Internal Standards for Quantitative Analysis of Chemical Warfare Agents by the GC/MS Method: Nerve Agents

Table 7

Evaluation of the chromatographic peak area of edemo and tri-n-butylphosphate at m/z 99 as a linear function of their concentration (critical values of the correlation coefficient R_CRIT 0.99 and QC coefficient QC_CRIT 5.00).

GC/MS compound	7890A/5975C		Intuvo 9000/5977B		EM 640
	Edemo	Tributyl-phosphate	Edemo	Tributyl-phosphate	Edemo	Tributyl-phosphate
Retention time (min)	20.5	21.2	16.4	17.1	18.9	19.6
Linearity range (mg/L)	5–30	5–30	2.5–15	2.5–12.5	10–50	10–50
R	0.9964	0.9996	0.9980	0.9967	0.9978	0.9981
QC	4.00	2.14	4.62	4.53	3.29	3.17
Gradient (A × 10^−6 × L/mg)	1.1	4.2	0.16	0.61	0.014	0.054
Intercept (A × 10^−6)	−0.18	−2.1	−0.012	−0.11	0.0017	0.0045
Response factor FR	0.25		0.27		0.26
Average value of FR			0.26