ASTM E2125-19

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Designation: E2125 − 11 E2125 − 19
Standard GuidePractice for
Microcrystal Testing in Forensic Analysis offor
Phencyclidine and Its Analogues
This standard is issued under the fixed designation E2125; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Microcrystal tests are primarily chemical-precipitation tests in which a light microscope is used to
observe and distinguish the different types of crystals formed. These tests require skill and expertise
on the part of the analyst that can be adequately gained only through appropriate training and
experience in their use. These tests should not be attempted by those who are unfamiliar with them
for use in the analysis of phencyclidine and its analogues.
1. Scope
1.1 This guidepractice describes some standard procedures applicable to the analysis of phencyclidine and its analogues using
microcrystal tests (1-8).
1.2 These procedures are applicable to phencyclidmephencyclidine and its analogues which are present in solid dosage form or
in a liquid form. They are not typically applicable to the analysis of phencyclidine and its analogues in biological samples.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 These procedures could generate observations indicating a positive test for phencyclidine and its analogues which could
be incorporated into the analytical scheme as defined by the laboratory.
1.5 This standard cannot replace knowledge, skill,skills, or abilityabilities acquired through appropriate education, training,
and experience (see Practice E2326) and should is to be used in conjunction with sound professional judgment.judgment by
individuals with such discipline-specific knowledge, skills, and abilities.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E1459 Guide for Physical Evidence Labeling and Related Documentation
E1492 Practice for Receiving, Documenting, Storing, and Retrieving Evidence in a Forensic Science Laboratory
E1732 Terminology Relating to Forensic Science
E2326 Practice for Education and Training of Seized-Drug Analysts
E2329 Practice for Identification of Seized Drugs
E2548 Guide for Sampling Seized Drugs for Qualitative and Quantitative Analysis
E2764 Practice for Uncertainty Assessment in the Context of Seized-Drug Analysis
This guidepractice is under the jurisdiction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.
Current edition approved March 1, 2011Nov. 1, 2019. Published April 2011December 2019. Originally approved in 2001. Last previous edition approved in 20072011
as E2125 – 07.E2125 – 11. DOI: 10.1520/E2125-11.10.1520/E2125-19.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2125 − 19
3. Terminology
3.1 For definitions of terms used in this standard, refer to Terminology E1732.Definitions:
3.1.1 For definitions of terms used in this standard, refer to Terminology E1732.
3.2 Definitions:Definitions of Terms Specific to This Standard:
3.2.1 aggregation—aggregation, n—the collecting of units or parts into a mass or whole.
3.2.2 birefringence—birefringence, n—property of some crystals crystals, those having more than one refractive index; this will
result in interference colors which are viewed through a polarized light microscope.
3.2.2.1 birefringent, adj—material exhibiting birefringence.
3.2.3 grains—grains, n—thick tablets having nearly equal width, breadth, and thickness.
3.2.4 habit—habit, n—the external morphology of the crystal.
3.2.5 microdrop—microdrop, n—a small drop of liquid that would fit on the end of a standard size, flattened toothpick; the
approximate volume of this drop would be 10 to 25 μL.
3.2.6 nails—nails, n—a skeleton of some kinds of triangles, elongated, usually pointed with a short head usually thicker or
broader.
3.2.7 needles (acicular)—(acicular), n—long, thin crystals with pointed ends.
3.2.8 nuggets—nuggets, n—irregularly formed grains without sharp faces or edges.
3.2.9 pliers—pliers, n—crystals resembling pliers, generally X-shaped.
3.2.10 razor blades—blades, n—thin oblong crystals with length about twice the width, resembling a safety razor blade.
3.2.11 sheaves—sheaves, n—elongated crystals form two opposite fans from the same joining point.
3.2.12 skeletal crystal—crystal, n—a crystal in which all of the spaces in the crystal lattice are not occupied.
3.2.13 spindles—spindles, n—shorter than course needles, but more substantial cross-section.
4. Summary of the Technique
4.1 A small sampleamount of thetest material containing the suspected phencyclidine or its analogues is dissolved in a dilute
acid and the appropriate precipitating reagent is added. The crystals that are formed are observed and distinguished utilizing a light
microscope.
5. Significance and Use
5.1 TheThis technique producesinvolves a chemical-precipitation reaction between the phencyclidine or its analogues and the
precipitating reagent. The habit and the aggregation of the crystals formed maycould be used to distinguish phencyclidine or its
analogues from other drugs.
5.2 TheThis technique can be utilized on phencyclidine or its analogues present in either the salt or free base form.
5.3 TheThis technique does not distinguish between salt and free base forms.
6. Interferences
6.1 Diluents/adulterants present in combination with phencyclidine or its analogues in the sample to be tested may result in
could inhibit crystal formation or could generate crystals that are distorted or otherwise rendered unidentifiable. Diluting the
sample could reduce the interference. The higher the concentration of the adulterant, the more difficult it will be to observe
characteristic crystals. In these instances, it will be necessary to separate the phencyclidine or its analogues from the
diluents/adulterants or to use other testing methods to analyze for phencyclidine or its analogues.
7. Apparatus
7.1 Standard Light Microscope, Standard light microscope capable of varying magnifications including 100× is needed for
viewing the crystals. Polarized This is the minimum equipment required. A polarized light attachment is not essential, but is
desirable because crystals resulting from the precipitation reaction are birefringent.
7.1.1 Polarized Light Microscope (PLM), capable of varying magnifications from 40× to 400×. The following are typical
accessories on a PLM and could be useful, but are not required, to conduct microcrystalline testing: specialized rotating stage
(360°) and compensator (retardation plate). Cross-polarizers are verified by observing a black background when the polarizer and
analyzer are in the optical path at 90 degrees to one another (for example, polarizer is in the east-west direction and the analyzer
is in the north-south direction).
7.1.2 The best practice for documenting the crystal formation results is to take a digital photograph. It is advised that the
minimum equipment required also has the capability of digital photography.
E2125 − 19
8. Reagents and Materials
8.1 10 % Solution of Acetic Acid 10 % v:v(hereafter, dilute acetic acid.acid).
8.2 10 % Solution of Hydrochloric Acid 10 % v:v(hereafter, dilute hydrochloric acid.acid).
8.3 2 % w:v potassium permanganate Potassium Permanganate in 0.5 % v:v phosphoric Phosphoric Acid.acid.
8.4 Gold Bromide (HAuBr ) in Diluted Perchloric and Acetic Acids Gold bromide (HAuBr ) in diluted perchloric and acetic
4 4
acids [0.55 g HAuBr , 42 mL distilled water, 37 mL concentrated perchloric acid, 21 mL glacial acetic acid].
8.5 Gold Chloride (HAuCl ) in Acetic and Sulfuric Acids Gold chloride (HAuCl[2 g ) in acetic and sulfuric acids [HAuCl in
4 4 4
HOAc-4(1+1)H SO ; 2 g HAuCl , 20 mL glacial acetic acid, 40 mL concentrated sulfuric acid, 40 mL distilled water].
2 4 4
8.6 Phencyclidine [PCP; 1-(1-phenylcyclohexyl)piperidine] standard.Standard.
8.7 Pyrrolidine analogueAnalogue of phencyclidinePhencyclidine [PCPy, PHP,
1-(1-phenylcyclohexyl)pyrrolidine] standard.Standard.
8.8 Morpholine analogueAnalogue of phencyclidinePhencyclidine [PCM,
1-(1-phenylcyclohexyl)morpholine] standard.Standard.
8.9 Thiophene analogueAnalogue of phencyclidinePhencyclidine [TCP;
1-[l-(2thienyl)cyclohexyl]piperidine] standard.Standard.
9. Sampling, Test Specimens, and TextTest Units
9.1 The general handling and tracking of samples should meet or exceed the requirements of Practice E1492 and Guides E1459
and E2548.
10. Calibration and StandardizationPerformance Verification
10.1 The reagents utilizedPrior to use in casework, the reagents used for these microcrystal tests are to shall be tested for
reliability using phencyclidine or its analogues and negative controls following the prescribed procedure. Only when it is
determined that the reagents are producing the expected response mayresponse, shall 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 standard. Perform the analysis of unknown samples and standards under the same microscope operating
procedures (for example, use of cross polarizers).
11. Procedure
11.1 Potassium Permanganate:
11.1.1 Place a small sample (a few particles of powder, less than one (1) milligram (mg) or a small drop of liquid, allowed to
dry) of the suspect
...