methods for impurity profiling of heroin and cocaine - United Nations ...

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 nonpolar
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 coelution
issues are present with diazepam, quinine and phenylbutazone with n-tetracosane
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 separation
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 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.
*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].
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