Methods for impurity profiling of heroin and cocaine

Methods for impurity profiling

19

Rationale for use: The outstanding virtues of the method are simple sample prepara-

tion (i.e. no extraction or derivatization), very quick instrumental analysis (< 10 min-

utes) and therefore fast sample throughput. Although the method is not the most

sensitive, it has relatively good resolution and discrimination power and a broad range

of compounds can be detected. The method detects major opiate or opiate-related com-

pounds as well as many cutting agents. Sugars are not detected and a co-elution issue

is known to exist between diazepam and morphine. The separation of O6MAM,

acetylthebaol and acetylcodeine can, in some instances, be problematic. 

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

to-case evidential purposes (linkage determinations). Additional information is required

to confirm links between samples, that is, the method should be used as one part with-

in a broader analysis scheme.

Method A3:

GC method, without derivatization

Source: Adrian V. Kemmenoe, Forensic Science Service, Birmingham Laboratory,

Birmingham, United Kingdom.

Sample type: Major components: cut and uncut samples.

Operating conditions:

Detector:

FID at 35 ml/min hydrogen, air at 350 ml/min

Column:

HP1, 25 m x 0.2 mm x 0.33 µm

Carrier gas: 

Helium (0.9 ml/min to 1.5 ml/min at 0.1 ml/min, final hold

for 5 min)

Injection:

1 µl; split 100:1 

Make-up gas:

Nitrogen at 30 ml/min

Temperatures:

Injector:

280° C

Detector:

300° C

Oven:

220° C to 300° C at 10° C/min, final hold for

3 min

Internal standard: n-Tetracosane at 0.5 mg/ml (±0.0001 mg/ml) in chloroform:

ethanol:isopropyl alcohol (8:1:1)

Calibration standard preparation: Prepare two calibration standards for each target

analyte, with one standard solution prepared at the highest expected concentration and

the other at a lower concentration. For the high concentration heroin HCl, dissolve

20 mg standard into 5 ml internal standard solution, and for the lower concentration

standard, dissolve 10 mg standard in 5 ml of internal standard solution. 

Sample preparation: Dissolve sufficient sample in 5 ml of internal standard solution

to give a final total heroin content (calculated as the hydrochloride salt) of 10-20 mg

(2-4 mg/ml).

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20

Methods for impurity profiling of heroin and cocaine

Rationale for use: As in the previous method, the outstanding virtues of the method

are simple sample preparation (i.e. no extraction or derivatization), quick instrumen-

tal analysis (ca. 11 minutes) and therefore fast sample throughput. The method is rea-

sonably sensitive; given the use of the non-polar methyl silicone column phase, it has

relatively good resolution and discrimination power; and a broad range of compounds

can be detected. The method detects major opiate or opiate-related compounds as well

as many cutting agents. Sugars are not detected and a co-elution issue is known to

exist between diazepam and morphine. The separation of O6MAM, acetylthebaol and

acetylcodeine can, in some instances, be problematic. 

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

to-case evidential purposes (linkage determinations). Additional information is required

to confirm links between samples, that is, the method should be used as one part with-

in a broader analysis scheme.

Method A4:

GC method, with derivatization

Sources: Modified from M. Gloger and H. Neumann, “Analysis of heroin samples by

capillary gas chromatography: comparison of glass capillary column and packed col-

umn”, Forensic Science International, vol. 22, No. 1 (1983), pp. 63-74; H. Neumann,

“Vergleichende Heroinanalyse mit der Kapillar-GC: Bestimmung charakteristischer

Größen”,  Toxichem+Krimtech, vol. 59, Nos. 3-4 (1992), pp. 121-124.

Sample type: Major components: cut and uncut samples.

Operating conditions:

Detector:

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

Column:

HP-1, DB-1 or equivalent, 30 m x 0.32 mm x 0.25 µm

Carrier gas:

Helium at 61 cm/sec, measured at 150° C oven temperature

Injection:

1 µl; split, 15:1

Make-up gas:

Argon or nitrogen at 25 ml/min

Temperatures:

Injector: 250° C 

Detector: 310° C 

Oven: 150° C to 300° C at 9° C/min, hold for 2.4 min

Internal standard: n-Tetracosane (see sample preparation)

Sample preparation: Weigh accurately approximately 5 mg of sample together with

1 mg of n-tetracosane as internal standard. Dissolve the mixture in 1 ml of chloro-

form and 200 µl of pyridine. Silylation is performed with 150 µl of N-methyl-N-

trimethylsilyltrifluoroacetamide (MSTFA). Heat for 10 minutes at 70° C and then let

stand one hour at room temperature. 

Reference chromatograms: See annex III, figure I.

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Methods for impurity profiling

21

Rationale for use: This is a robust method* that can be modified in many ways. As

a result of the derivatization step the method provides a nearly complete picture of

the major organic components to include most adulterants and many cutting agents.

The combination of a derivatization step coupled with the use of a fused silica non-

polar capillary column results in superior resolution and excellent discrimination power

and also avoids problems associated with transacetylation. Mono- and disaccharides

are detected with high sensitivity and high chromatographic resolution. Known co-

elution issues are present with diazepam, quinine and phenylbutazone with n-tetra-

cosane and heroin, respectively. A modification using a 30 m x 0.25 mm x 0.25 µm

DB-1 with H

2

as the carrier gas (60-70 cm/sec constant velocity) allows complete sep-

aration of those compounds; however, chloroquine and heroin were found to co-elute

in this system.

Outcome: Indication of general source region (South-East Asia, South-West Asia,

Mexico, South America). Sample comparisons for discrimination and evaluation of

samples for case-to-case evidential purposes (linkage determinations). Additional infor-

mation 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 A5:

GC method, with derivatization 

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

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

Sample type: Major components: cut and uncut samples.

Operating conditions:

Detector:

FID

Column:

DB-5 or equivalent, 25 m x 0.32 mm x 0.52 µm

Carrier gas:

Helium 

Injection:

2 µl; split 25:1

Temperatures:

Injector: 250° C

Detector: 310° C

Oven: 200° C for 0.5 min, 20° C/min to 280° C, hold for

17 min

Internal standard: None; normalize by ratios of the area counts for O

3

-benzoyl-O6MAM

to heroin and acetylcodeine to heroin.

Derivatization solution: 10 µl benzoyl chloride/ml chloroform

Sample preparation: Dissolve 15-20 mg of the sample in 10 ml 0.1N HCl. Accurately

pipette 1 ml of this solution to a 15-ml round-bottomed centrifuge or test tube, add

*Note that this method is the same as the GC method recommended in the United Nations

manual  Recommended Methods for Testing Opium, Morphine and Heroin [6].

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