1、Designation: E2520 07E2520 15Standard Practice forVerifying Minimum AcceptableMeasuring and ScoringPerformance of Trace Explosive Chemical Detectors1This standard is issued under the fixed designation E2520; the number immediately following the designation indicates the year oforiginal adoption or,
2、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.1. Scope1.1 This practice is primarily intended to assist first responders and security scree
3、ners in verifying the minimum acceptable maybe used for measuring, scoring, and improving the overall performance of detectors used to identifythat alarm on traces of highexplosives such as cyclotrimethylene trinitramine (RDX), pentaerythritol tetranitrate (PETN), and trinitrotoluene (TNT). Theseexp
4、losive detectors explosives on swabs. These explosive trace detectors (ETDs) may be based on, but are not limited to, chemicaldetection technologies such as ion mobility spectrometry (IMS).(IMS) and mass spectrometry (MS). Technologies that usethermodynamic or optical detection are not specifically
5、addressed, but may be adapted into future versions of this practice.1.2 This practice is used to evaluate the detector response to evaporated residues of low-concentration solutions of explosivecompounds placed on test swipes. The solutionsconsiders instrumental (post-sampling) trace detection perfo
6、rmance, involvingspecific chemical analytes across eight types of explosive formulations in the presence of a standard background challengematerial. This practice adapts Test Method E2677 used for this evaluation are prepared in a suitable organic solvent and containa single high explosive. for the
7、evaluation of limit of detection, a combined metric of measurement sensitivity and repeatability,which requires ETDs to have numerical responses.1.3 This practice considers the effective detection throughput of an ETD by factoring in the sampling rate, interrogated swabarea, and estimated maintenanc
8、e requirements during a typical eight hour shift.1.4 This practice does not address or use sampling procedures common to the use of trace explosive detectors. It only tests theresponse of the detector once a test swipe has been successfully introduced into the explosive detector.require, but places
9、extravalue on, the specific identification of targeted compounds and explosive formulations.1.5 This practice requires the use of a single set of ETD operational settings for calculating a system test score based on thefactors described in 1.2, 1.3, and 1.4. A minimum acceptable score is derived fro
10、m criteria established in Practice E2520 07.1.6 Intended UsersETD developers and manufacturers, testing laboratories, and international agencies responsible forenabling effective deterrents to terrorism.1.7 Actual explosives as test samples would be preferable, but standard explosive formulations ar
11、e not widely available, nor aremethods for depositing these quantitatively and realistically on swabs. This practice considers sixteen compounds that are availablefrom commercial suppliers. This does not imply that only these sixteen are important to trace detection. Most ETDs are able todetect many
12、 other compounds, but these are either chemically similar (hence redundant) to the ones considered, or are unavailablefrom commercial suppliers for reasons of stability and safety. Under typical laboratory practices, the sixteen compounds consideredare safe to handle in the quantities used.1.8 This
13、practice is not intended to replace any current standard procedure employed by agencies to test performance of ETDsfor specific applications. Those procedures may be more rigorous, use different compounds or actual explosive formulations,employ different or more realistic background challenges, and
14、consider environmental sampling procedures and other operationalvariables.1.9 This practice does not evaluate the effect of contaminants or interferences that may be encountered in sampling for traceexplosives in the field.recommends one method for preparation of test swabs, pipetting, because this
15、method is simple,reproducible, quantitative, documented, and applicable to most current detection technologies. Other methods, such as inkjet1 This practice is under the jurisdiction of ASTM Committee E54 on Homeland Security Applications and is the direct responsibility of Subcommittee E54.01 on CB
16、RNESensors and Detectors.Current edition approved Feb. 1, 2007Feb. 1, 2015. Published March 2007February 2015. Originally approved in 2007. Last previous edition approved in 2007 asE2520 07. DOI: 10.1520/E2520-07.10.1520/E2520-15.This document is not an ASTM standard and is intended only to provide
17、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 stan
18、dard 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 States1printing and dry transfer, may generate more realistic analyte distributions and particle sizes, but these methods are
19、 not widelyavailable and less familiar. They may be used if the procedures are validated and documented properly.1.10 With any deposition method, some compounds are difficult to present to the ETD inlet quantitatively due to volatility andloss during the swab preparation process. Problematic issues
20、pertinent to this practice are identified along with recommendedinstructions. The user should be aware of the possibility that untested scenarios may lead to failure in the determination of reliabletest scores.1.11 UnitsThe values stated in SI units are to be regarded as standard. No other units of
21、measurement are included in thisstandard.1.12 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
22、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1154 Specification for Piston or Plunger Operated Volumetric ApparatusE2677 Test Method for Determining Limits of Detection in Explosive Trace DetectorsE2771 Terminology for Homeland Security Applications3. Terminology3.1 Definitio
23、ns of Terms Specific to This Standard:3.1.1 blank solution, alarm, nsemivolatile solvent that does not contain trace explosives to which the detector issensitive.visual or audible response, or both, from an ETD that signifies the detection of an explosive.3.1.2 ambient background, nparticular mixtur
24、e of environmental substances (dust, dirt, etc.) that is collected during swabsampling.3.1.2.1 DiscussionThe chemical background collected on swabs is expected to be highly variable, compositionally and temporally, comprised of anearly unlimited number of possible chemical species and formulations.
25、Background challenge materials (BCMs) should mimicimportant types of chemical background found in ETD deployment areas.3.1.3 background challenge material, BCM, na standard natural matrix material applied on a test swab to challenge thedetection performance of an ETD.3.1.3.1 DiscussionA BCM should b
26、e a well-documented material that closely mimics the ambient background typically collected during swabsampling. Many certified reference materials, derived from a variety of natural matrices and processed to offer stable andreproducible characteristics, are internationally available from standards
27、suppliers. The BCMs recommended here are StandardReference Materials (SRMs). While these represent a limited number of natural matrices, they are compositionally complex andoffer fair detection challenges to ETDs.3.1.4 clear-down, nthe process of allowing an ETD to recover from an alarm through a re
28、peated sequence of automatedcleansing to clear out the residual sample from the instrument until the signal is reduced below a set threshold.3.1.4.1 DiscussionMay also be used as a verb, for example: “Enough time was allowed to clear-down the ETD.”3.1.5 calibration, compound identity calibration (CI
29、C), nact of providing the detector with a known substance so that it theinternal software parameters may be adjusted to identify explosive compounds correctly.3.1.5.1 Discussion2 Verkouteren, J., Gillen, G., Verkouteren, R. M., Fletcher, R., Etz, E., et al., “IMS-Based Trace Explosives Detectors for
30、 First Responders,” For referenced ASTMstandards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For NIST IR 7240, System Assessment and Validation forEmergency Responders,Annual Book of ASTM Standards U.S. Department of Homeland Security, Washington, DC 2
31、0528. This document is summarized on the web pagehttp:/saver.tamu.edu/documents.php?fl=336 improvements in scope, SSRs, and ESRs will result in higher scores.3.1.12 test solution, ndilute solution of a single explosive compound dissolved in a semivolatile solvent.3.1.13 test swipe,swab, na sample sw
32、ipeswab that has been dosed with one of the performance evaluation solutions anddried.the BCM and target compound within the EA.2.1.10 trace explosives detector, nan instrument designed to detect trace amounts (micrograms or less) of explosivecompounds.2.1.10.1 DiscussionIn the context of this stand
33、ard practice, a trace explosives detector will require the use of a swipe sample collector. These detectorsare commonly based on, but not limited to, ion mobility spectrometry.3.2 Acronyms:3.2.1 AN, nammonium nitrate3.2.2 BCM, nbackground challenge material (see 3.1.3).3.2.3 CAN, ncalcium ammonium n
34、itrate 5Ca(NO3)2+NH4NO3+10H2O3.2.4 CIC, ncompound identity calibration3.2.5 COTS, ncommercial off-the-shelf3.2.6 EA, neffective area of the swab (see 3.1.9)3.2.7 ESR, ncombined metric for effective sampling rate performance (see 6.5 and 6.7)3.2.8 EtC, nethyl centralite (IUPAC: 1,3-diethyl-1,3-diphen
35、ylurea)3.2.9 ETD, nexplosive trace detector (see 3.1.6)3.2.10 ETN, nerythritol tetranitrate (IUPAC: (2R, 3R)-1,3,4-Trinitrooxybutan-2-yl nitrate)3.2.11 HMTD, nhexamethylene triperoxide diamine (IUPAC: 3,4,8,9,12,13-Hexaoxa-1,6-diazabicyclo4.4.4 tetradecane)3.2.12 HMX, nhigh melting explosive (IUPAC:
36、 Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)3.2.13 IMS, nion mobility spectrometry3.2.14 KClO4, npotassium perchlorate3.2.15 KNO3, npotassium nitrate3.2.16 LOD90A, nlimit of detection for 90 % alarm rate (see 3.1.7)3.2.17 MS, nmass spectrometry3.2.18 NaClO3, nsodium chlorate3.2.19 NG, nnitrogl
37、ycerin (IUPAC: 1,2,3-Trinitroxypropane)E2520 1543.2.20 OEM, noriginal equipment manufacturer3.2.21 PETN, npentaerythritol tetranitrate (IUPAC: 3-Nitrooxy-2,2-bis(nitrooxymethyl)propyl nitrate)3.2.22 RDX, ncyclotrimethylene trinitramine research department explosive (IUPAC: 1,3,5-Trinitroperhydro-1,3
38、,5-triazine)3.2.23 R-salt, ncyclotrimethylenetrinitrosamine (IUPAC: hexahydro-1,3,5-trinitroso-1,3,5-triazine)3.2.24 SRM, nStandard Reference Material, certified and distributed by the National Institute of Standards and Technology,Gaithersburg, MD, USA.3.2.25 SSR, ncombined metric for sensitivity/s
39、electivity/repeatability performance (see 6.7)3.2.26 TATP, ntriacetone triperoxide (IUPAC: 3,3-Dimethyl-1,2-dioxacyclopropane)3.2.27 Tetryl, n2,4,6-trinitrophenylmethylnitramine (IUPAC: N-methyl-N,2,4,6-tetranitroaniline)3.2.28 TNT, ntrinitrotoluene (IUPAC: 2-Methyl-1,3,5-trinitrobenzene)3.3 General
40、 Terms:3.3.1 Please refer to Terminology E2771.4. Summary of Practice4.1 Based on the capabilities of the ETD detection technology, select particular target compounds to be measured and theidentity of BCM.4.2 Reference solutions are prepared, each containing a known concentration of a particular tar
41、get compound.4.3 Assure all target compounds are programmed into the ETD under test, and that standard operating conditions are set.4.4 Each test swab is pretreated with 100 g of BCM.4.5 Using the manufacturers instructions, perform steps to assure that the ETD is in operational readiness. This may
42、involvecompound identity calibration (CIC), verification, and minor tuning. Note the time needed to perform these tasks.4.6 Twenty-five process blank swabs are analyzed to determine the background response and the basic sampling rate.4.7 Determine the LOD90A for each target compound selected. Via pi
43、pette or syringe, BCM and target compound are placedanywhere within the EAof the swab as defined by the ETD manufacturer. Between analyses, the time is noted to recalibrate, retune,and troubleshoot the ETD system in order to maintain operational readiness.4.8 An ETD score is calculated through a for
44、mula using the LOD90Avalues achieved for each target compound, the selectivityof each alarm, and the effective rate of sample throughput.5. Significance and Use5.1 The practice may be used to accomplish several ends: to compare detectors before purchase; establish a worldwide frameof reference for t
45、erminology, metrics, and procedures for reliably determining trace detection performance of ETDs; to givedevelopers tangible benchmarks designed to improve detection performance of next-generation ETDs; as a demonstration by thevendor that the equipment is performingoperating properly to a minimal s
46、tandard; orspecified performance score; for a periodicverification by the user of detector performance after purchase. purchase; and as a generally-acceptable template adaptable byinternational agencies to specify performance requirements, analytes and dosing levels, background challenges, and opera
47、tions.5.2 This It is expected that current ETD systems will exhibit wide ranges of performance across the diverse explosive types andcompounds considered. As in previous versions, this practice establishes the minimum performance that is required for a detectorto be considered effective in the detec
48、tion of trace explosives. An explosives detector is considered to have “minimum acceptableperformance” when it has passed all of the evaluation tests without a failure.attained a test score of at least 80.3.3 This practice uses three explosive compoundsRDX, PETN, and TNTthat are used to represent ni
49、tro-based compoundshaving a range of physical and chemical properties. The concentrations of the solutions of explosive have been determined to besufficient to provide a positive detector alarm signal. In time, other compounds may be added or substituted into this practice asdetection priorities dictate.3.4 This practice was developed using IMS-based trace explosives detectors, but this practice should also be applicable to anyexplosives detector designed to analyze trace levels of high-explosive compounds collected on swipe
