[Study on the linked samples of methamphetamine identified by the impurity profile].

Objective: To compare and classify the samples of MA crystals by using impurity profile to offer methods for identification of linked samples.

Methods: 50 mg samples of MA were dissolved in 1 ml of buffer solution (pH 7.0, four parts of 0.1 mol/L phosphate buffer, and one part of 10% Na2CO3), impurities were extracted with 0.5 ml of ethyl acetate containing four internal standards (n-decane, n-pentadecane, n-eicosane and n-octacosane) and analyzed by gas chromatography with a flame ionization detector on a DB-5 capillary column (30 m x 0.32 mm i.d. x 1.0 microm). Seventeen characteristic peaks on chromatograms were selected for the comparison and classification of samples, and the data were evaluated by the Euclidean distance of the relative peak areas after logarithmic transformation.

Results: Eight different batches of MA (six samples from each batch) to be seized by the Beijing Public Security Bureau (BPSB) in 2006-2007 were analyzed. The results indicated that the samples from the same batch were successfully classified into one group.

Conclusion: The methods could be very useful for identifying the linked samples and could provide technique foundation for MA drug criminal inspection.