1、Designation: E1969 11Standard Guide forMicrocrystal Testing in Forensic Analysis ofMethamphetamine and Amphetamine1This standard is issued under the fixed designation E1969; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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 dis
3、tinguish 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 analy
4、sis of methamphetamine or amphetamine.1. Scope1.1 This guide describes some standard procedures appli-cable to the analysis of methamphetamine and amphetamineusing microcrystal tests (1-6).21.2 These procedures are applicable to methamphetamineand amphetamine, which are present in solid dosage form
5、or aninjectable liquid form. These procedures are not typicallyapplicable to the analysis of methamphetamine and amphet-amine in biological 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 rep
6、lace 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
7、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, Document
8、ing, 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 Qualitativeand Quantitative Analysis3. Terminology3.1 For definitions of terms used in this st
9、andard, 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 refraction index; this property will result ininterference colors, which
10、are viewed through a polarized lightmicroscope.3.2.3 blades, nbroad, flat, elongated crystals.3.2.4 grains, nthick tablets having nearly equal width,breadth and thickness.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 stand
11、ard size, flattened toothpick; the approximatevolume of this drop would be 10 to 25 L.3.2.7 needles (acicular), nlong, thin crystals with pointedends.3.2.8 plates, nblades with nearly equal length and breadthand of a thickness substantially less than the width.3.2.9 rods, nlong, thin crystals with s
12、quared off ends.3.2.10 tablets, nplates with appreciable thickness but lessthan the length or breadth.1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility on Subcommittee E30.01 on Criminalistics.Current edition approved March 1, 2011. Publ
13、ished April 2011. Originallyapproved in 1998. Last previous edition approved in 2006 as E1969 06. DOI:10.1520/E1969-11.2The 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 Cu
14、stomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of the Technique4.1 A
15、small sample of the material containing the suspectedmethamphetamine or amphetamine is dissolved in an appro-priate acid and the appropriate precipitating reagent is added.The crystals that are formed are observed and distinguishedutilizing a light microscope.4.2 If the proper formation of crystals
16、is inhibited by thepresence of diluents, a purification of the sample based on thevolatility of methamphetamine and amphetamine may beperformed.5. Significance and Use5.1 This technique produces a chemical-precipitation reac-tion between methamphetamine or amphetamine and the pre-cipitating reagent.
17、 The habit and the aggregation of the crystalsformed may be used to distinguish methamphetamine andamphetamine from other drugs.6. Interferences6.1 Diluents/AdulterantsDiluents/adulterants present incombination with methamphetamine or amphetamine in thesample to be tested may inhibit crystal formati
18、on or result incrystals that are distorted or otherwise rendered unidentifiable.In these instances, it will be necessary to separate the meth-amphetamine or amphetamine from the diluents or to use othertesting methods to analyze the methamphetamine or amphet-amine.7. Apparatus7.1 A standard light mi
19、croscope capable of varying magni-fications including 1003 is needed for viewing the crystals. Apolarized light attachment is not essential, but is desirable,because the heavy metal crystals of methamphetamine andamphetamine are birefringent.8. Reagents and Materials8.1 10 % Solution of Hydrochloric
20、 Acid.8.2 Concentrated Phosphoric Acid.8.3 1.0 N to 10.0 N Sodium Hydroxide.8.4 Gold Chloride (HAuCI4) Solution, approximately 5 %,in reagent grade water. Gold chloride in phosphoric acid also issuitable.8.5 Platinum Chloride (H2PtC16) Solution, approximately5 %, in reagent grade water. Platinum chl
21、oride in phosphoricacid also is suitable.8.6 Amphetamine Standard.8.7 Methamphetamine Standard.9. Sampling, Test Specimens, and Text Units9.1 The general handling and tracking of samples shouldmeet or exceed the requirements of Practice E1492 and GuidesE1459 and E2548.10. Calibration and Standardiza
22、tion10.1 The reagents utilized for these microcrystal tests are tobe tested for reliability using amphetamine and methamphet-amine standards and negative controls following the prescribedprocedure. Only when it is determined that the reagents areproducing the expected response may the reagents be us
23、ed inthe testing procedure.11. Procedure11.1 Gold Chloride:11.1.1 Place a small sample, a few particles of powder, lessthan 1 mg, of the suspected methamphetamine or amphetamineon a microscope slide.11.1.2 Dissolve the sample in a few microdrops of 10 %hydrochloride acid or concentrated phosphoric a
24、cid.NOTE 1The crystals tend to precipitate faster from the phosphoricacid. There also tends to be less interference when using the concentratedphosphoric acid.11.1.3 Add a few microdrops of 5 % gold chloride to theedge of the acid solution on the microscope slide.11.1.4 Observe the formation of the
25、crystals using a prop-erly aligned and adjusted light microscope. This observationcan be done between crossed polars if desired. If crossed polarsare to be used, orient the polarizer in the east-west directionand the analyzer in the north-south direction, verified by ablack background.11.1.5 The cry
26、stals formed will depend on the drug present,as well as, the optical isomer present for the drug. Theformations that can be expected for methamphetamine andamphetamine are as follows.11.1.5.1 d- or l-Amphetamine, produces long yellow rods orblades.11.1.5.2 d,l-Amphetamine, produces irregular blades,
27、 whichhave serrated edges and often will grow in groups of three ormore.11.1.5.3 d- or l-Methamphetamine, produces long bladesand jointed crystals. If these crystals are broken gently byscratching with a probe, they will break apart into smaller rods,which have an appearance of clothespins, which ar
28、e open onone end and closed on the other. These smaller rods are bestviewed between crossed polars.11.1.5.4 d,l-Methamphetamine, produces long blades andjointed crystals similar to those observed for the d- or l- form.If these crystals are broken gently by scratching with a probe,they will break apa
29、rt into smaller rods, which are open on bothends, having an appearance of the letter “X.”11.1.6 If a dense cloud of precipitate is formed upon theaddition of the precipitating agent, the crystals may not bereadily visible. It may be necessary to repeat the test reducingthe concentration of suspected
30、 methamphetamine or amphet-amine in the acid solution. This is done by either decreasing thesample size or increasing the volume of solvent.11.1.7 The following procedure to separate the metham-phetamine or amphetamine from diluents may be used.11.1.7.1 Place a small amount of the sample into a spot
31、 well.Sample size should be approximately 2 to 3 mg.11.1.7.2 Add a small volume of 1.0 N to 10.0 N sodiumhydroxide, such that the powder is just covered.11.1.7.3 Place a microdrop of concentrated phosphoric acid,or gold chloride reagent containing phosphoric acid, on a slideand invert the slide over
32、 the sample such that the microdrop isover the spot well containing the sample.E1969 11211.1.7.4 Any amine present, including methamphetamineand amphetamine, will be converted to the free base form.Many free bases are volatile at room temperature, and as theyleave the solution, they will collect in
33、the microdrop ofphosphoric acid.11.1.7.5 After a period of time has elapsed, approximately 1to 3 min, remove the slide and observe the crystals formeddirectly if gold chloride is used in the hanging drop, or performthe testing procedure described in 11.1.3-11.1.5 on the micro-drop of phosphoric acid
34、. The appropriate period of time isvariable and will depend on the concentration of methamphet-amine or amphetamine in the sample, the diluents present, aswell as the room temperature. It may be necessary to repeat thetest for a shorter or longer duration or utilize more sample ifadequate recovery o
35、f amines is not accomplished during initialattempts.11.2 Platinum Chloride:11.2.1 Place a small sample, a few particles of powder, lessthan 1 mg, of the suspected methamphetamine or amphetamineon a microscope slide.11.2.2 Dissolve the sample in a few microdrops of 10 %hydrochloric acid or concentrat
36、ed phosphoric acid.NOTE 2The crystals tend to precipitate faster from the phosphoricacid. There also tends to be less interference when using the concentratedphosphoric acid.11.2.3 Add a few microdrops of 5 % platinum chloride tothe edge of the acid solution on the microscope slide.11.2.4 Observe th
37、e formation of the crystals using a prop-erly aligned and adjusted light microscope. This observationcan be done between crossed polars if desired. If crossed polarsare to be used, orient the polarizer in the east-west directionand the analyzer in the north-south direction, verified by ablack backgr
38、ound.11.2.5 The crystals formed will depend on the drug present,as well as the optical isomer present for the drug. Theformations that can be expected for methamphetamine andamphetamine are as follows.11.2.5.1 d- or l-Amphetamine, produces long needles, whichoften are bent and which will grow into l
39、ong rectangularblades.11.2.5.2 d,l-Amphetamine, produces irregular blades andneedles, which will grow into plates with irregular arms ofblades.11.2.5.3 d- or l-Methamphetamine, produces grains withsharp edges, which aggregate in a skeletal crystal having anappearance of ferns. The ends of the branch
40、es of the fernstructure tend to bend at a sharp angle to the branches.11.2.5.4 d,l-Methamphetamine, produces grains with sharpedges, which aggregate in a skeletal crystal having an appear-ance of ferns. The ends of the branches of the fern structuretend to be straight and not bent.11.2.6 If a dense
41、cloud of precipitate is formed upon theaddition of the precipitating agent, the microcrystals may notbe readily visible. It may be necessary to repeat the testreducing the concentration of suspected methamphetamine oramphetamine in the acid solution. This reduction is done byeither decreasing the sa
42、mple size or increasing the volume ofsolvent.11.2.7 The following procedure may be used to separate themethamphetamine or amphetamine from diluents.11.2.7.1 Place a small amount of the sample into a spot well.Sample size should be approximately 2 to 3 mg.11.2.7.2 Add a small volume of 1.0 N to 10.0
43、N sodiumhydroxide, such that the powder is just covered.11.2.7.3 Place a microdrop of concentrated phosphoric acid,or platinum chloride reagent containing phosphoric acid, on aslide and invert the slide over the sample such that themicrodrop is over the spot well containing the sample.11.2.7.4 Any a
44、mine present, including methamphetamineand amphetamine, will be converted to the free base form. Thefree bases are volatile at room temperature, and as they leavethe solution, they will collect in the microdrop of phosphoricacid.11.2.7.5 After a period of time has elapsed, approximately 1to 3 min, r
45、emove the slide and observe the crystal formeddirectly if platinum chloride is used in the hanging drop, orperform the testing procedure described in 11.2.3-11.2.5. Theappropriate period of time is variable and will depend on theconcentration of methamphetamine or amphetamine in thesample, the dilue
46、nts present, as well as the room temperature.It may be necessary to repeat the test for a shorter or longerduration or utilize more sample if adequate recovery of aminesis not accomplished during initial attempts.12. Interpretation of Results (7)12.1 The two precipitating reagents utilized in this p
47、roce-dure, that is, gold chloride and platinum chloride, are capableof distinguishing methamphetamine and amphetamine fromeach other. These tests also can be used to determine whetheran optically active form (d- or l-) or a racemic mixture ( d, l-)of the particular drug is present (3).12.2 If crysta
48、ls structurally similar to those formed bymethamphetamine or amphetamine standards are formed byboth precipitating reagents, the sample may be consideredpositive by this technique for the presence of methamphet-amine or amphetamine.12.3 All observed crystalline precipitates must be docu-mented and i
49、ncluded in the analysts notes for each itemanalyzed.12.4 The forensic identification of methamphetamine oramphetamine requires the use of multiple uncorrelated tech-niques, see Practice E2329.13. Precision and Bias13.1 No information is presented about either the precisionor bias of this technique.14. Keywords14.1 amphetamine; methamphetamine; microcrystallinetestingE1969 113REFERENCES(1) Fulton, C., “Modern Microcrystal Tests for Drugs,” Wiley-Interscience, New York, NY, 1969.(2) Clarke, E.G.C., “Isolation and Identification of Drugs,” Pharmaceu-tical Press, Londo
