. Electrospray parameters were optimized via flow injection analysis and collision induced dissociation experiments were performed to optimize fragmentation of the compounds of interest. Sample preparation was minimal, and there was no need to derivatize.

KEYWORDS: Phenethylamines, Methylenedioxyamphetamine Analogs, LC/MS, Electrospray, Collision Induced Dissociation, Forensic Chemistry

Introduction

Gas chromatography/mass spectrometry (GC/MS) is considered the standard technique for the identification of sympathomimetic amines such as phenethylamines and structurally related substituted compounds [1-5]. However, many of these compounds exhibit mass spectra with a very predominant base peak and very low molecular and fragment ions, which can make the identification challenging. Software normalization techniques have been employed in discriminating mass spectra of amines by removing the dominant base peak and normalizing the spectrum to a lower residual ion [5]. Derivatization techniques utilizing perfluorinated anhydrides such as heptafluorobutyryl (HFB), pentafluoropropionyl (PFP), or trifluoroacetyl (TFA), or silylating derivatives such as BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) and MSTFA (N-methyl-N-trimethylsilyltrifluoroacetamide), have also been widely employed, and both improve specificity and produce more readily identifiable mass spectra [6-7].

A liquid chromatograph coupled with atmospheric pressure ionization (LC-API), in either electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) mode, provides an alternative technique to GC/MS for the identification of illicit drugs. LC/MS has been used successfully to analyze a broad range of compounds, with applications in forensic and clinical toxicology [8-12], anti-doping testing [13], and therapeutic drug monitoring [14]. LC/MS is ideal for thermolabile, low molecular weight compounds, non-volatile compounds, and/or highly polar drugs, eliminating the need for derivatization.

Atmospheric pressure ionization (API) is a relatively soft ionization technique generating either protonated [M+H]+ or deprotonated pseudomolecular ions [M-H]-, or multiply charged ions; these are formed through ion evaporation in ESI, and through gas-phase chemical ionization in APCI. API sources yield low fragmentation, which would normally preclude the use of single quadrupole instruments. However, in-source collision dissociation (CID) can take place in the ion source, allowing for fragmentation of analyte ions via collisions with neutral molecules from residual solvent and gas molecules. This results in bond cleavages and rearrangements that are representative of the molecular structure of the molecule.

This study presents an LC/MS method using electrospray ionization (ESI) for the separation and confirmation of phenethylamines (PEAs), methylenedioxyamphetamines (MDAs), and other compounds routinely encountered in illicit drug seizures. HPLC separations were optimized using three different C-18 stationary phases, and CID experiments were performed in order to obtain mass spectra with fragmentations characteristic for each compound examined.

Experimental

LC/MS Methodology
Analyses were performed using an Agilent Technologies 1100 series high pressure liquid chromatograph (HPLC), including a quarternary pump, vacuum degasser, autosampler, thermostatted column compartment, diode array detector, and coupled to an Agilent Technologies 1100 series Model SL single quadrupole mass spectrometer equipped with an electrospray ionization interface. Nitrogen drying gas was generated using a nitrogen generator (Agilent Technologies 5183-2003) coupled to a Jun Air air compressor.

Chromatographic separations were evaluated using three different Phenomenex Synergi columns (15 cm x 3.0 mm, 4 μ 80 A) - Hydro-RP, Polar-RP and Fusion-RP. A mobile phase of 10 mM ammonium formate pH 3.7: Acetonitrile (88:12) delivered at a flow rate of 0.5 mL/minute was used to elute the compounds of interest. The column temperature was thermostatically controlled at 40 °C. An injection volume of 2 μL was used.

Mass analyses were performed in scan mode from a mass range m/z 50 - 350 measuring positive pseudomolecular ions. The fragmentor was set at 150 V for all compounds except phenethylamine which was run at 70 V in order to observe the pseudomolecular ion. Spray chamber parameters were as follows: 12.0 L/minute drying gas, 350 °C drying gas temperature, 40 psig nebulizer, 4000 V capillary voltage.

All illicit samples examined were dissolved in the mobile phase and filtered thru a 0.45 μ nylon membrane filter prior to analysis. Flow injection analysis was performed on all compounds examined by varying the fragmentor voltage from 100 - 240 V in increments of 20 V. Nebulizer pressure, capillary voltage, and drying gas flow were operated as per manufacturer’s specifications. Complete system control and data evaluation was carried out using the Agilent Chemstation for LC/MS.

Reagents
All drug standards were obtained from the reference collection of the DEA Northeast Laboratory. Standards were prepared at a concentration of 0.05 mg/mL diluted in 10 mM ammonium formate pH 3.7. Ammonium formate (99.995+ %), formic acid (95 - 97 %), and acetonitrile (LC/MS Chromasolv grade) were obtained from Sigma Aldrich, St. Louis, MO. Ultrapure water from a Millipore Gradient 10-Elix 3 system (Billerica, MA) was used to prepare all buffers in the study.

Results and Discussion

Optimization of the HPLC conditions was performed using an ammonium formate buffer at pH 3.7 and acetonitrile as the organic modifier. Acetonitrile was chosen as opposed to methanol because it gave more symmetrically shaped peaks and efficiently resolved the compounds of interest. PEAs and MDAs are ideal candidates for positive ion ESI because low pH buffers completely ionize basic compounds (i.e., resulting in protonated species). A total of 22 compounds including structurally similar sympathomimetic amines, MDAs, and adulterants routinely encountered in illicit seizures were evaluated on three Phenomenex Synergi C-18 columns (Hydro-RP, Polar-RP and Fusion-RP).

Selectivity data for each of the three columns evaluated are listed in Tables 1 - 3. All three columns gave similar selectivities for the 12 most commonly encountered substrates (phenylpropanolamine, phenethylamine, ephedrine, pseudoephedrine, methylephedrine, amphetamine, dimethylamphetamine, methamphetamine, phentermine, 3,4-MDA, 3,4-MDMA, 3,4-MDEA, and MBDB) (see Tables 1 - 3 and Figures 1 - 3). The Polar-RP column (an ether linked phenyl phase with hydrophilic endcapping) exhibited slightly more retentiveness for the N-substituted MDA analogs MDEA, MBDB, and N,N-dimethyl-MDA, along with dimethylamphetamine and ketamine. The adulterant caffeine, commonly encountered in MDMA seizures submitted to our laboratory, was retained on the Polar-RP column, but co-eluted with MDMA on the Hydro-RP and Fusion-RP columns (Tables 1 - 3). Case submissions containing both illicit tablets and powders were analyzed using the established LC/MS procedure (see Figures 13 - 14). Results were verified using a GC/MS method. Both the Hydro-RP and Polar-RP columns have been used interchangeably for routine case submissions, with good success.

Figures 4 - 10 show the mass spectra of 17 PEAs and MDAs examined under the ESI conditions specified. All compounds examined (except phenethylamine) exhibited a protonated pseudomolecular ion using a fragmentor of 150 V. Decreasing the voltage to 70 V revealed the protonated pseudomolecular ion for phenethylamine.

Methamphetamine and phentermine exhibit similar GC/MS fragmentation patterns, but are readily differentiated under ESI conditions. Both compounds are easily resolved on the Hydro-RP and Fusion-RP columns (see Figure 3). These isomers are more closely resolved on the Polar-RP column with a resolution of 1.55 (HPLC) and 1.22 (MS) using the half-width method calculation. Methamphetamine and phentermine both exhibit a pseudomolecular ion of m/z 150, but are easily differentiated by their characteristic fragment ions, with methamphetamine exhibiting a m/z 119 product ion and phentermine exhibiting a m/z 133 product ion (see Figure 4). The ability to resolve these isomeric pairs chromatographically and differentiate them by their mass spectral fragmentation patterns allows for facile identification of these two compounds. Phentermine and 4-methoxymethamphetamine are unresolved on the three columns tested - but this combination has never been encountered at our laboratory (see Figure 3).

The MDAs were resolved on all three columns (see Figure 1). N-hydroxy-3,4-MDA was strongly retained on the Hydro-RP, and eluted in 44 minutes. However, the Polar-RP and Fusion-RP columns offered a more efficient elution, with retention times less than eleven minutes. N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) is readily resolved from its regioisomeric MDA derivatives (i.e., 3,4-MDEA, and N,N-dimethyl-3,4-MDA) on all three columns. All three compounds exhibit a protonated pseudomolecular ion at m/z 208. 3,4-MDEA and N,N-dimethyl-3,4-MDA exhibit indistinguishable ESI mass spectra (Figure 7). 3,4-MDEA and MBDB are readily differentiated by their product ions, with MBDB exhibiting product ions at m/z 177 and 135 while MDEA exhibits product ions at m/z 163 and 133 (see Figure 7).

3,4-MDA exhibits a pseudomolecular ion at m/z 180, with product ions at m/z 163, 133, and 105, while 3,4-MDMA exhibits a pseudomolecular ion and base peak at m/z 194, with similar product ions (see Figure 5). All the substituted MDA analogs examined (except 3,4-MDEA and N,N-dimethyl-3,4-MDA) are readily distinguishable by their pseudomolecular ions. In addition, all of the MDAs are resolved on all three columns, thereby allowing for differentiation even of 3,4-MDEA and N,N-dimethyl-3,4-MDA via retention time matching.

In the present study, a fragmentor voltage of 150 V was chosen in order to observe a protonated pseudomolecular ion and sufficient fragmentation product ions that would allow for conclusive identification of each compound examined. Table 4 provides a summary of the relative abundances of the five major ions for each compound examined. The protonated molecular ion was the base peak for 12 of the 22 compounds examined.

Flow injection analysis allows for direct sample injection into the mass spectrometer and was used in order to optimize API-MS parameters. This allowed for rapid method development. CID experiments via flow injection analysis were performed on all compounds by varying the fragmentor voltages from 100 - 240 V.

Varying the fragmentor voltages had the greatest impact on the rate of fragmentation as observed during the CID of 3,4-MDMA (Figure 12). The protonated pseudomolecular ion m/z 194 is most abundant at 100 V and gradually decreases as the fragmentor voltage is ramped to 240 V. At 100 V, the pseudomolecular ion is the base peak, and there are minimal fragment product ions. As the fragmentor voltage is increased, characteristic product ions are observed, and increase in intensity (Figure 11).

Fragmentor voltages were optimized for each respective compound (see Table 5). The sensitivity of higher mass ions was higher at lower fragmentor voltages, while the sensitivity of lower mass ions increased at higher fragmentor voltages. Area response sensitivity gradually decreased for compounds examined as a function of increasing fragmentor voltage (see Figure 15).

In-source CID has been shown to produce similar fragmentations as conventional CID in the collision cell of a tandem mass spectrometer (MS-MS) - but not necessarily of the same intensities. A requirement for in-source CID is a complete separation of the compounds being studied, as opposed to conventional CID using a tandem MS, where a precursor ion is specifically selected, followed by fragmentation [15,17,18]. A disadvantage of in-source CID is that since all ions are fragmented there is no mechanism to elucidate which product ions originated from which precursor ion [18]. In addition, no commercial in-source CID mass spectral libraries exist at present, requiring the user to create an in-house CID mass spectral library for the compounds of interest [16].

In conclusion, in-source fragmentation using a single quadrupole mass spectrometer allows for the positive identification of PEAs and MDAs. The instrumentation is user friendly, provides the ability to perform rapid method development using in-source CID, and offers extracted ion monitoring to deconvolute complex chromatograms. The LC/MS method has been implemented at our laboratory, and has been instrumental in confirming the presence of PEAs, MDAs, and common adulterants found in complex illicit mixtures. This provides a complementary and/or alternative means of identification of PEAs and MDAs.

Acknowledgments

Special thanks to Forensic Chemist Ramona S. Montreuil and Supervisory Chemist Ed J. Manning (both at this laboratory) for their editorial suggestions in reviewing this manuscript.

References

1. Noggle FT, Clark CR, DeRuiter J. Comparative analytical profiles for regioisomeric phenethylamines related to methamphetamine. Microgram 1991;24(4):76-91.

2. Noggle FT, Clark CR, Bouhadir KH, DeRuiter J. Methods for the differentiation of methamphetamine from regioisomeric phenethylamines. Journal of Chromatographic Science 1991;29:31-36.

3. Noggle FT, Clark CR, DeRuiter J. Liquid chromatographic and mass spectral analysis of methoxyamphetamine and methoxymethamphetamine. Journal of Chromatographic Science 1989;27:602-606.

4. DalCason TA. The characterization of some 3,4‑methylenedioxyphenylisopropylamines (MDA analogs). Journal of Forensic Sciences 1989;34(4):928-961.

5. Steeves JB, Gagne HM, Buel E. Normalization of residual ions after removal of the base peak in electron impact mass spectrometry. Journal of Forensic Sciences 2000;45(4):882-885.

6. Kaufmann MS, Hatzis AC. Electron impact mass spectrometry of N-substituted amphetamines. Microgram 1996;29(7):179-189.

7. Knapp DR, Editor. Handbook of Analytical Derivatization Reactions. John Wiley and Sons, New York, NY (1979).

8. Maurer HH. Liquid chromatography-mass spectrometry in forensic and clinical toxicology. Journal of Chromatography B: Biomedical Sciences and Applications 1998;713:3-25.

9. Bogusz MJ. Liquid chromatography-mass spectrometry as a routine method in forensic sciences: A proof of maturity. Journal of Chromatography B: Biomedical Sciences and Applications 2000;748:3-19.

10. Bogusz MJ, Kruger KD, Maier RD. Analysis of underivatized amphetamines and related phenethylamines with high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. Journal of Analytical Toxicology 2000;24:77-84.

11. Nordgren HK, Bech O. Direct screening of urine for MDMA and MDA by liquid chromatography-tandem mass spectrometry. Journal of Analytical Toxicology 2003;27:15-19.

12. Rohrich J, Kauert G. Determination of amphetamine and methylenedioxyamphetamine derivative in hair. Forensic Science International 1997;84:179-188.

13. Politi L, Groppi A, Polettini A. Applications of liquid chromatography-mass spectrometry in doping control. Journal of Analytical Toxicology 2005;29:1-14.

14. Day J, Slawson M, Lugo RA, Wilkins D. Analysis of fentanyl and norfentanyl in human plasma by liquid chromatography-tandem MS using electrospray ionization. Journal Analytical Toxicology 2003;27:513-516.

15. Venisse N, Marquet P, Duchoslav E, Dupuy JL, Lachatre G. A general unknown screening procedure for drugs and toxic compounds in serum using liquid chromatography electrospray-single quadrupole mass spectrometry. Journal of Analytical Toxicology 2003;27:7-14.

16. Marquet P, Venisse N, Lacassie E, Lachatre G. In-source CID mass spectral libraries for the general unknown screening of drugs and toxicants. Analysis 2000;28:925-934.

17. Niessen WMA. Advances in instrumentation in liquid chromatography-mass spectrometry and related liquid introduction techniques. Journal of Chromatography A 1998;794:407-435.

18. Basics of LC/MS Primer, Agilent Technologies (2001).

* * * * *

Table 1. Selectivity of Compounds Examined on Phenomenex Synergi Hydro-RP.

Compound

MS Rt (minutes)

RRt (Methamphetamine)

Niacinamide

1.93

0.32

Phenylpropanolamine

2.87

0.47

Acetaminophen

2.90

0.47

Phenethylamine

2.99

0.49

Ephedrine

3.72

0.61

Pseudoephedrine

3.73

0.61

Benzylpiperazine

4.08

0.67

Methylephedrine

4.22

0.69

Amphetamine

4.97

0.81

Caffeine

5.06

0.83

3,4-MDA

5.57

0.91

Methamphetamine

6.12

1.00

3,4-MDMA

6.66

1.09

Dimethylamphetamine

7.06

1.15

Phentermine

7.36

1.20

N,N-Dimethyl-3,4-MDA

7.62

1.25

4-Methoxymethamphetamine

7.64

1.25

Ethylamphetamine

8.50

1.39

3,4-MDEA

9.30

1.52

Ketamine

11.01

1.80

MBDB

12.30

2.01

N-Hydroxy-3,4-MDA

44.24

7.23

* * * * *

Table 2. Selectivity of Compounds Examined on Phenomenex Synergi Polar-RP.

Compound

MS Rt (minutes)

RRt (Methamphetamine)

Niacinamide

2.39

0.37

Phenylpropanolamine

3.15

0.49

Phenethylamine

3.22

0.50

Acetaminophen

3.65

0.57

Ephedrine

4.07

0.63

Pseudoephedrine

4.19

0.65

Methylephedrine

4.83

0.75

Benzylpiperazine

4.86

0.75

Amphetamine

5.05

0.78

3,4-MDA

6.30

0.98

Methamphetamine

6.44

1.00

Phentermine

6.84

1.06

Caffeine

7.88

1.22

3,4-MDMA

7.99

1.24

Dimethylamphetamine

8.20

1.27

4-Methoxymethamphetamine

8.34

1.30

Ethylamphetamine

8.79

1.36

N,N-Dimethyl-3,4-MDA

10.33

1.60

N-Hydroxy-3,4-MDA

10.59

1.64

3,4-MDEA

11.12

1.73

Ketamine

12.31

1.91

MBDB

13.10

2.03

* * * * *

Table 3. Selectivity of Compounds Examined on Phenomenex Synergi Fusion-RP.

Compound

MS Rt (minutes)

RRt (Methamphetamine)

Niacinamide

2.35

0.39

Phenylpropanolamine

3.52

0.52

Phenethylamine

3.58

0.53

Ephedrine

3.80

0.63

Pseudoephedrine

3.84

0.64

Acetaminophen

3.94

0.66

Benzylpiperazine

4.28

0.71

Methylephedrine

4.94

0.73

Amphetamine

4.98

0.83

3,4-MDA

5.76

0.96

Methamphetamine

6.00

1.00

Caffeine

6.04

1.01

3,4-MDMA

6.77

1.13

Dimethylamphetamine

6.78

1.13

Phentermine

7.19

1.20

4-Methoxymethamphetamine

7.44

1.24

N,N-Dimethyl-3,4-MDA

7.64

1.27

Ethylamphetamine

8.13

1.36

3,4-MDEA

9.32

1.55

Ketamine

10.70

1.78

N-Hydroxy-3,4-MDA

10.93

1.82

MBDB

11.96

1.99

* * * * *

Table 4. Mass Ion Abundances and % Relative Intensity of Mass Ion Abundances at 150 V for compounds examined.

Compound

 Ion#1(m/z)

 Ion#2(m/z)

 Ion#3(m/z)

 Ion#4(m/z)

 Ion#5(m/z)

Niacinamide

123(100%)

124(7.4%)

80 (3.3%)

50(2.4%)

78(1.3%)

Acetaminophen

152(100%)

110(18.2%)

102(14.7%)

153(9.3)

174(3.3%)

Phenethylamine

105(100%)

79(5.7%)

103(4.6%)

 

 

Methylephedrine

180(100%)

162(21.0%)

181(12.6%)

135(5.9%)

163(2.5%)

Phenylpropanolamine

134(100%)

135(13.6%)

117(7.1%)

152(6.7%)

 

Ephedrine

148(100%)

166(33%)

149(10.9%)

135(4.3%)

167(4.0%)

Pseudoephedrine

148(100%)

166(13.9%)

149(11.9%)

133(3.5%)

167(1.8%)

Benzylpiperazine

177(100%)

178(12.2%)

91(4.9%)

85(1.2%)

 

Amphetamine

91(100%)

119(59.7%)

136(9.0%)

120(6.3%)

65(0.9%)

Caffeine

195(100%)

196(10.3%)

138(4.3%)

 

 

3,4-MDA

163(100%)

164(11.4%)

180(9.1%)

135(7.8%)

133(6.9%)

Methamphetamine

150(100%)

91(82.8%)

119(70.5%)

151(11.7%)

92(6.8%)

3,4-MDMA

163(100%)

194(73.3)

164(11.0%)

195(9.5%)

135(6.7%)

Dimethylamphetamine

164(100%)

119(15.9%)

91(15.4%)

165(13.2%)

92(1.2%)

Phentermine

133(100%)

91(63.4%)

150(11.9%)

134(10.9%)

105(7.9%)

N,N-Dimethyl-3,4-MDA

208(100%)

163(35.3%)

209(13.6%)

164(4.0%)

135(2.6%)

4-Methoxymethamphetamine

149(100%)

180(37.6%)

121(14.1%)

150(11.6%)

181(4.6%)

Ethylamphetamine

164(100%)

91(32.8%)

119(32.7)

165(13.0%)

120(3.2%)

3,4-MDEA

208(100%)

163(70.4%)

209(14.1%)

135(5.1%)

133(4.7%)

Ketamine

238(100%)

240(32.3%)

239(14.5%)

207(12.7%)

179(6.9%)

MBDB

208(100%)

135(50.1%)

177(40.3%)

209(14.3%)

147(6.0%)

N-Hydroxy-3,4-MDA

163(100%)

196(17.8%)

164(10.9%)

105(7.1%)

135(6.3%)

* * * * *

Table 5. Fragmentor Voltage Optimization of Mass Ions for Compounds Examined.

Compound

 Ion#1 (Voltage)

 Ion#2

 Ion#3

 Ion#4

 Ion#5

Niacinamide

123(120V)

124 (120)

80 (200)

50 (200)

78 (200)

Acetaminophen

152(100)

110(180)

93(200)

153(120)

174(3.3%)

Phenethylamine

122 (70)

105(120)

79(180)

 

 

Methylephedrine

180(100)

162(180)

181(100)

135(160)

163(180)

Phenylpropanolamine

134(140)

135(140)

117(180)

152(100)

 

Ephedrine

148(160)

166(100)

149(160)

135(140)

167(100)

Pseudoephedrine

148(160)

166(100)

149(160)

133(200)

167(100)

Benzylpiperazine

177(100)

178(100)

91(200)

85(180)

 

Amphetamine

91(180)

119(140)

136(100)

120(140)

65(220)

Caffeine

195(140)

196(140)

138(200)

 

 

3,4-MDA

163(140)

164(140)

180(120)

135(200)

133(180)

Methamphetamine

150(100)

91(200)

119(140)

151(100)

92(180)

3,4-MDMA

163(160)

194(100)

164(160)

195(100)

135(200)

Dimethylamphetamine

164(100)

119(160)

91(200)

165(100)

92(200)

Phentermine

133(140)

91(180)

150(100)

134(140)

105(180)

N,N-Dimethyl-3,4-MDA

208(120)

163(180)

209(120)

164(180)

135(220)

4-Methoxymethamphetamine

149(160)

180(100)

121(200)

150(160)

181(100)

Ethylamphetamine

164(100)

91(200)

119(140)

165(100)

120(140)

3,4-MDEA

208(100)

163(180)

209(100)

135(220)

133(180)

Ketamine

238(120)

240(100)

239(100)

207(180)

179(180)

MBDB

208(100)

135(200)

177(160)

209(100)

147(180)

N-Hydroxy-3,4-MDA

163(160)

196(100)

164(140)

105(220)

135(200)

* * * * *


Figure 1. Total Ion Chromatogram of 5 Components Mixture of 3,4-MDA Analogs. (a) 3,4-MDA, (b) 3,4-MDMA, (c) N,N-Dimethyl-3,4-MDA, (d) 3,4-MDEA, (e) MBDB.

Figure 1. Total Ion Chromatogram of 5 Components Mixture of 3,4-MDA Analogs. (a) 3,4-MDA, (b) 3,4-MDMA, (c) N,N-Dimethyl-3,4-MDA, (d) 3,4-MDEA, (e) MBDB.

* * * * *


Figure 2. Total Ion Chromatogram of 12 Component Drug Mixture. (a) Niacinamide, (b) Acetaminophen, (c) Ephedrine, (d) Benzylpiperazine, (e) Amphetamine, (f) 3,4-MDA, (g) Methamphetamine, (h) 3,4-MDMA, (i) Phentermine, (j) 3,4-MDEA, (k) Ketamine, (l) MBDB.

Figure 2. Total Ion Chromatogram of 12 Component Drug Mixture. (a) Niacinamide, (b) Acetaminophen, (c) Ephedrine, (d) Benzylpiperazine, (e) Amphetamine, (f) 3,4-MDA, (g) Methamphetamine, (h) 3,4-MDMA, (i) Phentermine, (j) 3,4-MDEA, (k) Ketamine, (l) MBDB.

* * * * *


Figure 3. Total Ion Chromatogram of Mixture of 7 amines of interest. (a) Ephedrine, (b) Amphetamine, (c) Methamphetamine, (d) Dimethylamphetamine, (e) Phentermine, (F) 4-Methoxymethamphetamine, (g) Ethylamphetamine.

* * * * *


Figure 4. ESI Mass Spectra of Methamphetamine (top) and Phentermine (bottom).

Figure 4. ESI Mass Spectra of Methamphetamine (top) and Phentermine (bottom).

* * * * *


Figure 5. ESI Mass Spectra of 3,4-MDA (top) and 3,4-MDMA (bottom).

Figure 5. ESI Mass Spectra of 3,4-MDA (top) and 3,4-MDMA (bottom).

* * * * *


Figure 6. ESI Mass Spectra of Ethylamphetamine (top), Amphetamine (middle), and Dimethylamphetamine (bottom).

Figure 6. ESI Mass Spectra of Ethylamphetamine (top), Amphetamine (middle), and Dimethylamphetamine (bottom).

* * * * *


Figure 7. ESI Mass Spectra of 3,4-MDEA (top), MBDB (middle), and N,N-Dimethyl-3,4-MDA (bottom).

Figure 7. ESI Mass Spectra of 3,4-MDEA (top), MBDB (middle), and N,N-Dimethyl-3,4-MDA (bottom).

* * * * *


Figure 8. ESI Mass Spectra of N-Hydroxy-3,4-MDA (top), 4-Methoxymethamphetamine (middle), and Ketamine (bottom).

Figure 8. ESI Mass Spectra of N-Hydroxy-3,4-MDA (top), 4-Methoxymethamphetamine (middle), and Ketamine (bottom).

* * * * *


Figure 9. ESI Mass Spectra of Pseudoephedrine (top), Ephedrine (middle), and Methylephedrine (bottom).

Figure 9. ESI Mass Spectra of Pseudoephedrine (top), Ephedrine (middle), and Methylephedrine (bottom).

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Figure 10. ESI Mass Spectra of Phenylpropanolamine (top) and Phenethyamine (bottom).

Figure 10. ESI Mass Spectra of Phenylpropanolamine (top) and Phenethyamine (bottom).

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Figure 11. Collision Induced Dissociation of 3,4-MDMA.

Figure 11. Collision Induced Dissociation of 3,4-MDMA.

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Figure 12. Flow Injection Analysis of 3,4-MDMA Monitored at m/z 194. Fragmentor Ramped from 100 V - 240 V at 20 V Increments.

Figure 12. Flow Injection Analysis of 3,4-MDMA Monitored at m/z 194. Fragmentor Ramped from 100 V - 240 V at 20 V Increments.

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Figure 13 . Total Ion Chromatogram of Illicit Tablets Containing (A) Ephedrine, (B) Caffeine, (C) Methamphetamine, and (d) 3,4-MDMA, on a Hydro-RP Column.

Figure 13 . Total Ion Chromatogram of Illicit Tablets Containing (A) Ephedrine, (B) Caffeine, (C) Methamphetamine, and (d) 3,4-MDMA, on a Hydro-RP Column.

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Figure 14. Total Ion Chromatogram of Illicit Powder Containing (A) Amphetamine, (B) Methamphetamine, and (C) Caffeine, on a Polar-RP Column.

Figure 14. Total Ion Chromatogram of Illicit Powder Containing (A) Amphetamine, (B) Methamphetamine, and (C) Caffeine, on a Polar-RP Column.

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Figure 15. Fragmentor Voltage Optimization for Compounds of Interest.

Figure 15. Fragmentor Voltage Optimization for Compounds of Interest.

Identification of Phenethylamines and Methylenedioxyamphetamines
Using Liquid Chromatography Atmospheric Pressure
Electrospray Ionization Mass Spectrometry

Identification of Phenethylamines and Methylenedioxyamphetamines Using Liquid Chromatography Atmospheric Pressure Electrospray Ionization Mass Spectrometry Adrian S. Krawczeniuk U.S. Department of Justice Drug Enforcement Administration Northeast Laboratory 99 - 10th Avenue, Suite 721 New York, NY 1 ...»See Ya