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

Table 6

Evaluation of the chromatographic peak area of the VX agent and di-n-hexylamine at m/z 114 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
	VX	Dihexyl-amine	VX	Dihexyl-amine	VX	Dihexyl-amine
Retention time (min)	22.1	17.0	18.6	14.4	23.8	17.7
Linearity range (mg/L)	7.5–20	7.5–20	7.5–20	7.5–20	15–50	15–50
R	0.9934	0.9981	0.9987	0.9938	0.9999	0.9999
QC	4.38	4.81	4.68	3.89	0.43	0.23
Gradient (A × 10^−6 × L/mg)	0.38	0.67	0.24	0.45	0.020	0.036
Intercept (A × 10^−6)	−0.21	−0.49	−0.031	0.033	0.0013	−0.0023
Response factor FR	0.57		0.54		0.55
Average value of FR			0.55