ASTM_E_1968_-_11.pdf

Designation:E196811Standard Guide forMicrocrystal Testing in Forensic Analysis of Cocaine1This standard is issued under the fixed designation E1968;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONMicrocrystal tests are primarily chemical-precipitation tests in which a light microscope is used toobserve and distinguish the different types of crystals formed.These tests require skill and expertiseon the part of the analyst that can be gained adequately only through appropriate training andexperience in their use.These tests should not be attempted by those who are unfamiliar with themfor use in the analysis of cocaine.1.Scope1.1 This guide describes some standard procedures appli-cable to the analysis of cocaine using multiple microcrystaltests(1-5).21.2 These procedures are applicable to cocaine,which ispresent in solid dosage form or an injectable liquid form.Theyare not typically applicable to the analysis of cocaine inbiological samples.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard cannot replace knowledge,skill,or abilityacquired through appropriate education,training,and experi-ence and should be used in conjunction with sound profes-sional judgment.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3E1459 Guide for Physical Evidence Labeling and RelatedDocumentationE1492 Practice for Receiving,Documenting,Storing,andRetrieving Evidence in a Forensic Science LaboratoryE1732 Terminology Relating to Forensic ScienceE2329 Practice for Identification of Seized DrugsE2548 Guide for Sampling Seized Drugs for Qualitative andQuantitative Analysis3.Terminology3.1 For definitions of terms used in this standard,refer toTerminology E1732.3.2 Definitions of Terms Specific to This Standard:3.2.1 aggregation,nthe collecting of units or parts into amass or whole.3.2.2 birefringence,nproperty of some crystals,havingmore than one refractive index;this property will result ininterference colors,which are viewed through a polarized lightmicroscope.3.2.3 cocaine,neither d-or l-cocaine;it should be notedthat l-cocaine is the naturally occurring isomer found in thecoca plant.3.2.4 dendritic,adjmultibrachiate or branching crystals,growing in a tree-like manner;each branch of the crystal iscontiguous structurally.3.2.5 habit,nthe external morphology of the crystal.3.2.6 microdrop,na small drop of liquid that would fit onthe end of a standard size,flattened toothpick;the approximatevolume of this drop would be 10 to 25 L.3.2.7 needles(acicular),nlong,thin crystals with pointedends.4.Summary of the Technique4.1 A small sample of the material containing the suspectedcocaine is dissolved in a dilute acid and the appropriate1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved March 1,2011.Published April 2011.Originallyapproved in 1998.Last previous edition approved in 2003 as E1968 98(2003).DOI:10.1520/E1968-11.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 precipitating reagent is added.The crystals that are formed areobserved and distinguished utilizing a light microscope.5.Significance and Use5.1 This technique produces a chemical-precipitation reac-tion between cocaine and the precipitating reagent.The habitand the aggregation of the crystals formed may be used todistinguish cocaine from other drugs(6).5.2 This technique can be utilized on cocaine present ineither the salt or free base form.5.3 This technique does not distinguish between the salt andfree base forms.6.Interferences6.1 Diluents/AdulterantsDiluents/adulterants,such as li-docaine or benzocaine,present in combination with cocaine inthe sample to be tested may inhibit crystal formation or mayresult in crystals that are distorted or otherwise renderedunidentifiable.In these instances,it will be necessary toseparate the cocaine from the diluents/adulterants or to useother testing methods to analyze for cocaine.7.Apparatus7.1 Standard Light Microscope