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ASTM E2677-14

(Test Method)

Standard Test Method for Determining Limits of Detection in Explosive Trace Detectors

Standard Test Method for Determining Limits of Detection in Explosive Trace Detectors

SIGNIFICANCE AND USE
5.1 ETDs are used by first responders, security screeners, the military, and law enforcement to detect and identify explosive threats quickly. ETDs typically operate by detecting chemical agents in residues and particles sampled from surfaces and can have detection limits for some compounds extending below 1 ng. An ETD is set to alarm when its response to any target analyte exceeds a programmed threshold level for that analyte. Factory settings of such levels typically balance sensitivity and selectivity assuming standard operating and deployment conditions.  
5.2 A LOD is commonly accepted as the smallest amount of a particular substance that can be reliably detected in a given type of medium by a specific measurement process (2, 3). The analytical signal from this amount shall be high enough above ambient background variation to give statistical confidence that the signal is real. Methods for determining nominal LOD values are well known (for example, Hubaux and Vos (7) and Practice D6091), but pitfalls exist in specific applications. Vendors of ETDs often report detection limits for only a single compound without defining the meaning of terms or reference to the method of determination.Note 1—There are several different “detection limits” that can be determined for analytical procedures. These include the minimum detectable value, the instrument detection limit, the method detection limit, the limit of recognition, and the limit of quantitation. Even when the same terminology is used, there can be differences in the LOD according to nuances in the definition used, the assumed response model, and the type of noise contributing to the measurement.  
5.3 When deployed, individual ETD performance (for example, realistic LODs) is influenced by: (1) ETD manufacturing differences, history, and maintenance; (2) ETD operating configurations (for example, thermal desorption temperature, analyzer temperature, and type of swab); and (3) environmental conditions (for exampl...
SCOPE
1.1 In harmony with the Joint Committee for Guides in Metrology (JCGM) and detection concepts of the International Union of Pure and Applied Chemistry (IUPAC) (1, 2, 3)2, this test method uses a series of replicated measurements of an analyte at dosage levels giving instrumental responses that bracket the critical value, a truncated normal distribution model, and confidence bounds to establish a standard for determining practical and statistically robust limits of detection to analytes sampled on swabs by explosive trace detectors (ETDs).  
1.2 Here, the limit of detection (LOD90) is defined to be the lowest mass of a particular compound deposited on a sampling swab for which there is 90 % confidence that a single measurement in a particular ETD will have a true detection probability of at least 90 % and a true nondetection probability of at least 90 % when measuring a process blank sample.  
1.3 This particular test method was chosen on the basis of reliability, practicability, and comprehensiveness across tested ETDs, analytes, and deployment conditions. The calculations involved in this test method are published elsewhere (4), and may be performed consistently with an interactive web-based tool available on the National Institute of Standards and Technology (NIST) site: http://pubapps.nist.gov/loda.  
1.4 Intended Users—ETD developers, ETD vendors, ETD buyers, ETD testers, ETD users (first responders, security screeners, and the military), and agencies responsible for public safety and enabling effective deterrents to terrorism.  
1.5 While this test method may be applied to any detection technology that produces numerical output, the procedures have been designed for ion mobility spectrometry (IMS) based ETD systems and tested with low vapor pressure explosive compounds. Compounds are deposited as liquid solutions on swabs and dried before use. As some swabs are absorbent, this deposition procedure may not be opt...

General Information

Status
Historical
Publication Date
31-Jan-2014
ICS
13.230 - Explosion protection
Technical Committee
E54 - Homeland Security Applications
Drafting Committee
E54.01 - CBRNE Detection and CBRN Protection
Current Stage
Ref Project

Relations

Replaced By
ASTM E2677-20 - Standard Test Method for Estimating Limits of Detection in Trace Detectors for Explosives and Drugs of Interest
Effective Date
01-Feb-2020
Referred By
ASTM E2520-21 - Standard Practice for Measuring and Scoring Performance of Trace Explosive Chemical Detectors
Effective Date
01-Feb-2014
Referred By
ASTM E2771-11(2019) - Standard Terminology for Homeland Security Applications
Effective Date
01-Feb-2014
Referred By
ASTM E3131-17 - Standard Specification for Nucleic Acid-Based Systems for Bacterial Pathogen Screening of Suspicious Visible Powders
Effective Date
01-Feb-2014

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ASTM E2677-14 - Standard Test Method for Determining Limits of Detection in Explosive Trace DetectorsASTM E2677-14 - Standard Test Method for Determining Limits of Detection in Explosive Trace Detectors
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ASTM E2677-14 - Standard Test Method for Determining Limits of Detection in Explosive Trace Detectors
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2677 − 14
Standard Test Method for
Determining Limits of Detection in Explosive Trace
1
Detectors
This standard is issued under the fixed designation E2677; 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.
1. Scope deposition procedure may not be optimal for those ETD
technologies that rely on high coverage of analyte on the
1.1 In harmony with the Joint Committee for Guides in
surface of the swab. Background interferences introduced to
Metrology (JCGM) and detection concepts of the International
2 the test samples were representative of a variety of conditions
Union of Pure andApplied Chemistry (IUPAC) (1, 2, 3) , this
expected during deployment, but these conditions were not
test method uses a series of replicated measurements of an
intended as comprehensive in representing all possible sce-
analyte at dosage levels giving instrumental responses that
narios.Theusershouldbeawareofthepossibilitythatuntested
bracket the critical value, a truncated normal distribution
scenarios may lead to failure in the determination of a reliable
model, and confidence bounds to establish a standard for
LOD90 value.
determiningpracticalandstatisticallyrobustlimitsofdetection
to analytes sampled on swabs by explosive trace detectors 1.6 Units—The values stated in SI units are to be regarded
(ETDs). as the standard. No other units of measurement are included in
this standard.
1.2 Here, the limit of detection (LOD90) is defined to be the
1.7 This standard does not purport to address all of the
lowest mass of a particular compound deposited on a sampling
safety concerns, if any, associated with its use. It is the
swab for which there is 90 % confidence that a single mea-
responsibility of the user of this standard to establish appro-
surement in a particular ETD will have a true detection
priate safety and health practices and determine the applica-
probability of at least 90 % and a true nondetection probability
bility of regulatory limitations prior to use. Some specific
of at least 90 % when measuring a process blank sample.
hazards statements are given in Section 8 on Hazards.
1.3 This particular test method was chosen on the basis of
reliability, practicability, and comprehensiveness across tested
2. Referenced Documents
ETDs, analytes, and deployment conditions. The calculations
3
2.1 ASTM Standards:
involved in this test method are published elsewhere (4), and
D6091 Practice for 99 %/95 % Interlaboratory Detection
may be performed consistently with an interactive web-based
Estimate (IDE) for Analytical Methods with Negligible
tool available on the National Institute of Standards and
Calibration Error
Technology (NIST) site: http://pubapps.nist.gov/loda.
E177 Practice for Use of the Terms Precision and Bias in
1.4 Intended Users—ETD developers, ETD vendors, ETD
ASTM Test Methods
buyers, ETD testers, ETD users (first responders, security
E200 Practice for Preparation, Standardization, and Storage
screeners, and the military), and agencies responsible for
of Standard and Reagent Solutions for ChemicalAnalysis
public safety and enabling effective deterrents to terrorism.
E288 Specification for Laboratory Glass Volumetric Flasks
1.5 While this test method may be applied to any detection
E456 Terminology Relating to Quality and Statistics
technology that produces numerical output, the procedures E542 Practice for Calibration of Laboratory Volumetric
have been designed for ion mobility spectrometry (IMS) based
Apparatus
ETD systems and tested with low vapor pressure explosive E691 Practice for Conducting an Interlaboratory Study to
compounds. Compounds are deposited as liquid solutions on
Determine the Precision of a Test Method
swabs and dried before use.As some swabs are absorbent, this E969 Specification for Glass Volumetric (Transfer) Pipets
E1154 Specification for Piston or Plunger Operated Volu-
metric Apparatus
1
This test method is under the jurisdiction of ASTM Committee E54 on
Homeland Security Applications and is the direct responsibility of Subcommittee
E54.01 on CBRNE Sensors and Detectors.
3
Current edition approved Feb. 1, 2014. Published February 2014. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
E2677-14. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
...

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ASTM E2520-21(Practice)
Standard Practice for Measuring and Scoring Performance of Trace Explosive Chemical Detectors

SIGNIFICANCE AND USE
5.1 This practice may be used to accomplish several ends: to establish a worldwide frame of reference for terminology, metrics, and procedures for reliably determining trace detection performance of ETDs; as a demonstration by the vendor that the equipment is operating properly to a specified performance score; for a periodic verification by the user of detector performance after purchase; and as a generally-acceptable template adaptable by international agencies to specify performance requirements, analytes and dosing levels, background challenges, and operations.  
5.2 It is expected that current ETD systems will exhibit wide ranges of performance across the diverse explosive types and compounds considered. As in previous versions, this practice establishes the minimum performance that is required for a detector to be considered effective in the detection of trace explosives. An explosives detector is considered to have “minimum acceptable performance” when it has attained a test score of at least 80.
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1.1 This practice may be used for measuring, scoring, and improving the overall performance of detectors that alarm on traces of explosives on swabs. These explosive trace detectors (ETDs) may be based on, but are not limited to, chemical detection technologies such as ion mobility spectrometry (IMS) and mass spectrometry (MS).  
1.2 This practice considers instrumental (post-sampling) trace detection performance, involving specific chemical analytes across eight types of explosive formulations in the presence of a standard background challenge material. This practice adapts Test Method E2677 for the 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 swab area, and estimated maintenance requirements during a typical eight hour shift.  
1.4 This practice does not require, but places extra value on, the specific identification of targeted compounds and explosive formulations.  
1.5 The functionality of multi-mode instruments (those that may be switched between detection of trace explosives, drugs of interest, chemical warfare agents, and other target compounds) may also be tested. A multi-mode instrument under test shall be set to the mode that optimizes operational conditions for the detection of trace explosives. This practice requires the use of a single set of ETD operational settings for calculating a system test score based on the factors described in 1.2, 1.3, and 1.4. A minimum acceptable score is derived from criteria established in Practice E2520 – 07, and an example of such a test is presented in Appendix X1 (Example 2).  
1.6 Intended Users—ETD developers and manufacturers, testing laboratories, and international agencies responsible for enabling effective deterrents to terrorism.  
1.7 Actual explosives as test samples would be preferable, but standard explosive formulations are not widely available, nor are methods for depositing these quantitatively and realistically on swabs. This practice considers sixteen compounds that are available from commercial suppliers. This does not imply that only these sixteen are important to trace detection. Most ETDs are able to detect many other compounds, but these are either chemically similar (hence redundant) to the ones considered, or are unavailable from commercial suppliers for reasons of stability and safety. Under typical laboratory practices, the sixteen compounds considered are safe to handle in the quantities used.  
1.8 This practice is not intended to replace any current standard procedure employed by agencies to test performance of ETDs for specific applications. Those procedures may be more rigorous, use different compounds or actual explosive formulations, employ different or more realistic background...

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Standard Test Method for Estimating Limits of Detection in Trace Detectors for Explosives and Drugs of Interest

SIGNIFICANCE AND USE
5.1 Commercial trace detectors are used by first responders, security screeners, the military, and law enforcement to detect and identify explosive threats and drugs of interest quickly. These trace detectors typically operate by detecting chemical agents in residues and particles sampled from surfaces and can have detection limits for some compounds extending below 1 ng. A trace detector is set to alarm when its response to any target analyte exceeds a programmed threshold level for that analyte. Factory settings of such levels typically balance sensitivity and selectivity assuming standard operating and deployment conditions.  
5.2 The LOD for a substance is commonly accepted as the smallest amount of that substance that can be reliably detected in a given type of medium by a specific measurement process (2). The analytical signal from this amount shall be high enough above ambient background variation to give statistical confidence that the signal is real. Methods for determining nominal LOD values are well known but pitfalls exist in specific applications. Vendors of trace detectors often report detection limits for only a single compound without defining the meaning of terms or reference to the method of determination.
Note 2: There are several different “detection limits” that can be determined for analytical procedures. These include the minimum detectable value, the instrument detection limit, the method detection limit, the limit of recognition, the limit of quantitation, and the minimum consistently detectable amount. Even when the same terminology is used, there can be differences in the LOD according to nuances in the definition used, the assumed response model, and the type of noise contributing to the measurement.  
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1.1 In harmony with the Joint Committee for Guides in Metrology (JCGM) and detection concepts of the International Union of Pure and Applied Chemistry (IUPAC) (1, 2)2, this test method uses a series of replicated measurements of an analyte at dosage levels giving instrumental responses that bracket the critical value, a truncated normal distribution model, and confidence bounds to establish a standard for estimating practical and statistically robust limits of detection.
Note 1: Other standards are available that evaluate the general performance of detection technologies for various analytes in complex matrices (for example, Practice E2520).  
1.2 Here, the limit of detection (LOD90) for a compound is defined to be the lowest mass of that compound deposited on a sampling swab for which there is 90 % confidence that a single measurement in a particular trace detector will have a true detection probability of at least 90 % and a true nondetection probability of at least 90 % when measuring a process blank sample.  
1.3 This particular test method was chosen on the basis of reliability, practicability, and comprehensiveness across tested trace detectors, analytes, and deployment conditions. The calculations involved in this test method are published elsewhere (3), and are performed through an interactive web-based calculator available on the National Institute of Standards and Technology (NIST) site: https://www-s.nist.gov/loda.  
1.4 Intended Users—Trace detector developers and manufacturers, vendors, testing laboratories, and agencies responsible for public safety and enabling effective deterrents to terrorism.  
1.5 While this test method may be applied to any detection technology that produces numerical output, the method is especially applicable to measurement systems influenced by heterogeneous error sources that lead to non-linear and heteroskedastic dose/response relationships and truncated or censored respons...

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Standard Guide for Deployment of Blast Resistant Trash Receptacles in Crowded Places

SIGNIFICANCE AND USE
5.1 This standard is intended to provide guidance on the deployment of blast resistant trash receptacles that focuses on the mitigation of human injury. It is not in general intended to provide guidance on the protection of structures in the vicinity of where the blast resistant trash receptacles are deployed.  
5.2 The importance of a strategy and procedures for the deployment of blast resistant trash receptacles in crowded places cannot be overly emphasized. Trash receptacles in crowded places have been, and continue to be, an attractive repository for explosives. The selection of deployment locations impacts both the mitigation of the effects of an explosion occurring within one as well as the convenience of using the receptacles.  
5.3 Two major effects resulting from an explosion in a trash receptacle are the production of primary and secondary fragments as well as overpressure from the detonation. The recommendations in this guide are intended to mitigate the damaging effects of fragmentation and overpressure in crowded places.  
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5.5 The deployment of blast resistant trash receptacles provides a means for decreasing injury and lethality during an explosive event no matter their location when compared to the protection afforded by ordinary trash receptacles or clear plastic bags. Fragments resulting from explosions create the greatest danger to people as fragments may travel several hundred meters and still have velocities that could be lethal or injurious. Blast resistant trash receptacles that meet the requirements of Specification E2740 when subjected to internal explosions equ...
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1.1 This guide identifies the key factors that should be considered prior to the deployment of blast resistant trash receptacles (BRTRs) in crowded places.  
1.1.1 Guidance is included for their deployment at interior and exterior locations associated with the crowded places.  
1.2 Facilities and venues where blast resistant trash receptacles may be deployed include, but are not limited to:  
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1.2.2 Banks and other financial institutions,  
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1.2.4 Convention centers,  
1.2.5 Entertainment and event centers,  
1.2.6 Hotels,  
1.2.7 Health care locations,  
1.2.8 Museums,  
1.2.9 Places of worship,  
1.2.10 Public government locations including fire and police stations,  
1.2.11 Railway stations, bus stations, and related transit areas,  
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1.2.14 Schools, universities, and related areas used for education,  
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1.2.16 Theaters.  
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Note 1: Much of the literature data for layer ignition is actually from a basket in a heated furnace (4), known as the modified Godbert-Greenwald furnace test. Other data are from nonstandardized hot plates (5-9).  
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1.1 This test method covers a laboratory procedure to determine the hot-surface ignition temperature of dust layers, that is, measuring the minimum temperature at which a dust layer will self-heat. The test consists of a dust layer heated on a hot plate.2,3  
1.2 Data obtained from this test method provide a relative measure of the hot-surface ignition temperature of a dust layer.  
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5.1 This test method provides a procedure for performing laboratory tests to evaluate relative deflagration parameters of dusts.  
5.2 The MEC as measured by this test method provides a relative measure of the concentration of a dust cloud necessary for an explosion.  
5.3 Since the MEC as measured by this test method may vary with the uniformity of the dust dispersion, energy of the ignitor, and propagation criteria, the MEC should be considered a relative rather than absolute measurement.  
5.4 If too weak an ignition source is used, the measured MEC would be higher than the “true” value. This is an ignitability limit rather than a flammability limit, and the test could be described as “underdriven.” Ideally, the ignition energy is increased until the measured MEC is independent of ignition energy. However, at some point the ignition energy may become too strong for the size of the test chamber, and the system becomes “overdriven.” When the ignitor flame becomes too large relative to the chamber volume, a test could appear to result in an explosion, while it is actually just dust burning in the ignitor flame with no real propagation beyond the ignitor.  
5.5 The recommended ignition source for measuring the MEC of dusts in 20-L chambers is a 2500 or 5000 J pyrotechnic ignitor.4 Measuring the MEC at both ignition energies will provide information on the possible overdriving of the system.5 To evaluate the effect of possible overdriving in a 20-L chamber, comparison tests may also be made in a larger chamber, such as a 1 m3-chamber.  
5.6 If a dust ignites with a 5000 J ignitor but not with a 2500 J ignitor in a 20-L chamber, this may be an overdriven system.5 In this case, it is recommended that the dust be tested with a 10 000 J ignitor in a larger chamber, such as a 1 m3-chamber, to determine if it is actually explosible.  
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1.1 This test method covers the determination of the minimum concentration of a dust-air mixture that will propagate a deflagration in a near-spherical closed vessel of 20 L or greater volume.
Note 1: The minimum explosible concentration (MEC) is also referred to as the lower explosibility limit (LEL) or lean flammability limit (LFL).  
1.2 Data obtained from this test method provide a relative measure of the deflagration characteristics of dust clouds.  
1.3 This test method should be used to measure and describe the properties of materials in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment that takes into account all of the factors that are pertinent to an assessment of the fire hazard of a particular end use.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  Specific precautionary statements are given in Section 8.  
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4.1 This test standard describes how to evaluate the relative sensitivity of materials and components to dynamic pressure impacts by various gaseous fluid media (can include gas mixtures).  
4.2 Changes or variations in test specimen configurations, thickness, preparation, and cleanliness can cause a significant change in their impact ignition sensitivity/reaction. For material tests, the test specimen configuration shall be specified on the test report.  
4.3 Changes or variation in the test system configuration from that specified herein may cause a significant change in the severity produced by a dynamic pressure surge of the gaseous media.  
4.4 A reaction is indicated by an abrupt increase in test specimen temperature, by obvious changes in odor, color, or material appearance, or a combination thereof, as observed during post-test examinations. Odor alone is not considered positive evidence that a reaction has occurred. When an increase in test specimen temperature is observed, a test specimen reaction must be confirmed by visual inspection. To aid with visual inspection, magnification less than 10× can be used.  
4.5 When testing components, the test article must be disassembled and the nonmetallic materials examined for evidence of ignition after completion of the specified pressure surge cycles.  
4.6 Ignition or precursors to ignition for any test sample shall be considered a failure and are indicated by burning, material loss, scorching, or melting of a test material detected through direct visual means. Ignition is often indicated by consumption of the non-metallic material under test, whether as an individual material or within a component. Partial ignition can also occur, as shown in Fig. 3a, b, and c, and shall also be considered an ignition (failure) for the purpose of this test standard.
FIG. 3 a Untested PCTFE (10X Magnification) (Polychlorotrifluoroethylene) Sample.  
FIG. 3 b Untested Nylon (PA, polyamide) Valve Seat (10X magnification) (c...
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1.1 This test method describes a method to determine the relative sensitivity of nonmetallic materials (including plastics, elastomers, coatings, etc.) and components (including valves, regulators flexible hoses, etc.) to dynamic pressure impacts by gases such as oxygen, air, or blends of gases containing oxygen.  
1.2 This test method describes the test apparatus and test procedures employed in the evaluation of materials and components for use in gases under dynamic pressure operating conditions up to gauge pressures of 69 MPa and at elevated temperatures.  
1.3 This test method is primarily a test method for ranking of materials and qualifying components for use in gaseous oxygen. The material test method is not necessarily valid for determination of the sensitivity of the materials in an “as-used” configuration since the material sensitivity can be altered because of changes in material configuration, usage, and service conditions/interactions. However, the component testing method outlined herein can be valid for determination of the sensitivity of components under service conditions. The current provisions of this method were based on the testing of components having an inlet diameter (ID bore) less than or equal to 14 mm (see Note 1).  
1.4 A 5 mm Gaseous Fluid Impact Sensitivity (GFIS) test system and a 14 mm GFIS test system are described in this standard. The 5 mm GFIS system is utilized for materials and components that are directly attached to a high-pressure source and have minimal volume between the material/component and the pressure source. The 14 mm GFIS system is utilized for materials and components that are attached to a high pressure source through a manifold or other higher volume or larger sized connection. Other sizes than these may be utilized but no attempt has been made to characterize the thermal profiles of other volumes and geometries (see Note 1).
Note 1: The energy delivered by this t...

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ASTM
ASTM E2520-21(Practice)
Standard Practice for Measuring and Scoring Performance of Trace Explosive Chemical Detectors

SIGNIFICANCE AND USE
5.1 This practice may be used to accomplish several ends: to establish a worldwide frame of reference for terminology, metrics, and procedures for reliably determining trace detection performance of ETDs; as a demonstration by the vendor that the equipment is operating properly to a specified performance score; for a periodic verification by the user of detector performance after purchase; and as a generally-acceptable template adaptable by international agencies to specify performance requirements, analytes and dosing levels, background challenges, and operations.  
5.2 It is expected that current ETD systems will exhibit wide ranges of performance across the diverse explosive types and compounds considered. As in previous versions, this practice establishes the minimum performance that is required for a detector to be considered effective in the detection of trace explosives. An explosives detector is considered to have “minimum acceptable performance” when it has attained a test score of at least 80.
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1.1 This practice may be used for measuring, scoring, and improving the overall performance of detectors that alarm on traces of explosives on swabs. These explosive trace detectors (ETDs) may be based on, but are not limited to, chemical detection technologies such as ion mobility spectrometry (IMS) and mass spectrometry (MS).  
1.2 This practice considers instrumental (post-sampling) trace detection performance, involving specific chemical analytes across eight types of explosive formulations in the presence of a standard background challenge material. This practice adapts Test Method E2677 for the 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 swab area, and estimated maintenance requirements during a typical eight hour shift.  
1.4 This practice does not require, but places extra value on, the specific identification of targeted compounds and explosive formulations.  
1.5 The functionality of multi-mode instruments (those that may be switched between detection of trace explosives, drugs of interest, chemical warfare agents, and other target compounds) may also be tested. A multi-mode instrument under test shall be set to the mode that optimizes operational conditions for the detection of trace explosives. This practice requires the use of a single set of ETD operational settings for calculating a system test score based on the factors described in 1.2, 1.3, and 1.4. A minimum acceptable score is derived from criteria established in Practice E2520 – 07, and an example of such a test is presented in Appendix X1 (Example 2).  
1.6 Intended Users—ETD developers and manufacturers, testing laboratories, and international agencies responsible for enabling effective deterrents to terrorism.  
1.7 Actual explosives as test samples would be preferable, but standard explosive formulations are not widely available, nor are methods for depositing these quantitatively and realistically on swabs. This practice considers sixteen compounds that are available from commercial suppliers. This does not imply that only these sixteen are important to trace detection. Most ETDs are able to detect many other compounds, but these are either chemically similar (hence redundant) to the ones considered, or are unavailable from commercial suppliers for reasons of stability and safety. Under typical laboratory practices, the sixteen compounds considered are safe to handle in the quantities used.  
1.8 This practice is not intended to replace any current standard procedure employed by agencies to test performance of ETDs for specific applications. Those procedures may be more rigorous, use different compounds or actual explosive formulations, employ different or more realistic background...

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ASTM
ASTM E2677-20(Test Method)
Standard Test Method for Estimating Limits of Detection in Trace Detectors for Explosives and Drugs of Interest

SIGNIFICANCE AND USE
5.1 Commercial trace detectors are used by first responders, security screeners, the military, and law enforcement to detect and identify explosive threats and drugs of interest quickly. These trace detectors typically operate by detecting chemical agents in residues and particles sampled from surfaces and can have detection limits for some compounds extending below 1 ng. A trace detector is set to alarm when its response to any target analyte exceeds a programmed threshold level for that analyte. Factory settings of such levels typically balance sensitivity and selectivity assuming standard operating and deployment conditions.  
5.2 The LOD for a substance is commonly accepted as the smallest amount of that substance that can be reliably detected in a given type of medium by a specific measurement process (2). The analytical signal from this amount shall be high enough above ambient background variation to give statistical confidence that the signal is real. Methods for determining nominal LOD values are well known but pitfalls exist in specific applications. Vendors of trace detectors often report detection limits for only a single compound without defining the meaning of terms or reference to the method of determination.
Note 2: There are several different “detection limits” that can be determined for analytical procedures. These include the minimum detectable value, the instrument detection limit, the method detection limit, the limit of recognition, the limit of quantitation, and the minimum consistently detectable amount. Even when the same terminology is used, there can be differences in the LOD according to nuances in the definition used, the assumed response model, and the type of noise contributing to the measurement.  
5.3 When deployed, the individual performance of a trace detector (for example, realistic LODs) is influenced by: (1) manufacturing differences, history, and maintenance; (2) operating configurations (for example, thermal desorption tem...
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1.1 In harmony with the Joint Committee for Guides in Metrology (JCGM) and detection concepts of the International Union of Pure and Applied Chemistry (IUPAC) (1, 2)2, this test method uses a series of replicated measurements of an analyte at dosage levels giving instrumental responses that bracket the critical value, a truncated normal distribution model, and confidence bounds to establish a standard for estimating practical and statistically robust limits of detection.
Note 1: Other standards are available that evaluate the general performance of detection technologies for various analytes in complex matrices (for example, Practice E2520).  
1.2 Here, the limit of detection (LOD90) for a compound is defined to be the lowest mass of that compound deposited on a sampling swab for which there is 90 % confidence that a single measurement in a particular trace detector will have a true detection probability of at least 90 % and a true nondetection probability of at least 90 % when measuring a process blank sample.  
1.3 This particular test method was chosen on the basis of reliability, practicability, and comprehensiveness across tested trace detectors, analytes, and deployment conditions. The calculations involved in this test method are published elsewhere (3), and are performed through an interactive web-based calculator available on the National Institute of Standards and Technology (NIST) site: https://www-s.nist.gov/loda.  
1.4 Intended Users—Trace detector developers and manufacturers, vendors, testing laboratories, and agencies responsible for public safety and enabling effective deterrents to terrorism.  
1.5 While this test method may be applied to any detection technology that produces numerical output, the method is especially applicable to measurement systems influenced by heterogeneous error sources that lead to non-linear and heteroskedastic dose/response relationships and truncated or censored respons...

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