ASTM E1968-19 describes procedures applicable to the analysis of cocaine using multiple microcrystal tests.
This technique involves a chemical-precipitation reaction between cocaine and the precipitating reagent. The habit and the aggregation of the crystals formed could be used to distinguish cocaine from other drugs (6).
This technique can be utilized on cocaine present in either the salt or free base form.
This technique does not distinguish between the salt and free base forms.
10. Performance Verification
10.1 Prior to casework, the reagents used for these microcrystal tests shall be tested for reliability using a cocaine standard and negative controls following the prescribed procedure. Only when it is determined that the reagents are producing the expected response could the reagents be used in the testing procedure.
10.2 The microscope should be inspected, adjusted, and aligned to ensure it is in proper working order. This can be confirmed during the testing of the cocaine standard. Perform the analysis of unknown samples and standards under the same microscope operating procedures.
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