Standard Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Static Headspace Concentration onto an Adsorbent Tube

Importancia y uso:

5.1 This practice is useful for preparing extracts from fire debris for subsequent qualitative analysis by gas chromatography-mass spectrometry, see Test Method E1618.

5.2 This practice is capable of removing a portion of the headspace vapors, containing quantities smaller than 0.1 µL/L of ignitable liquid residues, from a sample container and concentrating the ignitable liquid residues onto an adsorbent medium (1).

5.2.1 Recovery from fire debris samples will vary, depending on factors including debris temperature, adsorbent temperature, container size, adsorptive material, headspace volume, sampling volume or sampling time and flow rate, and adsorptive competition from the sample matrix (2).

5.3 The principal concepts of static headspace concentration are similar to those of static headspace (Practice E1388) and dynamic headspace concentration (Practice E1413). The static headspace concentration technique can be more sensitive than the static headspace technique and less sensitive than the dynamic. The static techniques do however leave the sample in a condition suitable for resampling, as only a portion, typically less than 10 %, of the headspace is withdrawn from a sample container (3).

5.3.1 Re-sampling and analysis is possible with static headspace concentration onto an adsorbent tube, because only a portion of the headspace from the container is removed (3). Taking multiple headspace samples will continuously reduce the concentration of ignitable liquid vapors present, which can result in a change in relative composition of components and eventually non-recovery when the questioned headspace originally contained very low quantities of ignitable liquid residues (less than 0.1 µL/L).

5.4 Common solid adsorbent/desorption procedure combinations in use are activated carbon/solvent elution and Tenax5 TA/thermal desorption.

5.5 Solid adsorbent/desorption procedures not specifically described in this standard can be used as long as the practice has been validated as outlined in Section 11.

Subcomité:

E30.13

Referida por:

E3197-23, E2997-25, E1386-23, E2881-25, E1732-25E01, E1413-19, E1388-24, E2451-21, E3245-20E01

Volúmen:

14.02

Número ICS:

13.220.99 (Other standards related to protection against fire)

Palabras clave:

activated carbon; adsorbent tube; elution; fire debris samples; forensic science; gas chromatography-mass spectrometry; ignitable liquid residues; static headspace concentration; Tenax TA; thermal desorption;