1、Designation: E 1969 06Standard Guide forMicrocrystal Testing in the Forensic Analysis ofMethamphetamine and Amphetamine1This standard is issued under the fixed designation E 1969; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、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 th
4、e analysis of methamphetamine or amphetamine.1. Scope1.1 This guide describes some standard procedures appli-cable to the analysis of methamphetamine and amphetamineusing microcrystal tests.1.2 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 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cann
6、ot replace education orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service mu
7、st be judged, nor should thisdocument be applied without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.1.4 This standard does not purport to address all of thesafety co
8、ncerns, 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. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 aggregati
9、on, nthe collecting of units or parts into amass or whole.2.1.2 birefringence, nproperty of some crystals, havingmore than one refraction index. This property will result ininterference colors, which are viewed through a polarized lightmicroscope.2.1.3 blades, nbroad, flat, elongated crystals.2.1.4
10、grains, nthick tablets having nearly equal width,breadth and thickness.2.1.5 habit, nthe external morphology of the crystal.2.1.6 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.2.1.7 needles
11、(acicular), nlong, thin crystals with pointedends.2.1.8 plates, nblades with nearly equal length and breadthand of a thickness substantially less than the width.2.1.9 rods, nlong, thin crystals with squared off ends.2.1.10 tablets, nplates with appreciable thickness but lessthan the length or breadt
12、h.3. Summary of the Technique3.1 A small sample of the material containing the suspectedmethamphetamine or amphetamine is dissolved in an appro-priate acid and the appropriate precipitating reagent is added.1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the di
13、rect responsibility on Subcommittee E30.01 on Criminalistics.Current edition approved Aug. 1, 2006. Published September 2006. Originallyapproved in 1998. Last previous edition approved in 2001 as E 196901.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
14、2959, United States.The crystals that are formed are observed and distinguishedutilizing a light microscope.3.2 If the proper formation of crystals is inhibited by thepresence of diluents, a purification of the sample based on thevolatility of methamphetamine and amphetamine may beperformed.4. Signi
15、ficance and Use4.1 This technique produces a chemical-precipitation reac-tion between methamphetamine or amphetamine and the pre-cipitating reagent. The habit and the aggregation of the crystalsformed may be used to distinguish methamphetamine andamphetamine from other drugs.5. Interferences5.1 Dilu
16、ents/AdulterantsDiluents/adulterants present incombination with methamphetamine or amphetamine in thesample to be tested may inhibit crystal formation or result incrystals that are distorted or otherwise rendered unidentifiable.In these instances, it will be necessary to separate the meth-amphetamin
17、e or amphetamine from the diluents or to use othertesting methods to analyze the methamphetamine or amphet-amine.6. Apparatus6.1 A standard light microscope capable of varying magni-fications including 1003 is needed for viewing the crystals. Apolarized light attachment is not essential, but is desi
18、rable,because the heavy metal crystals of methamphetamine andamphetamine are birefringent.7. Reagents and Materials7.1 10 % Solution of Hydrochloric Acid.7.2 Concentrated Phosphoric Acid.7.3 1.0 N to 10.0 N Sodium Hydroxide.7.4 Gold Chloride (HAuCI4) Solution, approximately 5 %,in reagent grade wate
19、r. Gold chloride in phosphoric acid also issuitable.7.5 Platinum Chloride (H2PtC16) Solution, approximately5 %, in reagent grade water. Platinum chloride in phosphoricacid also is suitable.7.6 Authenticated Amphetamine Standard.7.7 Authenticated Methamphetamine Standard.8. Calibration and Standardiz
20、ation8.1 The reagents utilized for these microcrystal tests are tobe tested for reliability using authenticated amphetamine andmethamphetamine standards and negative controls followingthe prescribed procedure. Only when it is determined that thereagents are producing the expected response may the re
21、agentsbe used in the testing procedure.9. Procedure9.1 Gold Chloride:9.1.1 Place a small sample, a few particles of powder, lessthan 1 mg, of the suspected methamphetamine or amphetamineon a microscope slide.9.1.2 Dissolve the sample in a few microdrops of 10 %hydrochloride acid or concentrated phos
22、phoric acid.NOTE 1The crystals tend to precipitate faster from the phosphoricacid. There also tends to be less interference when using the concentratedphosphoric acid.9.1.3 Add a few microdrops of 5 % gold chloride to theedge of the acid solution on the microscope slide.9.1.4 Observe the formation o
23、f the crystals using a properlyaligned and adjusted light microscope. This observation can bedone between crossed polars if desired. If crossed polars are tobe used, orient the polarizer in the east-west direction and theanalyzer in the north-south direction, verified by a blackbackground.9.1.5 The
24、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.9.1.5.1 d- or l-Amphetamine, produces long yellow rods orblades.9.1.5.2 d, l- Amphetamine, produces irregular blad
25、es, whichhave serrated edges and often will grow in groups of three ormore.9.1.5.3 d- or l- Methamphetamine, produces long blades andjointed crystals. If these crystals are broken gently by scratch-ing with a probe, they will break apart into smaller rods, whichhave an appearance of clothespins, whi
26、ch are open on one endand closed on the other. These smaller rods are best viewedbetween crossed polars.9.1.5.4 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 bre
27、ak apart into smaller rods, which are open on bothends, having an appearance of the letter “X.”9.1.6 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 susp
28、ected methamphetamine or amphet-amine in the acid solution. This is done by either decreasing thesample size or increasing the volume of solvent.9.1.7 The following procedure to separate the methamphet-amine or amphetamine from diluents may be used.9.1.7.1 Place a small amount of the sample into a s
29、pot well.Sample size should be approximately 2 to 3 mg.9.1.7.2 Add a small volume of 1.0 N to 10.0 N sodiumhydroxide, such that the powder is just covered.9.1.7.3 Place a microdrop of concentrated phosphoric acid,or gold chloride reagent containing phosphoric acid, on a slideand invert the slide ove
30、r the sample such that the microdrop isover the spot well containing the sample.9.1.7.4 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 the micro
31、drop ofphosphoric acid.9.1.7.5 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 9.1.3-9.1.5 on the microdropof phosphoric acid. The appropri
32、ate period of time is variableand will depend on the concentration of methamphetamine orE1969062amphetamine in the sample, the diluents present, as well as theroom temperature. It may be necessary to repeat the test for ashorter or longer duration or utilize more sample if adequaterecovery of amines
33、 is not accomplished during initial attempts.9.2 Platinum Chloride:9.2.1 Place a small sample, a few particles of powder, lessthan 1 mg, of the suspected methamphetamine or amphetamineon a microscope slide.9.2.2 Dissolve the sample in a few microdrops of 10 %hydrochloric acid or concentrated phospho
34、ric acid.NOTE 2The crystals tend to precipitate faster from the phosphoricacid. There also tends to be less interference when using the concentratedphosphoric acid.9.2.3 Add a few microdrops of 5 % platinum chloride to theedge of the acid solution on the microscope slide.9.2.4 Observe the formation
35、of the crystals using a properlyaligned and adjusted light microscope. This observation can bedone between crossed polars if desired. If crossed polars are tobe used, orient the polarizer in the east-west direction and theanalyzer in the north-south direction, verified by a blackbackground.9.2.5 The
36、 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.9.2.5.1 d- or l-Amphetamine, produces long needles, whichoften are bent and which will grow into long rectangularb
37、lades.9.2.5.2 d, l-Amphetamine, produces irregular blades andneedles, which will grow into plates with irregular arms ofblades.9.2.5.3 d- or l-Methamphetamine, produces grains withsharp edges, which aggregate in a skeletal crystal having anappearance of ferns. The ends of the branches of the fernstr
38、ucture tend to bend at a sharp angle to the branches.9.2.5.4 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.9.2.6 If a dense cloud of precipit
39、ate 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 sample size or incr
40、easing the volume ofsolvent.9.2.7 The following procedure may be used to separate themethamphetamine or amphetamine from diluents.9.2.7.1 Place a small amount of the sample into a spot well.Sample size should be approximately 2 to 3 mg.9.2.7.2 Add a small volume of 1.0 N to 10.0 N sodiumhydroxide, s
41、uch that the powder is just covered.9.2.7.3 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.9.2.7.4 Any amine present, includin
42、g 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.9.2.7.5 After a period of time has elapsed, approximately 1to 3 min, remove the slide and obs
43、erve the crystal formeddirectly if platinum chloride is used in the hanging drop, orperform the testing procedure described in 9.2.3-9.2.5. Theappropriate period of time is variable and will depend on theconcentration of methamphetamine or amphetamine in thesample, the diluents present, as well as t
44、he 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.10. Interpretation of Results10.1 The two precipitating reagents utilized in this proce-dure, that is, gold chlo
45、ride 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.10.2 If crystals structurally similar to those
46、formed byauthenticated methamphetamine or amphetamine standards areformed by both precipitating reagents, then the test results maybe considered positive for the presence of methamphetamine oramphetamine.10.3 All observed crystalline precipitates must be docu-mented and included in the analysts note
47、s for each itemanalyzed.11. Precision and Bias11.1 No information is presented about either the precisionor bias of this technique.12. Keywords12.1 amphetamine; methamphetamine; microcrystallinetestingE1969063References(1) Fulton, C., “Modern Microcrystal Tests for Drugs,” Wiley-Interscience, New Yo
48、rk, NY, 1969.(2) Clarke, E.G.C., “Isolation and Identification of Drugs,” Pharmaceuti-cal Press, London, England, 1971, pp. 139141.(3) Clark, J., “Method for Differentiating Optical Isomers of Amphet-amine by the Simple and Direct Examination of Microcrystals in GoldChloride Solution,” Journal of th
49、e A.O.A.C., Vol 56, No. 5, 1973, pp.10651068.(4) Auerbach, L., “Microcrystalline Identification Test of Some Amphet-amines and Hydrochlorothiazide: Collaborative Study,” Journal of theA.O.A.C., Vol 61, No. 6, 1978, pp. 14351440.(5) Chamot, E. and Mason, C., Handbook of Chemical Microscopy: Vol I,John Wiley, New York, NY, 1930.(6) Chamot, E. and Mason, C., Handbook of Chemical Microscopy: Vol II,John Wiley, New York, NY, 1931.(7) Nichols, R., “Drug Proficiency Test False Positives: A Lack of CriticalThought,” Science and Justice, Vol 37, No. 3, pp. 191196.ASTM Interna
