1、Designation: E2548 111E2548 16Standard Guide forSampling Seized Drugs for Qualitative and QuantitativeAnalysis1This standard is issued under the fixed designation E2548; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEEditorial corrections were made to Sections 1 and 8 in December 2011.1. Scope1.1 This guide covers minimum considerations for
3、 sampling of seized drugs for qualitative and quantitative analysis.1.2 This guide cannot replace knowledge, skill, or ability acquired through appropriate education, training, and experience andshould be used in conjunction with sound professional judgment.2. Referenced Documents2.1 ASTM Standards:
4、2E105 Practice for Probability Sampling of MaterialsE122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcessE141 Practice for Acceptance of Evidence Based on the Results of Probability SamplingE1732 Terminology Relating to F
5、orensic ScienceE2329 Practice for Identification of Seized DrugsE2334 Practice for Setting an Upper Confidence Bound For a Fraction or Number of Non-Conforming items, or a Rate ofOccurrence for Non-conformities, Using Attribute Data, When There is a Zero Response in the Sample2.2 ISO Standards:3ISO
6、3534-1 Statistics Vocabulary and Symbols Part 1: Probability and General Statistical TermsISO 3534-2 Statistics Vocabulary and Symbols Part 2: Statistical Quality Control3. Significance and Use3.1 This guide provides information for the sampling of seized-drug submissions.3.2 The principal purpose o
7、f sampling in the context of this guide is to answer relevant questions about a population byexamination of a portion of the population. For example:What is the net weight of the population?What portion of the units of a population can be said to contain agiven drug at a given level of confidence?3.
8、3 By developing a sampling strategy and implementing appropriate sampling schemes, as illustrated in Fig. 1, a laboratorywill minimize the total number of required analytical determinations, while ensuring that all relevant legal and scientificrequirements are met.4. Sampling Strategy4.1 AAn appropr
9、iate sampling strategy is highly dependent on the purpose of the investigation, the original question,customersrequest, and the ultimateanticipated use of the results. Laws and legal practices form the foundation of most strategies and shallbe taken into account when designing a sampling scheme. The
10、refore, specific sampling strategies are not defined in this guide.1 This guide 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 Sept. 1, 2011March 1, 2016. Published October 2011Ap
11、ril 2016. Originally approved in 2007. Last previous version approved in 20072011 asE2548 07. 11. DOI: 10.1520/E2548-11E01.10.1520/E2548-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume
12、 information, refer to the standards Document Summary page on the ASTM website.3 Available from International Organization for Standardization (ISO), 1 rue de Varemb, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.This document is not an ASTM standard and is intended only to prov
13、ide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the
14、standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The laboratory has the responsibility to develop its own strategies consistent with these recommendations.this
15、 guide. It isrecommended that the following key points be addressed:4.2.1 Sampling may be statistical or non-statistical.NOTE 1For the purpose of this guide, the use of the term statistical is meant to include the notion of an approach that is probability-based.4.2.1.1 In many cases, a non-statistic
16、al approach may suffice. The sampling plan shall provide an adequate basis for answeringquestions of applicable law. For example,Is there a drug present in the population?Are statutory enhancement levels satisfied by the analysis of aspecified number of units?4.2.1.2 If an inference about the whole
17、population is to be drawn from a sample, then the plan shall be statistically based eitherstatistically based or have an appropriate statistical analysis completed and limits of the inference shall be documented.4.2.2 Statistically selected Selected units shall be analyzed to meet Practice E2329 if
18、statistical inferences are to be made aboutthe whole population.5. Sampling Scheme5.1 The sampling scheme is an overall approach that includes population determination, selection of the sampling plan andprocedure and, when appropriate, sample reduction prior to analysis (Fig. 2).FIG. 1 Relationship
19、of Various Levels Required in SamplingE2548 1625.2 Population Determination:5.2.1 The population determination shall take into account all typical forms and quantities in which exhibits may appear.5.2.2 A population can consist of a single unit or multiple units.5.2.3 A multiple unit population shal
20、l consist of items that are similar in relevant visual characteristics.characteristics (forexample, size, color, shape, etc.).SAMPLING PLAN5.3 There are numerous sampling plans used in the forensic analysis of drugs that are applicable to single and multiple unitpopulations.5.4 When a single unit or
21、 bulk population is to be analyzed, the issue of homogeneity shall be addressed within the samplingplan.5.4.1 One sample is sufficient if the bulk material is homogeneous. Analysts can make bulk material homogeneous.5.4.2 If the bulk material is not homogeneous, several samples from different locati
22、ons may be necessary to ensure that the testresults are representative of the bulk material and to avoid false negative results.5.5 Depending upon the inference to be drawn from the analysis for For a multiple unit population, the sampling plan may bestatistical or non-statistical.5.5.1 Statistical
23、approaches are applicable when inferences are made about the whole population. For example:The probability that a given percentage of the population containsthe drug of interest or is positive for a given characteristic.The total net weight of the population is to be extrapolated from theweight of a
24、 sample.5.5.1.1 Published examples of statistical approaches involving general considerations:FIG. 2 Example of a Sampling SchemeA Decision FlowchartE2548 163(1) Practice E105.(2) Practice E141.(3) Terminology E1732.(4) Guidelines on Representative Drug Sampling.4(5) ISO 3534-1.(6) ISO 3534-2.5.5.1.
25、2 Published examples of statistical approaches involving the hypergeometric, normal, and other distributions from afrequentist perspective:(1) Frank, et al., Journal of Forensic Sciences.5(2) Guidelines on Representative Drug Sampling.4(3) Practice E2334.(4) Practice E122.5.5.1.3 Published examples
26、of statistical approaches involving the hypergeometric, normal, and other distributions from aBayesian perspective:(1) Coulson, et al., Journal of Forensic Sciences.6(2) Guidelines on Representative Drug Sampling.45.5.2 Non-statistical approaches are appropriate if no inference is to be made about t
27、he whole population.5.5.2.1 Published examples:(1) The “square root method.”7(2) Methods listed in “Arbitrary Sampling” in Guidelines on Representative Drug Sampling.45.5.2.2 Selection of a single unit from a multiple unit population may be appropriate under certain circumstances (for example,manage
28、ment directives and legislative or judicial requirements, or both).5.5.2.3 A non-statistical sampling approach may allow an inference about the population. If a single population has beenrandomly sampled, the data may allow an inference to be drawn by (1) determining and reporting a confidence inter
29、val for aninferred population parameter (for example: weight or tablet count); or by (2) retrospectively using the results in a statistical modeland determining the resulting probabilities and level of confidence.5.6 Sampling Procedure:5.6.1 Establish the procedure for selecting the number of units
30、that will comprise a sample.5.6.1.1 For non-statistical approaches, select a sample appropriate for the analytical objectives.5.6.1.2 For statistical approaches it is recommended that approaches, random sampling shall be conducted.5.6.2 Select a Random Sample:5.6.2.1 A random sample is one selected
31、without bias. bias and where each item has an equal chance of being selected.Computer generated random numbers or random number tables are commonly employed for such tasks and these should beincluded in the sampling plan.5.6.2.2 Random sampling of items using random number tables may not be practica
32、l in all cases. In these instances, an alternatesampling plan shall be designed and documented to approach random selection. A practical solution involves a “black box”method, which refers to one that will prevent the sampler from consciously selecting a specific item from the population (that is,al
33、l units are placed in a box and the samples for testing are selected without bias). Random sampling is discussed in the followingreferences:(1) Practice E105.(2) Frank, et al., Journal of Forensic Sciences.5(3) ISO 3534-1.(4) ISO 3534-2.5.7 Sample ReductionSample reduction may be applied in cases wh
34、ere the weight or volume of the selected units is too largefor laboratory analysis (Fig. 2, insert A).6. Analysis6.1 Statistically Selected Sample(s)In accordance with 4.2.2, it is recommended that each unit comprising the sample beanalyzed to meet Practice E2329 if statistical inferences are to be
35、made about the whole population.6.2 Non-statistically Selected Sample(s)Practice E2329 shall be applied to at least one unit of the sample.4 2009 UNODC/ENFSI Guidelines on Representative Drug Sampling, European Network of Forensic Science InstitutesSampling, European Network of Forensic ScienceInsti
36、tutes (ENFSI), 2004, http:/www.ENFSI.org.5 Frank et al., “Representative Sampling of Drug Seizures in Multiple Containers,” Journal of Forensic Sciences, , Vol 36, No. 2, 1991, pp. 350357.6 Coulson et al., “How Many Samples from a Drug Seizure Need to Be Analyzed?,” Journal of Forensic Sciences, Vol
37、 46, No. 6, 2001, pp. 14561461.7 Recommended Methods for Testing Opium, Morphine and Heroin: Manual for Use by National Drug Testing Laboratories, United Nations Office on Drugs and Crime,1998.E2548 1647. Documentation7.1 Inferences based on use of adrawn from the application of the sampling plan an
38、d concomitant analysissubsequent analysesshall be documented.8. Reporting8.1 Sampling information shall be included in reports.8.1.1 Statistically Selected Sample(s)Reporting statistical inferences for a population is acceptable when testing is performedon the statistically selected units as stated
39、in 6.1 above. The language in the report must make it clear to the reader that the resultsare based on a probability-based sampling plan.8.1.2 Non-Statistically Selected Sample(s)The language in the report must make it clear to the reader that the results applyto only the tested units. For example,
40、2 of 100 bags were analyzed and found to contain Cocaine.9. Keywords9.1 analytical method; qualitative method; quantitative method; sampling; seized drug analytical methodASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedi
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