Validation of an Evacuated Canister Method for Measuring Part-Per-Billion Levels of Chemical Warfare Agent Simulants

Figures & data

Table 1. Stability data sampling schedule

Total Number of Canisters Analyzed Per Day	Number of Days after Filling When Analyzed
13	0
8	7
5	14
7	21
6	30

Table 2. LOD and LOQ values

Compound	LOD (ppb)	LOQ (ppb)
Acetone	0.47	1.56
Methylene chloride	0.25	0.83
Methyl ethyl ketone	0.68	2.27
Hexane	0.30	0.98
Chloroform	0.30	0.99
CCl4	0.39	1.30
Cyclohexane	0.26	0.88

Table 3. Aliquots and concentrations for instrument operating range concentration calibration

Aliquot (mL)	Calibration Concentration (ppb)
500 ^a	0
50	5
100	10
200	20
300	30
500	50
Notes: ^aAliquot was ultrahigh-purity humidified nitrogen.

Figure 1. Representative graph of aliquot size vs. peak area for ppb concentration method to determine the upper limit of the method's operating range.

Figure 2. Aliquot volume of 300 mL, equaling a 60-ppb sample of TO-15, shows poor separation of compounds and tailing peaks, indicating the volume amount of sample is too high.

Figure 3. Aliquot volume of 250 mL, equaling a 50-ppb sample of TO-15, showing better separation of compounds.

Table 4. Results of precision, bias, and accuracy analysis for the ppb-concentration level method

Compound	Bias	Precision	Accuracy	90% Confidence Interval for Accuracy
Acetone	−2.7	3.2	7.8	6.3–9.7
Methylene chloride	−7.0	2.4	10.6	9.4–12.1
Methyl ethyl ketone	−5.3	2.9	9.7	8.2–11.5
Hexane	−7.5	2.7	11.5	10.2–13.2
Chloroform	−8.5	2.6	12.2	10.9–13.8
CCl4	−7.5	2.9	11.8	10.4–13.7
Cyclohexane	−5.1	2.6	9.1	7.8–10.8
Notes: All values displayed as percentage.