ASTM E2677-14
测定爆炸物追踪检测器检测限制的标准试验方法

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

被代替

标准号

ASTM E2677-14

发布

2014年

发布单位

美国材料与试验协会

替代标准

ASTM E2677-20

当前最新

ASTM E2677-20

 

 

引用标准

ASTM D6091 ASTM E1154 ASTM E1323 ASTM E177 ASTM E200 ASTM E2520 ASTM E2655 ASTM E288 ASTM E456 ASTM E542 ASTM E691 ASTM E969

适用范围

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 example, ambient humidity and temperature and chemical background). As a result, realistic LOD values for an ETD may be poorly estimated by the factory specifications. These fundamental measures of ETD performance are critically important for assessing the ability of an ETD to detect trace levels of particular compounds in a particular setting, so a reliable and accessible method is needed to determine realistic LOD values, especially in the field.

5.4 Technical Challenges and Pitfalls to the Determination of LOD Values in ETDs and the Setting of Optimal Alarm Thresholds:

5.4.1 Scope—There are over 230 explosive materials currently listed by the Bureau of Alcohol, Tobacco, Firearms, and Explosives.⁴ There are many technologies used for detection, and ETD manufacturers design their systems and balance operating conditions to provide detection capabilities across as many analytes as possible. However, a very limited subset of analytes is normally used to test and verify ETD performance. Therefore, default ETD operating conditions and alarm thresholds may not be optimally set to detect reliably certain compounds deemed important in particular scenarios.

3Q认证及审计追踪色谱工作站简析

4.检测器 液相色谱仪检测器有紫外一可见光检测器、 荧光检测器、 示差折光率检测器、 蒸发光散射检测器和电化学检测器等。 不同的检测器有不同的测定方法。...