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

Methods for impurity profiling 19
Rationale for use: The outstanding virtues of the method are simple sample preparation
(i.e. no extraction or derivatization), very quick instrumental analysis (< 10 minutes)
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 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 caseto-case
evidential purposes (linkage determinations). Additional information is required
to confirm links between samples, that is, the method should be used as one part within
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).