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

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 adulterants
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 commercially
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.
*A DB-5 column has also been found to be suitable (personal communication from Jana
Skopec, 2005).
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.