Methods for impurity profiling of heroin and cocaine

36

Methods for impurity profiling of heroin and cocaine

1.

Methods for the determination of major components

Method C1:

GC method, with derivatization 

(Chromatographic Impurity Signature Profile Analysis (CISPA))

Source: J. F. Casale and R. W. Waggoner, Jr. “A chromatographic impurity signature

profile analysis for cocaine using capillary gas chromatography”, Journal of Forensic

Sciences, vol. 36, No. 5 (1991), pp. 1312-1330.

Operating conditions:

Detector:

FID

Column:

DB-1701, or equivalent, 30 m x 0.25 mm x 0.25 µm

Carrier gas:

Helium at 30 cm/sec

Injection 

technique:

5 µl; split 50:1

Make-up gas:

Nitrogen at 30 ml/min

Temperatures:

Injector: 230° C

Detector: 280° C

Oven: 180° C for 1 min, to 200° C at 4° C/min, to 275° C

at 6° C/min, final hold of 11.5 min

Internal standard: p-fluorococaine at a concentration of 175 µg/ml in chloroform

Sample preparation: Accurately weigh out a sample of about 4-5 mg of unadultera-

ted cocaine base or hydrochloride into a small vial. Add 200 µl of internal standard

and 200 µl of MSTFA. Cap the vial and heat it at 80° C for 15 min. Cool to room

temperature before analysis.

Reference chromatograms: See annex III, figure V and table 4.

Rationale for use: Nearly complete picture of major components, including adulter-

ants and cutting agents. The authors noted that the method was designed for the analy-

sis of unadulterated samples. However, others have also found the method to be

suitable for many cut samples.* Derivatization allows for the facile detection of sug-

ars and avoids decomposition of the coca alkaloids in the GC injection port. This

method requires the synthesis of the internal standard, p-fluorococaine; however, this

internal standard is easily made from commercially available precursors. The use of

a structurally related internal standard significantly enhances precision and repro-

ducibility. The authors successfully apply a neural network pattern recognition pro-

gramme for retrospective database searches.

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

to-case evidential purposes. Additional information is required to confirm links

between samples or to assign source regions, that is, the method should be used as

one part within a broader analysis scheme.

*The method can identify most of the common adulterants and diluents and some of the trace

components such as tropacocaine, norcocaine and N-formylcocaine (personal communication from

Olivier Guéniat, Police de sûreté, Neuchâtel, Switzerland, 2005).

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Methods for impurity profiling

37

Method C2:

GC method, with derivatization

Source: Olivier Guéniat, Police de sûreté, Neuchâtel, Switzerland.

This method is a modification of the previously described method C1.

Operating conditions: 

Detector:

FID at 45 ml/min hydrogen and 450 ml/min air

Column:

DB-1, or equivalent, 30 m x 0.25 mm x 0.25 µm*

Carrier gas:

Helium at 1 ml/min

Injection:

3 µl; split 50:1

Temperatures:

Injector: 230° C

Detector: 320° C

Oven: 180° C, hold for 1 min, then to 275° C at 4° C/min,

hold for 5.25 min

Internal standard: Heneicosane at a concentration of 1 mg/ml in chloroform:pyridine

(5:1)

Sample preparation: Weigh approximately 8 mg of cocaine sample. Add 500 µl of

the internal standard and 100 µl of MSTFA. Cap the vial and heat it at 80° C for

30 min. After cooling the vial to room temperature for one hour, inject the solution.

Rationale for use: Nearly complete picture of major components, including adulter-

ants and cutting agents. Derivatization allows for the facile detection of sugars and

avoids decomposition of the coca alkaloids in the GC injection port. Uses a commer-

cially available internal standard. 

Outcome: Sample comparisons for discrimination and evaluation of samples for 

case-to-case evidential purposes. Additional information is required to confirm links

between samples or to assign source regions, that is, the method should be used as

one part within a broader analysis scheme.

Method C3:

GC method, without derivatization

Source: James Wong, Bureau of Drug Analysis Services, Health Canada, Western

Region Health Protection Branch, Burnaby, British Columbia, Canada.

*A DB-5 column has also been found to be suitable (personal communication from Jana

Skopec, 2005).

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38

Methods for impurity profiling of heroin and cocaine

Operating conditions:

Detector:

FID 

Column:

DB-5 or equivalent, 25 m x 0.32 mm x 0.50 µm

Carrier gas:

Helium 

Injection size:

1 µl; split 25:1

Temperatures:

Injector: 250° C

Detector: 310° C

Oven: 200° C, hold for 0.5 min, 20° C/min to 295° C, final

hold 3 min

Internal standard: None; normalize by ratio of area counts for cis- and trans-

cinnamoylcocaine relative to cocaine. 

Sample preparation: Dissolve 15-20 mg of the sample in 10 ml methanol.

Rationale for use: Simple sample preparation and a less than nine-minute GC analysis

provides for excellent sample throughput. Data reduction only relies on two alkaloidal

ratios (i.e. the area counts of cis- and trans-cinnamoylcocaine to cocaine).

Outcome: Sample comparisons for discrimination and evaluation of samples for 

case-to-case evidential purposes. Additional information is required to confirm links

between samples or to assign source regions, that is, the method should be used as

one part within a broader analysis scheme.

Method C4:

GC method, without derivatization, 

nitrogen phosphorous detector (NPD)

Sources: K. E. Janzen, L. Walter and A. R. Fernando, “Comparison analysis of illi-

cit cocaine samples”, Journal of Forensic Sciences, vol. 37, No. 2 (1992), pp. 436-445;

see also K. E. Janzen, “Cross-matching of cocaine samples: a case study”, Canadian

Society of Forensic Science Journal, vol. 20, 1987, pp. 77-81; K. E. Janzen, A. R.

Fernando and L. Walter, “A database for comparison analysis of illicit cocaine sam-

ples”,  Forensic Science International, vol. 69, No. 1 (1994), pp. 23-29.

Operating conditions:

Detector:

NPD, at 3 ml/min hydrogen and 80 ml/min air

Column:

HP-1, DB-1 or equivalent, 12.5 m x 0.2 mm x 0.5 µm

Carrier gas:

Helium at 1.5 ml/min 

Make-up gas:

Helium at 30 ml/min

Injection 

technique:

1 µl; split 50:1

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