Methods for impurity profiling of heroin and cocaine

Methods for impurity profiling

43

Rationale for use: No derivatization and relatively simple sample preparation. Good

retrospective data searches via comparison of the ratios of cis-cinnamoylcocaine and

trans-cinnamoylcocaine to cocaine.

Outcome: Sample comparisons for discrimination and evaluation of samples for case-

to-case evidential purposes (linkage determinations). Should be used to substantiate

results of the methods used for major components.

Method D4:

GC or GC/MS method, without derivatization

Source: M. LeBelle and others, “Comparison of illicit cocaine by determination of minor

components”,  Journal of Forensic Sciences, vol. 36, No. 4 (1991), pp. 1102-1120.

Method D4.1:

GC/MS method, without derivatization

Operating conditions (GC/MS method):

Detector:

Finnigan Mat Model 800 Ion Trap Detector, electron

impact mode 40 to 500 amu, 1 sec scan cycle

Column:

DB-5 or equivalent, 15 m x 0.25 mm x 0.25 µm

Carrier gas:

Helium at 55 cm/sec at 160° C oven temperature

Injection 

technique:

1 µl; split 25:1

Temperatures:

Injector: 275° C

Oven: 160° C for 3 min, 3° C/min to 255° C for 1 min,

20° C/min to 295° C, final hold for 1 min

Sample preparation: To a 400 mg uncut sample add 5 ml of 0.5 M sulphuric acid

and 5 ml of toluene and mix thoroughly. Centrifuge to separate phases, aspirate as

much toluene as possible, add 5 ml of 0.5 M H

2

SO

4

, mix, centrifuge and aspirate the

toluene layer. Combine the toluene extracts and evaporate under a stream of nitrogen at

40° C. Immediately dissolve the residue in 50 µl of ethyl acetate. Inject, in duplicate.*

Method D4.2:

GC method, without derivatization

Modification of method D4.1 

Operating conditions (GC method):

Detector:

FID, at 30 ml/min hydrogen and 400 ml/min air

Column:

DB-5 or equivalent, 15 m x 0.25 mm x 0.25 µm

Carrier gas:

Helium at 40 cm/sec at 160° C oven temperature; 

head pressure 85 kPa 

*If a sample cannot be analysed immediately, evaporate it almost to dryness and store the

resulting sample in a refrigerator (5° C) for future analysis.

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44

Methods for impurity profiling of heroin and cocaine

3.

Residual solvent analysis 

Injection 

technique:

1 µl; split 25:1

Make-up gas:

Nitrogen at 30-40 ml/min

Temperatures:

Injector: 275° C

Detector: 275° C

Oven: 160° C for 3 min, 3° C/min to 255° C for 1 min,

20° C/min to 295° C, hold for 1 min

Internal standard: None 

Sample preparation: See method D4.1 above

Rationale for use: Provides a peak rich impurity profile of minor and trace impurities

many of which are unknown. No derivatization and relatively simple sample prepa-

ration. Good retrospective data searches via comparison of the ratios of cis-cinnamoyl-

cocaine and trans-cinnamoylcocaine to cocaine. 

Outcome: Sample comparisons for discrimination and evaluation of samples for case-

to-case evidential purposes (linkage determinations). Should be used to substantiate

results of the methods used for major components.

Method D5: Thermal desorption-GC

Source: J. Cartier, O. Guéniat and M. D. Cole, “Headspace analysis of solvents in

cocaine and heroin samples”, Science and Justice, vol. 37, No. 3 (1997), pp. 175-181.

Method is identical to that used for heroin (see method B5 in subsection 4, above).

For cocaine, it provides for the detection of 16 solvents, at detection limits of 2-15 ppm

for 250-300 mg powder samples.

Method D6:

Static headspace, GC/MS

Source: D. R. Morello and R. P. Meyers, “Qualitative and quantitative determination

of residual solvents in illicit cocaine HCl and heroin HCl”, Journal of Forensic

Sciences, vol. 40, No. 6 (1995), pp. 957-963.

The method is identical to that used for heroin (see method B6 in subsection 4, above),

except for sample preparation, where a sample weight of 100 mg of cocaine equiva-

lent is used.

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Methods for impurity profiling

45

4.

Additional methods

Method D7:

GC-ECD method for unadulterated samples

Source: J. M. Moore and D. A. Cooper, “The application of capillary gas chromatog-

raphy-electron capture detection in the comparative analyses of illicit cocaine samples”,

Journal of Forensic Sciences, vol. 38, No. 6 (1993), pp. 1286-1304.

Rationale for use: This GC-ECD method provides for the detection and quantification

of 6- and 7-exo and 6- and 7-endohydroxycocaines along with manufacturing by-

products of norcocaine and benzoylnorecgonine methyl ester. The method is designed

for unadulterated samples.

Outcome: Aids in the evaluation of samples for case-to-case evidential purposes (link-

age determinations). Provides additional information required to confirm links between

samples, that is, the method should be used in conjunction with a major component

analysis.

Method D8:

GC/MS method for unadulterated samples

Sources: J. F. Casale and J. M. Moore, “Lesser alkaloids of cocaine-bearing

plants: III. 2-Carbomethoxy-3-oxo substituted tropane esters; detection and gas-

chromatographic-mass spectrometric characterization of new minor alkaloids found in

South American Erythroxylum coca var. coca”,  Journal of Chromatography A,

vol. 756, Nos. 1-2 (1996), pp. 185-192; J. F. Casale, J. M. Moore and N. G. Odeneal,

“Comparative determination of 2-carbomethoxy-3-alkyloxy- and heteroaroyloxy-

substituted tropanes in illicit South American cocaine using capillary gas chromatog-

raphy-single ion monitoring”, Journal of Forensic Sciences, vol. 43, No. 1 (1998),

pp. 125-132.

Rationale for use: This GC-MS method provides for the detection and quantification

of 3-oxo-heteroaryl and 3-oxo-hydrocarbon substituted 2-carbomethoxytropanes.

Detection is accomplished in the selected ion monitoring mode. The method is

designed for unadulterated samples.

Outcome: Aids in the evaluation of samples for case-to-case evidential purposes (link-

age determinations). Provides additional information required to confirm links between

samples, that is, the method should be used in conjunction with a major component

analysis.

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